Additionally, each facet definition element can be uniquely
addressed via a URI constructed as follows:
Additionally, each facet usage in a built-in datatype definition
can be uniquely addressed via a URI constructed as follows:
For example, to address the usage of the maxInclusive facet in
the definition of int, the URI is:
3.1 Namespace considerations
The ·built-in· datatypes defined by this specification
are designed to be used with the XML Schema definition language as well as other
XML specifications.
To facilitate usage within the XML Schema definition language, the ·built-in·
datatypes in this specification have the namespace name:
- http://www.w3.org/2001/XMLSchema
To facilitate usage in specifications other than the XML Schema definition language,
such as those that do not want to know anything about aspects of the
XML Schema definition language other than the datatypes, each ·built-in·
datatype is also defined in the namespace whose URI is:
- http://www.w3.org/2001/XMLSchema-datatypes
This applies to both
·built-in· ·primitive· and
·built-in· ·derived· datatypes.
Each ·user-derived· datatype is also associated with a
unique namespace. However, ·user-derived· datatypes
do not come from the namespace defined by this specification; rather,
they come from the namespace of the schema in which they are defined
(see XML Representation of
Schemas in [XML Schema Part 1: Structures]).
3.2 Primitive datatypes
The ·primitive· datatypes defined by this specification
are described below. For each datatype, the
·value space· and ·lexical space·
are defined, ·constraining facet·s which apply
to the datatype are listed and any datatypes ·derived·
from this datatype are specified.
·primitive· datatypes can only be added by revisions
to this specification.
3.2.1 string
[Definition:] The string datatype
represents character strings in XML. The ·value space·
of string is the set of finite-length sequences of
characters (as defined in
[XML]) that ·match· the
Char production from [XML].
A character is an atomic unit of
communication; it is not further specified except to note that every
character has a corresponding
Universal Character Set code point, which is an integer.
Note:
As noted in
ordered, the fact that this specification does
not specify an
↓·order-relation·↓↑order relation↑ for
·string·
does not preclude other applications from treating
strings as being ordered.
3.2.2 boolean
[Definition:] boolean has the
·value space· required to support the mathematical
concept of binary-valued logic: {true, false}.
3.2.2.1 Lexical representation
An instance of a datatype that is defined as ·boolean·
can have the following legal literals {true, false, 1, 0}.
3.2.2.2 Canonical representation
The canonical representation for boolean is the set of
literals {true, false}.
3.2.3 decimal
Issue (RQ-150i):RQ-150 (minimum number of digits for decimal)The minimum number of digits implementations are required to support
will be lowered to 16 digits; a health warning will be added to note
that implementations of derived datatypes may support more digits of
precision than the base decimal type does, but that they are not required
to do so.
[Definition:] decimal
represents a subset of the real numbers, which can be represented by decimal numerals.
The ·value space· of decimal
is the set of numbers that can be obtained by
↓multiplying↓↑dividing↑
an integer by a non-↓positive↓↑negative↑
power of ten, i.e., expressible as
↓i × 10^-n↓↑i / 10n↑
where i and n are integers
and
↓n >= 0↓↑n ≥ 0↑.
Precision is not reflected in this value space;
the number 2.0 is not distinct from the number 2.00.
↑(The datatype pDecimal may be used
for values in which precision is significant.)↑
The ↓·order-relation·↓↑order relation↑ on decimal
is the order relation on real numbers, restricted
to this subset.
Note: All
·minimally conforming· processors
·must· support decimal numbers with a minimum of
↓18↓↑16↑ decimal digits
(i.e.,
↓with a
·totalDigits·↓ of 18
↑they must support all values which would be
allowed by a simple type definition which set
totalDigits to 16↑). However,
·minimally conforming· processors
·may· set
an application-defined limit on the maximum number of decimal digits
they are prepared to support, in which case that application-defined
maximum number
·must· be clearly documented.
3.2.3.1 Lexical representation
decimal has a lexical representation
consisting of a finite-length sequence of decimal digits (#x30-#x39) separated
by a period as a decimal indicator.
An optional leading sign is allowed.
If the sign is omitted, "+" is assumed. Leading and trailing zeroes are optional.
If the fractional part is zero, the period and following zero(es) can
be omitted.
For example: -1.23, 12678967.543233, +100000.00, 210.
↑
The lexical space of decimal is the set of
lexical representations which match the grammar given above, or
(equivalently) the regular expression
'-?(([0-9]+(.[0-9]*)?)|(.[0-9]+))'.
↑
↑
The mapping from lexical representations to values is the usual
one for decimal numerals; it is given formally in:
↑
3.2.3.2 Canonical representation
The canonical representation for decimal is defined by
prohibiting certain options from the
Lexical representation (§3.2.3.1). Specifically, the preceding
optional "+" sign is prohibited. The decimal point is required. Leading and
trailing zeroes are prohibited subject to the following: there must be at least
one digit to the right and to the left of the decimal point which may be a zero.
↑
The mapping from values to canonical representations
is given formally in:
↑
3.2.3.4 ↓Derived datatypes↓↑Datatypes based on decimal↑
The following ·built-in·
datatypes are ·derived· from
decimal:
↑
3.2.4 pDecimal
[Definition:] The pDecimal
datatype represents the
numeric value and (arithmetic) precision of decimal numbers which retain
precision; it also
includes special values for positive and negative infinity and
"not a number", and it differentiates
between "positive zero" and "negative
zero". The special values are
introduced to make the datatype correspond closely to
the
floating-point decimal datatypes described by the forthcoming
revision of IEEE/ANSI 754.
Precision is sometimes given in absolute, sometimes in relative
terms. [Definition:] The arithmetic precision of a value is
expressed in absolute quantitative terms,
by indicating
how many digits to the right of the decimal point are significant.
"5" has an arithmetic precision of 0, and
"5.01" an arithmetic precision of 2.
3.2.4.1 Value Space
a decimal number, positiveInfinity,
negativeInfinity or notANumber
Note: As explained below, the lexical
representation of the
pDecimal value object whose
·numericalValue·
is
notANumber is '
NaN'. Accordingly, in English text we
use 'NaN' to refer to that value. Similarly we use 'INF'
and '–INF' to refer to the two value objects whose
·numericalValue·
is
positiveInfinity and
negativeInfinity. These three value objects
are also informally called "not-a-number", "positive infinity",
and "negative infinity".
The latter two together are called
"the infinities".
Equality and order for pDecimal are defined as follows:
- Two numerical pDecimal values
are ordered (or equal) as their
·numericalValue· values are ordered (or equal).
(This means
that
two zeros with
different ·sign·s
are equal;
negative zeros are not ordered less than positive zeros.)
- INF is equal only to itself, and is greater than
–INF and all numerical pDecimal values.
- –INF is equal only to itself, and is less than
INF and all numerical pDecimal values.
- NaN is incomparable with all values, including
itself.
3.2.4.2 Lexical Mapping
pDecimal's lexical space is the set of all
decimal numerals with or without a decimal
point, numerals in scientific (exponential) notation, and
the character strings 'INF',
'+INF', '-INF',
and 'NaN'.
The lexicalMappings
facet can remove any one or two of the three subsets of
numerals, with corresponding reductions in
the value space. Using this facet
rather than pattern will change the canonical
mapping to insure that the resulting datatype will still have canonical
representations of all its values.
The lexical mapping and canonical mapping
for pDecimal are the following functions:
↑
3.2.5 float
[Definition:] float
is patterned after the IEEE single-precision 32-bit floating point type
[IEEE 754-1985]. The basic ·value space· of
float consists of the values
m × 2^e, where m
is an integer whose absolute value is less than
2^24, and e is an integer
between -149 and 104, inclusive. In addition to the basic
·value space· described above, the
·value space· of float also contains the
following
three
special values:
positive and negative infinity and not-a-number
(NaN).
The ↓·order-relation·↓↑order relation↑ on float
is: x < y iff y - x is positive
for x and y in the value space.
Positive infinity is greater than all other non-NaN values.
NaN equals itself but is incomparable with (neither greater than nor less than)
any other value in the ·value space·.
Note:
"Equality" in this Recommendation is defined to be "identity" (i.e., values that
are identical in the
·value space· are equal and vice versa).
Identity must be used for the few operations that are defined in this Recommendation.
Applications using any of the datatypes defined in this Recommendation may use different
definitions of equality for computational purposes;
[IEEE 754-1985]-based computation systems
are examples. Nothing in this Recommendation should be construed as requiring that
such applications use identity as their equality relationship when computing.
Any value incomparable with the value used for the four bounding facets
(
·minInclusive·,
·maxInclusive·,
·minExclusive·, and
·maxExclusive·) will be
excluded from the resulting restricted
·value space·. In particular,
when "NaN" is used as a facet value for a bounding facet, since no other
float values are
·comparable· with it,
the result is a
·value space·
either having NaN as its only member (the inclusive cases) or that is empty
(the exclusive cases). If any other value is used for a bounding facet,
NaN will be excluded from the resulting restricted
·value space·;
to add NaN back in requires union with the NaN-only space.
This datatype differs from that of
[IEEE 754-1985] in that there is only one
NaN and only one zero. This makes the equality and ordering of values in the data
space differ from that of
[IEEE 754-1985] only in that for schema purposes NaN = NaN.
A literal in the ·lexical space· representing a
decimal number d maps to the normalized value
in the ·value space· of float that is
closest to d in the sense defined by
[Clinger, WD (1990)]; if d is
exactly halfway between two such values then the even value is chosen.
3.2.5.1 Lexical representation
float values have a lexical representation
consisting of a mantissa followed, optionally, by the character
'E' or 'e',
followed by an exponent. The exponent ·must·
be an integer. The mantissa must be a
decimal number. The representations
for exponent and mantissa must follow the lexical rules for
integer and decimal. If the
'E' or 'e' and
the following exponent are omitted, an exponent value of 0 is assumed.
The special values
positive
and negative infinity and not-a-number have lexical representations
INF, -INF and
NaN, respectively.
Lexical representations for zero may take a positive or negative sign.
For example, -1E4, 1267.43233E12, 12.78e-2, 12
, -0, 0
and INF are all legal literals for float.
3.2.5.2 Canonical representation
↓
The canonical representation for float is defined by
prohibiting certain options from the
Lexical representation (§3.2.5.1). Specifically, the exponent
must be indicated by "E". Leading zeroes and the preceding optional "+" sign
are prohibited in the exponent.
If the exponent is zero, it must be indicated by "E0".
For the mantissa, the preceding optional "+" sign is prohibited
and the decimal point is required.
Leading and trailing zeroes are prohibited subject to the following:
number representations must
be normalized such that there is a single digit
which is non-zero
to the left of the decimal point and at least a single digit to the
right of the decimal point
unless the value being represented is zero. The canonical
representation for zero is 0.0E0.
↓
↑
NaN has the canonical form 'NaN'. Infinity and
negative infinity have the canonical forms 'INF' and
'-INF' respectively. Besides these special
values, the general form of the canonical form for float
is a mantissa, which is a decimal, followed by 'E'
followed by an exponent which is an integer. Leading zeroes and
the preceding optional '+' sign are prohibited in the
exponent. If the exponent is zero it must be indicated by
'E0'. For the mantissa, the preceding optional
'+' sign is prohibited and the decimal point is
required. Leading and trailing zeroes are prohibited subject to
the following: number representations must be normalized such that
there is a single digit which is non-zero to the left of the decimal
point and at least a single digit to the right of the decimal point
unless the value being represented is zero. The canonical form of
positive zero is 0.0E0. The canonical form for negative zero
is -0.0E0. Beyond the one required digit after the decimal point
in the mantissa, there must be as many, but only as many, additional
digits as are needed to uniquely distinguish the value from all other
values for the datatype after rounding.
↑
3.2.6 double
[Definition:] The double
datatype
is patterned after the
IEEE double-precision 64-bit floating point
type [IEEE 754-1985]. The basic ·value space·
of double consists of the values
m × 2^e, where m
is an integer whose absolute value is less than
2^53, and e is an
integer between -1075 and 970, inclusive. In addition to the basic
·value space· described above, the
·value space· of double also contains
the following
three
special values:
positive and negative infinity and not-a-number
(NaN).
The ↓·order-relation·↓↑order relation↑ on double
is: x < y iff y - x is positive
for x and y in the value space.
Positive infinity is greater than all other non-NaN values.
NaN equals itself but is incomparable with (neither greater than nor less than)
any other value in the ·value space·.
Note:
"Equality" in this Recommendation is defined to be "identity" (i.e., values that
are identical in the
·value space· are equal and vice versa).
Identity must be used for the few operations that are defined in this Recommendation.
Applications using any of the datatypes defined in this Recommendation may use different
definitions of equality for computational purposes;
[IEEE 754-1985]-based computation systems
are examples. Nothing in this Recommendation should be construed as requiring that
such applications use identity as their equality relationship when computing.
Any value incomparable with the value used for the four bounding facets
(
·minInclusive·,
·maxInclusive·,
·minExclusive·, and
·maxExclusive·) will be
excluded from the resulting restricted
·value space·. In particular,
when "NaN" is used as a facet value for a bounding facet, since no other
double values are
·comparable· with it,
the result is a
·value space·
either having NaN as its only member (the inclusive cases) or that is empty
(the exclusive cases). If any other value is used for a bounding facet,
NaN will be excluded from the resulting restricted
·value space·;
to add NaN back in requires union with the NaN-only space.
This datatype differs from that of
[IEEE 754-1985] in that there is only one
NaN and only one zero. This makes the equality and ordering of values in the data
space differ from that of
[IEEE 754-1985] only in that for schema purposes NaN = NaN.
A literal in the ·lexical space· representing a
decimal number d maps to the normalized value
in the ·value space· of double that is
closest to d; if d is
exactly halfway between two such values then the even value is chosen.
This is the best approximation of d
([Clinger, WD (1990)], [Gay, DM (1990)]), which is more
accurate than the mapping required by [IEEE 754-1985].
3.2.6.1 Lexical representation
double values have a lexical representation
consisting of a mantissa followed, optionally, by the character "E" or
"e", followed by an exponent. The exponent ·must· be
an integer. The mantissa must be
a decimal number. The representations
for exponent and mantissa must follow the lexical rules for
integer and
decimal. If the 'E' or 'e' and
the following exponent are omitted, an exponent value of 0 is assumed.
The special values
positive
and negative infinity and not-a-number have lexical representations
INF, -INF and
NaN, respectively.
Lexical representations for zero may take a positive or negative sign.
For example, -1E4, 1267.43233E12, 12.78e-2, 12
, -0, 0
and INF
are all legal literals for double.
3.2.6.2 Canonical representation
↓
The canonical representation for double is defined by
prohibiting certain options from the
Lexical representation (§3.2.6.1). Specifically, the exponent
must be indicated by "E". Leading zeroes and the preceding optional "+" sign
are prohibited in the exponent.
If the exponent is zero, it must be indicated by "E0".
For the mantissa, the preceding optional "+" sign is prohibited
and the decimal point is required.
Leading and trailing zeroes are prohibited subject to the following:
number representations must
be normalized such that there is a single digit
which is non-zero
to the left of the decimal point and at least a single digit to the
right of the decimal point
unless the value being represented is zero. The canonical
representation for zero is 0.0E0.
↓
↑
NaN has the canonical form 'NaN'. Infinity and
negative infinity have the canonical forms 'INF' and
'-INF' respectively. Besides these special
values, the general form of the canonical form for double
is a mantissa, which is a decimal, followed by 'E'
followed by an exponent which is an integer. Leading zeroes and
the preceding optional '+' sign are prohibited in the
exponent. If the exponent is zero it must be indicated by
'E0'. For the mantissa, the preceding optional
'+' sign is prohibited and the decimal point is
required. Leading and trailing zeroes are prohibited subject to
the following: number representations must be normalized such that
there is a single digit which is non-zero to the left of the decimal
point and at least a single digit to the right of the decimal point
unless the value being represented is zero. The canonical form of
positive zero is 0.0E0. The canonical form for negative zero
is -0.0E0. Beyond the one required digit after the decimal point
in the mantissa, there must be as many, but only as many, additional
digits as are needed to uniquely distinguish the value from all other
values for the datatype after rounding.
↑
3.2.7 duration
↓
[Definition:]
duration represents a duration of time. The ·value space· of duration is a six-dimensional
space where the coordinates designate the Gregorian year, month, day,
hour, minute, and second components defined in § 5.5.3.2 of
[ISO 8601], respectively. These components are ordered
in their significance by their order of appearance i.e. as year,
month, day, hour, minute, and second.
↓
↓
Note:
All
·minimally conforming· processors
·must· support year values with a minimum of 4 digits (i.e.,
YYYY) and a minimum fractional second precision of
milliseconds or three decimal digits (i.e.
s.sss).
However,
·minimally conforming· processors
·may· set an application-defined limit on the maximum number
of digits they are prepared to support in these two cases, in which
case that application-defined maximum number
·must·
be clearly documented.
↓
↑
[Definition:] duration is a datatype that represents
durations of time. The concept of duration being captured is
drawn from those of [ISO 8601], specifically
durations without fixed endpoints. For example,
"15 days" (whose most common lexical representation
in duration is "'P15D'") is
a duration value; "15 days beginning 12 July
1995" and "15 days ending 12 July 1995" are
not. duration can provide addition and
subtraction operations between duration values and
between duration/dateTime value pairs,
and can be the result of subtracting dateTime
values. However, only addition to and subtraction from dateTime is required for XML Schema processing
and is defined in Adding durations to dateTimes (§H).
↑
↑
3.2.7.1 Value Space
Durations can be modeled in at least two ways: as six-property tuples (similar to
the seven-property model used for other date/time datatypes) or as two-property tuples
(somewhat similar to the alternative one-property timeOnTimeline model especially useful for
dateTime order). For
durations, it is useful to use the latter: duration values are two-property
tuples. (Note, however, that the
six-property model was implicitly used in Schema 1.0. The only effective difference to the user caused
by this change is in the canonical representations.) See
The Seven-property Model (§D.2.1) for more information on the seven-property model.
duration is partially ordered. Equality and order are defined in terms of that of
dateTime, and are determined by adding each duration value pair
in turn to the following four dateTime values:
- 1696-09-01T00:00:00Z
- 1697-02-01T00:00:00Z
- 1903-03-01T00:00:00Z
- 1903-07-01T00:00:00Z
If all four resulting dateTime value pairs are
ordered the same way (less than, equal, or greater than), then the
original pair of duration values is ordered the same way; otherwise the original pair
is incomparable.
Note: These four values are chosen so as to maximize
the possible differences in results that could occur, such as the difference when adding
P1M and P30D: 1697-02-01T00:00:00Z + P1M < 1697-02-01T00:00:00Z + P30D ,
but 1903-03-01T00:00:00Z + P1M > 1903-03-01T00:00:00Z + P30D , so
that P1M <> P30D . If two
duration values are ordered the same way
when added to each of these four
dateTime values, they will retain the same order when added
to
any other
dateTime values, unless one is within a leap-second and either the other
is also or is the beginning moment of the next second—in which case, the two results will
be equal even though the original
dateTime values were not. Therefore, two
duration values are
incomparable if and only if they can
ever result in different orders when added to
any
dateTime value not within a leap-second.
This minor anomaly is the result of having
duration unaware of leap-seconds while the
other date/time primitive datatypes are leap-second aware.
It turns out that under the definition just given, two duration
values are equal if and only if they are identical.
Note: There are many ways to implement
duration,
some of which do not base the implementation on the two-component
model. This specification does not prescribe any particular
implementation, as long as the visible results are isomorphic to those
described herein.
↑
↓
3.2.7.2 Lexical representation
The lexical representation for duration is the
[ISO 8601] extended format PnYn
MnDTnH nMnS, where
nY represents the number of years, nM the
number of months, nD the number of days, 'T' is the
date/time separator, nH the number of hours,
nM the number of minutes and nS the
number of seconds. The number of seconds can include decimal digits
to arbitrary precision.
The values of the
Year, Month, Day, Hour and Minutes components are not restricted but
allow an arbitrary
integer.
Similarly, the value of the Seconds component
allows an arbitrary decimal.
Thus, the lexical representation of
duration does not follow the alternative
format of § 5.5.3.2.1 of [ISO 8601].
An optional preceding minus sign ('-') is
allowed, to indicate a negative duration. If the sign is omitted a
positive duration is indicated. See also ISO 8601 Date and Time Formats (§G).
For example, to indicate a duration of 1 year, 2 months, 3 days, 10
hours, and 30 minutes, one would write: P1Y2M3DT10H30M.
One could also indicate a duration of minus 120 days as:
-P120D.
Reduced precision and truncated representations of this format are allowed
provided they conform to the following:
-
If the number of years, months, days, hours, minutes, or seconds in any
expression equals zero, the number and its corresponding designator ·may·
be omitted. However, at least one number and its designator ·must·
be present.
-
The seconds part ·may· have a decimal fraction.
-
The designator 'T' shall
be absent if all of the time items are absent.
The designator 'P' must always be present.
For example, P1347Y, P1347M and P1Y2MT2H are all allowed;
P0Y1347M and P0Y1347M0D are allowed. P-1347M is not allowed although
-P1347M is allowed. P1Y2MT is not allowed.
↓
↑
3.2.7.3 Lexical Space
The ·lexical representations· of duration are
more or less based on the pattern:
PnYnMnDTnHnMnS
More precisely, the ·lexical space· of duration is the set of character
strings that satisfy durationLexicalRep as defined by the following productions:
Lexical Representation Fragments
Thus, a durationLexicalRep consists of one or more of a duYearFrag,
duMonthFrag, duDayFrag, duHourFrag,
duMinuteFrag, and/or duSecondFrag, in order, with letters
'P' and 'T' (and perhaps a '-') where appropriate.
The durationLexicalRep is equivalent to this regular expression
-?P(((([0-9]+Y([0-9]+M)?)|
( ([0-9]+M) ) )(([0-9]+D(T(([0-9]+H([0-9]+M)?([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+M) ([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+(\.[0-9]+)?S) ) ))?)|
( (T(([0-9]+H([0-9]+M)?([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+M) ([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+(\.[0-9]+)?S) ) )) ) )?)|
( (([0-9]+D(T(([0-9]+H([0-9]+M)?([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+M) ([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+(\.[0-9]+)?S) ) ))?)|
( (T(([0-9]+H([0-9]+M)?([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+M) ([0-9]+(\.[0-9]+)?S)?)|
( ([0-9]+(\.[0-9]+)?S) ) )) ) ) ) )
once you delete the
whitespace. Redundant parentheses are shown as
"ghosts"; some find them helpful in reading the expression.)
↑
↓
3.2.7.4 Order relation on duration
In general, the ·order-relation· on duration
is a partial order since there is no determinate relationship between certain
durations such as one month (P1M) and 30 days (P30D).
The ·order-relation·
of two duration values x and
y is x < y iff s+x < s+y
for each qualified dateTime s
in the list below. These values for s cause the greatest deviations in the addition of
dateTimes and durations. Addition of durations to time instants is defined
in Adding durations to dateTimes (§H).
- 1696-09-01T00:00:00Z
- 1697-02-01T00:00:00Z
- 1903-03-01T00:00:00Z
- 1903-07-01T00:00:00Z
The following table shows the strongest relationship that can be determined
between example durations. The symbol <> means that the order relation is
indeterminate. Note that because of leap-seconds, a seconds field can vary
from 59 to 60. However, because of the way that addition is defined in
Adding durations to dateTimes (§H), they are still totally ordered.
| | Relation |
|---|
| P1Y | > P364D | <> P365D | | <> P366D | < P367D |
| P1M | > P27D | <> P28D | <> P29D | <> P30D | <> P31D | < P32D |
| P5M | > P149D | <> P150D | <> P151D | <> P152D | <> P153D | < P154D |
Implementations are free to optimize the computation of the ordering relationship. For example, the following table can be used to
compare durations of a small number of months against days.
| | Months | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | ... |
|---|
| Days | Minimum | 28 | 59 | 89 | 120 | 150 | 181 | 212 | 242 | 273 | 303 | 334 | 365 | 393 | ... |
|---|
| Maximum | 31 | 62 | 92 | 123 | 153 | 184 | 215 | 245 | 276 | 306 | 337 | 366 | 397 | ... |
|---|
↓
↓
3.2.7.5 Facet Comparison for durations
In comparing duration
values with , ,
and facet values
indeterminate comparisons should be considered as "false".
↓
↓
3.2.7.6 Totally ordered durations
Certain derived datatypes of durations can be guaranteed have a total order. For
this, they must have fields from only one row in the list below and the time zone
must either be required or prohibited.
- year, month
- day, hour, minute, second
For example, a datatype could be defined to correspond to the
[SQL] datatype Year-Month interval that required a four digit
year field and a two digit month field but required all other fields to be unspecified. This datatype could be defined as below and would have a total order.
<simpleType name='SQL-Year-Month-Interval'>
<restriction base='duration'>
<pattern value='P\p{Nd}{4}Y\p{Nd}{2}M'/>
</restriction>
</simpleType> ↓
3.2.8 dateTime
↓
[Definition:]
dateTime values
may be viewed as objects with integer-valued
year, month, day, hour and minute properties,
a decimal-valued second property,
and a boolean timezoned property.
Each such object also has one decimal-valued
method or computed property, timeOnTimeline,
whose value is always a decimal
number; the values are dimensioned in seconds,
the integer 0 is 0001-01-01T00:00:00 and the value
of timeOnTimeline for other dateTime
values is computed using the Gregorian algorithm
as modified for leap-seconds.
The timeOnTimeline values form two related
"timelines", one for timezoned
values and one for non-timezoned values.
Each timeline is a copy of the ·value space·
of pDecimal,
with integers given units of seconds.
↓
↑
dateTime represents
instants of time, optionally marked
with a particular timezone. Values representing
the same instant but having
different timezones are equal but not identical.
↑
↓
The ·value space· of
dateTime is closely related
to the dates and times described in ISO 8601.
For clarity, the text above specifies a
particular origin point for the timeline.
It should be noted, however, that schema processors need not expose the
timeOnTimeline value to schema users, and there is no requirement that a
timeline-based implementation use the particular origin described here in
its internal representation.
Other interpretations of the ·value space· which lead to the
same results (i.e., are isomorphic) are of course acceptable.
↓
↓
All timezoned times are Coordinated Universal Time
(·UTC·, sometimes called
"Greenwich Mean Time").
Other timezones indicated in lexical representations
are converted to ·UTC·
during conversion of literals to values.
"Local" or untimezoned times are presumed to be
the time in the timezone of some
unspecified locality as prescribed
by the appropriate legal authority;
currently there are no legally prescribed
timezones which are durations
whose magnitude is greater than 14 hours.
The value of each numeric-valued property
(other than timeOnTimeline) is limited to
the maximum value within the interval
determined by the next-higher property.
For example, the day value can never be 32,
and cannot even be 29 for month 02 and year 2002 (February 2002).
↓
↓
Note:
The date and time datatypes described in this recommendation were inspired
by
[ISO 8601]. '0001' is the lexical
representation of the year 1 of the Common Era
(1 CE, sometimes written "AD 1" or "1 AD"). There
is no year 0, and '0000' is not a valid lexical representation.
'-0001' is the lexical representation of the year 1 Before
Common Era (1 BCE, sometimes written "1 BC").
Those using this (1.0) version of this Recommendation to
represent negative years should be aware that the interpretation of lexical
representations beginning with a
'-' is likely to change in
subsequent versions.
[ISO 8601]
makes no mention of the year 0; in
[ISO 8601:1998 Draft Revision]
the form '0000' was disallowed and this recommendation disallows it as well.
However,
[ISO 8601:2000 Second Edition], which became
available just as we were completing version
1.0, allows the form '0000', representing the year
1 BCE. A number of external commentators
have also suggested that '0000' be
allowed, as the lexical representation for 1 BCE,
which is the normal usage in
astronomical contexts.
It is the intention of the XML Schema
Working Group to allow '0000' as a lexical representation in the
dateTime,
date,
gYear, and
gYearMonth datatypes in a subsequent version
of this Recommendation. '0000' will be the lexical representation of 1
BCE (which is a leap year), '-0001' will become the lexical representation of 2
BCE (not 1 BCE as in this (1.0) version), '-0002' of 3 BCE, etc.
↓
↓
Note: See the conformance note in
(§C) which
applies to this datatype as well.
↓
↑
3.2.8.1 Value Space
dateTime uses the
date/timeSevenPropertyModel, with no properties
except ·timezone·
permitted
to be absent. The ·timezone· property remains
·optional·.
Constraint: Day-of-month ValuesThe
·day· value
must be
no more than 30 if
·month·
is one of 4, 6, 9, or 11;
no more than 28
if
·month· is 2 and
·year· is not divisible 4,
or is divisible by 100 but not by 400;
and no more than 29 if
·month·
is 2 and
·year·
is divisible by 400, or by 4 but not by 100.
Constraint: Leap-second ValuesThe
·second· value
must be
less than 60 if
·timezone·
is
absent or if the remaining values
do not correspond to a dateTime at which a leap-second was introduced into
·UTC·
by the responsible authorities;
if the
hour and minute
in the specified timezone
allow a real leap-second then the value
must be less than 60 plus the number of
leap-seconds introduced on that date. (At
the time of publication of this specification, no
more than one leap-second has ever been introduced at
a timeand it appears unlikely that
this will ever happen.
No negative leap-seconds have been
introduced, but if any should be introduced in future,
"adding" that negative number will result
in a value limit of 59 or lower.)
Note: See the conformance note in
(§C) which
applies to the
·year· and
·second·
values of this datatype.
Equality and order are as prescribed
in The Seven-property Model (§D.2.1).
dateTime values are ordered
by their ·timeOnTimeline· value.
Note: Since the order of a
dateTime
value having a
·timezone·
with another value whose
·timezone· is
absent is determined
by imputing timezones of both +14:00
and –14:00 to the untimezoned value, many such
combinations will be
·incomparable· because the two imputed
timezones yield different orders.
Although
dateTime and other
types related to dates and times have only a partial order, it
is possible for datatypes derived from
dateTime to have
total orders, if they are restricted (e.g. using the
pattern facet) to the subset of values with, or
the subset of values without, timezones. Similar restrictions
on other date- and time-related types will similarly produce
totally ordered subtypes. Note, however, that
such restrictions do not affect the value shown, for a given
Simple Type Definition, in the
ordered facet.
Note: Order and equality are essentially the same for
dateTime in this version of this specification as
they were in version 1.0. However, since values
now distinguish timezones, equal
values with different
·timezone·s
are not
identical, and values with extreme
·timezone·s may no longer be equal
to any value with a smaller
·timezone·.
↑
↓
3.2.8.2 Lexical representation
The ·lexical space· of dateTime consists of
finite-length sequences of characters of the form:
'-'? yyyy '-' mm '-' dd 'T' hh ':' mm ':' ss ('.' s+)? (zzzzzz)?,
where
- '-'? yyyy is a
four-or-more digit optionally negative-signed
numeral that represents the year; if more than four digits, leading zeros
are prohibited, and '0000' is prohibited
(see the Note above (§3.2.8);
also note that a plus sign is not permitted);
- the remaining '-'s are separators between
parts of the date portion;
- the first mm is a two-digit
numeral that represents the month;
- dd is a two-digit numeral
that represents the day;
- 'T' is a separator indicating that time-of-day follows;
- hh is a two-digit numeral
that represents the hour; '24' is permitted if the
minutes and seconds represented are zero,
and the dateTime value so
represented is the first instant of the following day (the hour property of a
dateTime object in the
·value space· cannot have
a value greater than 23);
- ':' is a separator between parts of the time-of-day portion;
- the second mm is a
two-digit numeral that represents the minute;
- ss is a two-integer-digit numeral that represents the
whole seconds;
- '.' s+ (if present) represents the
fractional seconds;
- zzzzzz (if present) represents
the timezone (as described below).
For example, 2002-10-10T12:00:00-05:00 (noon on 10 October 2002, Central Daylight
Savings Time as well as Eastern Standard Time
in the U.S.) is 2002-10-10T17:00:00Z,
five hours later than 2002-10-10T12:00:00Z.
For further guidance on arithmetic with dateTimes and durations,
see Adding durations to dateTimes (§H).
↓
↓
3.2.8.3 Canonical representation
Except for trailing fractional zero digits in the seconds representation,
'24:00:00' time representations,
and timezone (for timezoned values), the mapping
from literals to values is one-to-one. Where there is more than
one possible representation, the canonical representation is as follows:
- The 2-digit numeral representing
the hour must not be '
24'; - The fractional second string, if present,
must not end in '
0'; - for timezoned values, the timezone must be represented with
'
Z' (All timezoned dateTime values are
·UTC·.).
↓
↑
3.2.8.4 Lexical Mappings
The lexical representations for dateTime are as follows:
Constraint: Day-of-month RepresentationsWithin a
dateTimeLexicalRep, a
dayFrag must not
begin with the digit '
3' or be '
29'
unless the value to
which it would map would satisfy the value constraint on
·day· values
("Constraint: Day-of-month Values") given above.
Constraint: Leap-second RepresentationsWithin a
dateTimeLexicalRep, a
secondFrag must not
begin with the digit '
6' unless the value to
which it would map, in conjunction with the rest of the values,
would satisfy the value constraint on leap-second values
("Constraint: Leap-second Values") given
above. Should a negative leap-second be declared, the
secondFrag is further limited to those which would
satisfy the even-tighter value constraint on
·second·.
The dateTimeLexicalRep production
is equivalent to this regular expression
once whitespace is removed.
\-?([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9])\-(0[1-9])|(1[0-2])\-(0[1-9])([12][0-9])|(3[01])
T(([01][0-9])|(2[0-3]):[0-5][0-9]:(([0-5][0-9])|(60))(.[0-9]+)?)|(24:00:00(.[0-9]+)?)
([+\-](0[0-9])|(1[0-4]):[0-5][0-9])?
Note that neither the dateTimeLexicalRep production
nor this regular
expression alone enforce the constraints on dateTimeLexicalRep given above.
The lexical mapping and canonical mapping
for dateTime are the following functions:
↑
↓
3.2.8.5 Timezones
Timezones are durations with (integer-valued) hour and minute properties
(with the hour magnitude limited to at most 14, and the minute magnitude
limited to at most 59, except that if the hour magnitude is 14, the minute
value must be 0); they may be both positive or both negative.
The lexical representation of a timezone is a string of the form:
(('+' | '-') hh ':' mm) | 'Z',
where
- hh is a two-digit numeral
(with leading zeros as required) that
represents the hours,
- mm is a two-digit
numeral that represents the minutes,
- '+' indicates a nonnegative duration,
- '-' indicates a nonpositive duration.
The mapping so defined is one-to-one, except that '+00:00',
'-00:00', and 'Z' all represent the same zero-length duration
timezone, ·UTC·; 'Z' is its canonical
representation.
When a timezone is added to a ·UTC·
dateTime, the result is the date
and time "in that timezone". For example, 2002-10-10T12:00:00+05:00 is
2002-10-10T07:00:00Z and 2002-10-10T00:00:00+05:00 is 2002-10-09T19:00:00Z.
↓
↓
3.2.8.6 Order relation on dateTime
dateTime value objects on either
timeline are totally ordered by their timeOnTimeline
values; between the two timelines, dateTime
value objects are ordered by their
timeOnTimeline values when their timeOnTimeline values differ by more than
fourteen hours, with those whose difference is a duration of 14 hours or less
being incomparable.
In general, the
·order-relation· on dateTime
is a partial order since there is no determinate relationship between certain
instants. For example, there is no determinate ordering between
(a) 2000-01-20T12:00:00 and (b) 2000-01-20T12:00:00Z. Based on
timezones currently in use, (c) could vary from 2000-01-20T12:00:00+12:00 to
2000-01-20T12:00:00-13:00. It is, however, possible for this range to expand or
contract in the future, based on local laws. Because of this, the following
definition uses a somewhat broader range of indeterminate values:
+14:00..-14:00.
The following definition uses the notation S[year] to represent the year
field of S, S[month] to represent the month field, and so on. The notation (Q
& "-14:00") means adding the timezone -14:00 to Q, where Q did not
already have a timezone. This is a
logical explanation of the process. Actual
implementations are free to optimize as
long as they produce the same results.
The ordering between two dateTimes P
and Q is defined by the following algorithm:
A.Normalize P and Q. That is, if there is a timezone present, but
it is not Z, convert it to Z using the addition operation defined in
Adding durations to dateTimes (§H)
- Thus 2000-03-04T23:00:00+03:00
normalizes to 2000-03-04T20:00:00Z
B. If P and Q either both have a time zone or both do not have a time
zone, compare P and Q field by field from the year field down to the
second field, and return a result as soon
as it can be determined. That is:
- For each i in {year, month, day, hour, minute, second}
- If P[i] and Q[i] are both
not specified, continue to the next i
- If P[i] is not specified
and Q[i] is, or vice versa, stop and return
P <> Q
- If P[i] < Q[i], stop and return P < Q
- If P[i] > Q[i], stop and return P > Q
- Stop and return P = Q
C.Otherwise, if P contains a time zone and Q does not, compare
as follows:
- P < Q if P < (Q with time zone +14:00)
- P > Q if P > (Q with time zone -14:00)
- P <> Q otherwise, that is, if (Q with time zone
+14:00) < P < (Q with time zone -14:00)
D. Otherwise, if P does not contain a time zone and Q does, compare
as follows:
- P < Q if (P with time zone -14:00) < Q.
- P > Q if (P with time zone +14:00) > Q.
- P <> Q otherwise, that is, if (P with
time zone +14:00) < Q < (P with time zone -14:00)
Examples:
| Determinate | Indeterminate |
|---|
| 2000-01-15T00:00:00
< 2000-02-15T00:00:00 | 2000-01-01T12:00:00 <>
1999-12-31T23:00:00Z |
| 2000-01-15T12:00:00
< 2000-01-16T12:00:00Z | 2000-01-16T12:00:00 <>
2000-01-16T12:00:00Z |
| | 2000-01-16T00:00:00
<> 2000-01-16T12:00:00Z |
↓
↓
3.2.8.7 Totally ordered dateTimes
Certain derived types from dateTime
can be guaranteed have a total order. To
do so, they must require that a specific
set of fields are always specified, and
that remaining fields (if any) are always unspecified. For example, the date
datatype without time zone is defined to contain exactly year, month, and day.
Thus dates without time zone have a total order among themselves.
↓
3.2.9 time
↓
[Definition:] time
represents an instant of time that recurs every day. The
·value space· of time is the space
of time of day values as defined in § 5.3 of
[ISO 8601]. Specifically, it is a set of zero-duration daily
time instances.
↓
↑
time
represents instants of time that recur at the same point in each
calendar day, or that occur in some arbitrary calendar day.
↑
↓
Since the lexical representation allows an optional time zone
indicator, time values are partially ordered because it may
not be able to determine the order of two values one of which has a
time zone and the other does not. The order relation on
time values is the
Order relation on dateTime (§3.2.8.6) using an arbitrary date. See also
Adding durations to dateTimes (§H). Pairs
of time values with or without time
zone indicators are totally ordered.
↓
↓
Note: See the conformance note in
(§C) which
applies to the seconds part of this datatype as well.
↓
↑
3.2.9.1 Value Space
time uses the date/timeSevenPropertyModel, with
·year·, ·month·,
and ·day· required
to be absent. ·timezone· remains
·optional·.
Constraint: Leap-second ValuesThe
·second· value
must be
less than 60 if
·timezone·
is
absent or if the remaining
values do not correspond to a time
at which, on some day, a leap-second has been introduced
into
·UTC· by the responsible
authorities;
if
the hour and minute
in the specified timezone
allow a real leap-second then the value
must be less than 60 plus the largest number of
leap-seconds introduced on any date. (At
the time of publication of this specification, no
more than one leap-second has ever been introduced at
a time and it appears unlikely that this will ever occur. No negative leap-seconds have been
introduced, but if any should be introduced in future,
"adding" that negative number will result
in a value limit of 59 or lower.)
Note: See the conformance note in
(§C) which
applies to the
·second· value of this datatype.
Issue (RQ-13i-time-copy):RQ-13 (time
zone crosses date line)The "seven property model" rewrite of
date/time datatype descriptions includes
a carefully crafted definition of order
that insures that for repeating datatypes (time, gDay, etc.), timezoned values
will be compared as though they are on the same "calendar day"
("local" property values) so that in any given timezone,
the days start at "local"
00:00:00 and end immediately before "local" 24:00:00.
Days in timezones other than Z do not run from 00:00:00Z to 24:00:00Z.
Equality and order are as prescribed in
The Seven-property Model (§D.2.1). time values
(points in time in an "arbitrary" day) are ordered
taking into account their ·timezone·.
A calendar ( or "local time") day with an early
timezone begins earlier than the same calendar day with a later
timezone. Since the timezones allowed spread over 28 hours,
there are timezone pairs for which a given calendar day in the two
timezones are totally disjoint—the earlier day ends before the
same day starts in the later timezone. The moments in time
represented by a single calendar day are spread over a 52-hour
interval, from the beginning of the day in the +14:00 timezone to the
end of that day in the –14:00 timezone.
Note: Since the order of a
time value
having a
·timezone·
with another value whose
·timezone·
is
absent is determined
by imputing timezones of both +14:00 and –14:00
to the untimezoned value, many such combinations will be
·incomparable· because the two imputed
timezones yield different orders. However,
for a given untimezoned value, there will
always be timezoned values at one or both
ends of the 52-hour interval that are
·comparable·
(because the interval of
·incomparability·
is only 24 hours wide).
Examples that show the difference from version 1.0 of this specification (see
Lexical Mappings (§3.2.9.4) for the notations):
- A day is a calendar (or "local
time") day in each timezone.
08:00:00+10:00 < 17:00:00+10:00
(just as 08:00:00Z has always been less than
17:00:00Z, but in version 1.0
08:00:00+10:00 > 17:00:00+10:00 )
- A time value in a calendar day with an early timezone
may precede every value in a later calendar day:00:00:00+01:00 is less than every value with
·timezone· Z
- A calendar day with a very early timezone may be completely
disjoint from a calendar day with a very late timezone:Each value with ·timezone·
+13:00 is less than every
value with ·timezone· –13:00
- time values do not always
convert to ·UTC·
in the same way as in 1.0, since a time
in a timezone may convert to
a ·UTC· time on
a different day (whereas time
conversions in version 1.0 "wrapped around"
by ignoring the day during conversion):
22:00:00Z > 03:00:00+05:00
(since 1971-12-31T03:00:00+05 is 1979-12-30T22:00:00Z,
not 1979-12-31T22:00:00Z); in the previous
version of this specification 22:00:00Z =
03:00:00+05:00 )
↑
↓
3.2.9.2 Lexical representation
The lexical representation for time is the left
truncated lexical representation for dateTime:
hh:mm:ss.sss with optional
following time zone indicator. For example,
to indicate 1:20 pm for Eastern
Standard Time which is 5 hours behind
Coordinated Universal Time (·UTC·),
one would write: 13:20:00-05:00. See also
ISO 8601 Date and Time Formats (§G).
↓
↓
3.2.9.3 Canonical representation
The canonical representation for time is defined
by prohibiting certain options from the
Lexical representation (§3.2.9.2).
Specifically, either the time zone must
be omitted or, if present, the time zone must be Coordinated Universal
Time (·UTC·) indicated by a "Z".
Additionally, the canonical representation for midnight is 00:00:00.
↓
↑
3.2.9.4 Lexical Mappings
The lexical representations for time
are "projections" of
those of dateTime, as follows:
Constraint: Leap-second RepresentationsAn
secondFrag must not begin with the
digit '
6' unless the value to
which it would map would satisfy the value
constraint on leap-second values given above.
The timeLexicalRep production
is equivalent to this
regular expression, once whitespace is
removed:
(([01][0-9])|(2[0-3]):[0-5][0-9]:[0-6][0-9])|(24:00:00)
(([01][0-9])|(2[0-3]):[0-5][0-9]:(([0-5][0-9])|(60))(.[0-9]+)?)|(24:00:00(.[0-9]+)?)
([+\-](0[0-9])|(1[0-4]):[0-5][0-9])?
Note that neither
the timeLexicalRep production
nor this regular
expression alone enforce the constraint
on timeLexicalRep given above.
The lexical mapping and canonical mapping
for time are the following functions:
↑
3.2.10 date
[Definition:]
↓The
·value space· of date
consists of top-open intervals of
exactly one day in length on the timelines of
dateTime, beginning on the beginning moment of each day (in
each timezone), i.e. '00:00:00', up
to but not including '24:00:00' (which is
identical with
'00:00:00'↓↑date
represents top-open intervals of exactly one day in length on the timelines of
dateTime, beginning on the beginning moment of each day (in
each timezone), up to but not including the beginning
moment↑ of the next day). For nontimezoned values, the top-open
intervals disjointly cover the nontimezoned timeline,
one per day. For timezoned
values, the intervals begin at every minute and therefore overlap.
↓
A "date object" is an object with year,
month, and day properties just like those
of dateTime objects, plus
an optional timezone-valued
timezone property. (As with values of dateTime timezones are a
special case of durations.)
Just as a dateTime object corresponds to a point on one of the
timelines, a date object corresponds to an interval on one
of the two timelines as just described.
↓
↓
Timezoned date values track the starting moment of their day, as
determined by their timezone; said timezone is generally recoverable for
canonical representations.
[Definition:]
The recoverable timezone is that duration which
is the result of subtracting the first moment (or any moment) of the timezoned
date from the first moment (or the
corresponding moment) ·UTC· on the
same date. ·recoverable timezone·s are
always durations between '+12:00' and
'-11:59'. This "timezone normalization"
(which follows automatically from the definition of the date
·value space·) is explained more in
Lexical representation (§3.2.10.2).
↓
↓
For example: the first moment of 2002-10-10+13:00 is 2002-10-10T00:00:00+13,
which is 2002-10-09T11:00:00Z, which is also the first moment of 2002-10-09-11:00.
Therefore 2002-10-10+13:00 is 2002-10-09-11:00;
they are the same interval.
↓
↓
Note:
For most timezones, either the first moment or last moment of the day (a
dateTime value, always
·UTC·) will have a
date portion
different from that of the
date itself!
However, noon of that
date (the midpoint of the interval) in that
(normalized) timezone will always have the same
date portion as the
date itself, even when that noon point in time is normalized to
·UTC·. For example,
2002-10-10-05:00 begins during 2002-10-09Z and 2002-10-10+05:00
ends during 2002-10-11Z, but noon of both 2002-10-10-05:00 and 2002-10-10+05:00
falls in the interval which is 2002-10-10Z.
↓
↑
3.2.10.1 Value Space
date uses the date/timeSevenPropertyModel, with
·hour·, ·minute·,
and ·second· required
to be absent. ·timezone· remains
·optional·.
Constraint: Day-of-month ValuesThe
·day· value
must be
no more than 30 if
·month·
is one of 4, 6, 9, or 11, no more than 28
if
·month· is 2 and
·year· is not divisble 4,
or is divisible by 100 but not by 400,
and no more than 29 if
·month·
is 2 and
·year·
is divisible by 400, or by 4 but not by 100.
Note: See the conformance note in
(§C) which
applies to the
·year·
value of this datatype.
Equality and order are as prescribed in
The Seven-property Model (§D.2.1).
Note: In version 1.0 of this specification,
date values
did not retain a timezone explicitly, but for timezones not too far from
·UTC· their timezone could be recovered based on
their value's first moment on the timeline. The
date/timeSevenPropertyModel retains all timezones.
Examples that show the difference from version 1.0 (see
Lexical Mappings (§3.2.10.4) for the notations):
- A day is a calendar (or "local
time") day in each timezone,
including the timezones outside of +12:00 through -11:59 inclusive:2000-12-12+13:00 < 2000-12-12+11:00
(just as 2000-12-12+12:00 has always been less than
2000-12-12+11:00, but in version 1.0
2000-12-12+13:00 > 2000-12-12+11:00 ,
since 2000-12-12+13:00's "recoverable
timezone" was –11:00)
- Similarly:2000-12-12+13:00 = 2000-12-13–11:00
(whereas under 1.0, as just
stated, 2000-12-12+13:00 = 2000-12-12–11:00)
↑
↓
3.2.10.2 Lexical representation
For the following discussion, let the
"date portion" of a dateTime
or date object be an object
similar to a dateTime or
date object, with similar year, month, and day properties, but no
others, having the same value for these properties as the original
dateTime or date object.
The ·lexical space· of
date consists of finite-length
sequences of characters of the form:
'-'? yyyy '-' mm '-' dd zzzzzz?
where the date and optional timezone are represented exactly the
same way as they are for dateTime. The first moment of the
interval is that represented by:
'-' yyyy '-' mm '-' dd 'T00:00:00' zzzzzz?
and the least upper bound of the interval is the timeline point represented
(noncanonically) by:
'-' yyyy '-' mm '-' dd 'T24:00:00' zzzzzz?.
Note:
The
·recoverable timezone· of a
date will always be
a duration between '+12:00' and
'11:59'. Timezone lexical representations, as
explained for
dateTime, can range from '+14:00' to '-14:00'.
The result is that literals of
dates with very large or very
negative timezones will map to a "normalized"
date value with a
·recoverable timezone·
different from that represented in the original
representation, and a matching difference
of +/- 1 day in the
date itself.
↓
↓
3.2.10.3 Canonical representation
Given a member of the date ·value space·, the
date portion of the canonical
representation (the entire representation
for nontimezoned values, and all but the
timezone representation for timezoned values)
is always the date portion
of the dateTime canonical
representation of the interval midpoint
(the dateTime representation,
truncated on the right to eliminate 'T' and all following characters).
For timezoned values, append the canonical
representation of the ·recoverable timezone·.
↓
↑
3.2.10.4 Lexical Mappings
The lexical representations for date
are "projections" of
those of dateTime, as follows:
Constraint: Day-of-month RepresentationsWithin a
dateLexicalRep,
a
dayFrag must not
begin with the digit '
3' or be '
29'
unless the value to
which it would map would satisfy the value constraint on
·day· values
("Constraint: Day-of-month Values") given above.
The dateLexicalRep production
is equivalent to this
regular expression:
\-?([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9])\-(0[1-9])|(1[0-2])\-([0-2][0-9])|(3[01])((+|\-)(0[0-9]|1[0-4]):[0-5][0-9])?
Note that neither
the dateLexicalRep production
nor this regular
expression alone enforce the constraint
on dateLexicalRep given above.
The lexical mapping and canonical mapping
for date are the following functions:
↑
3.2.11 gYearMonth
↓
[Definition:]
gYearMonth represents a specific gregorian month in a specific
gregorian year. The ·value space· of
gYearMonth is the set of Gregorian calendar months as defined
in § 5.2.1 of [ISO 8601]. Specifically, it is a set
of one-month long, non-periodic instances e.g. 1999-10 to represent the whole
month of 1999-10, independent of how many days this month has.
↓
↑
gYearMonth
represents specific whole Gregorian months in specific
Gregorian years.
↑
↓
Since the lexical representation allows an optional
time zone indicator, gYearMonth values are partially ordered
because it may not be possible to unequivocally determine the order of two
values one of which has a time zone and the other does not. If
gYearMonth values are considered as periods of time, the order
relation on gYearMonth values is the order relation on their
starting instants. This is discussed in Order relation on dateTime (§3.2.8.6).
See also Adding durations to dateTimes (§H). Pairs of
gYearMonth values with or without time zone indicators are
totally ordered.
↓
Note: Because month/year combinations in one calendar only rarely correspond
to month/year combinations in other calendars, values of this type
are not, in general, convertible to simple values corresponding to month/year
combinations in other calendars. This type should therefore be used
with caution in contexts where conversion to other calendars is desired.
↓
Note: See the conformance note in
(§C) which
applies to the year part of this datatype
as well.
↓
3.2.11.2 Lexical
↓representation↓↑Mappings↑
↓
The lexical representation for gYearMonth is the reduced
(right truncated) lexical representation for dateTime:
CCYY-MM. No left truncation is allowed. An optional following time
zone qualifier is allowed. To accommodate year values outside the
range from 0001 to 9999, additional digits
can be added to the left of this representation and a
preceding "-" sign is allowed.
↓
↑
The lexical representations for
gYearMonth are "projections" of
those of dateTime, as follows:
The gYearMonthLexicalRep is equivalent to this regular expression:
\-?([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9])\-(0[1-9])|(1[0-2])((+|\-)(0[0-9]|1[0-4]):[0-5][0-9])?
↑
↑
The lexical mapping and canonical mapping
for gYearMonth are the following functions:
↑
3.2.12 gYear
↓
[Definition:]
gYear represents a
gregorian calendar year. The ·value space· of
gYear is the set of Gregorian calendar years as defined in
§ 5.2.1 of [ISO 8601]. Specifically, it is a set of one-year
long, non-periodic instances
e.g. lexical 1999 to represent the whole year 1999, independent of
how many months and days this year has.
↓
↑
gYear
represents Gregorian calendar years.
↑
↓
Since the lexical representation allows an optional time zone
indicator, gYear values are partially ordered because it may
not be possible to unequivocally determine
the order of two values one of which has a
time zone and the other does not. If
gYear values are considered as periods of time, the order relation
on gYear values is the order relation on their starting instants.
This is discussed in Order relation on dateTime (§3.2.8.6). See also
Adding durations to dateTimes (§H). Pairs of
gYear values with or without time
zone indicators are totally ordered.
↓
Note:
Because years in one calendar only rarely correspond to years
in other calendars, values of this type
are not, in general, convertible to simple values corresponding to years
in other calendars. This type should therefore be used with caution
in contexts where conversion to other calendars is desired.
↓
Note: See the conformance note in
(§C) which
applies to the year part of this datatype
as well.
↓
↑
3.2.12.1 Value Space
gYear uses the date/timeSevenPropertyModel, with
·month·, ·day·, ·hour·,
·minute·, and ·second· required
to be absent. ·timezone· remains
·optional·.
Note: See the conformance note in
(§C) which
applies to the
·year· value of this datatype.
Equality and order are as prescribed in
The Seven-property Model (§D.2.1).
Note: In version 1.0 of this specification,
gYear
values did not
retain a timezone explicitly, but timezones not too far from
·UTC·
could be recovered based on the
gYear
value's first moment on the timeline. The
date/timeSevenPropertyModel simply retains all timezones.
An example that shows the difference from version 1.0 (see
Lexical
↓representation↓↑Mappings↑ (§3.2.12.2) for the notations):
- A day is a calendar (or "local time") day in
each timezone, including the timezones outside of +12:00 through
–11:59 inclusive:2000+13:00 < 2000+11:00
(just as 2000+12:00 has always been less than 2000+11:00,
but in version 1.0 2000+13:00 >
2000+11:00 , since 2000+13:00's "recoverable
timezone" was –11:00)
↑
3.2.12.2 Lexical
↓representation↓↑Mappings↑
↓
The lexical representation for gYear is the reduced (right
truncated) lexical representation for dateTime: CCYY.
No left truncation is allowed. An optional following time
zone qualifier is allowed as for dateTime. To
accommodate year values outside the range from 0001 to 9999, additional
digits can be added to the left of this representation and a preceding
"-" sign is allowed.
↓
↑
The lexical representations for
gYear are "projections" of
those of dateTime, as follows:
The gYearLexicalRep is equivalent to this regular expression:
\-?([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9])((+|\-)(0[0-9]|1[0-4]):[0-5][0-9])?
↑
↑
The lexical mapping and canonical mapping
for gYear are the following functions:
↑
3.2.13 gMonthDay
↓
[Definition:]
gMonthDay is a gregorian date that recurs, specifically a day of
the year such as the third of May. Arbitrary recurring dates are not
supported by this datatype. The ·value space· of
gMonthDay is the set of calendar
dates, as defined in § 3 of [ISO 8601]. Specifically,
it is a set of one-day long, annually periodic instances.
↓
↑
gMonthDay represents whole calendar
days that recur at the same point in each calendar year, or that occur
in some arbitrary calendar year.
↑
↑
This datatype can be used, for example, to record
birthdays; an instance of the datatype could be used to say that
someone's birthday occurs on the 14th of September every year.
↑
↓
Since the lexical representation allows an optional time zone
indicator, gMonthDay values are partially ordered because it may
not be possible to unequivocally determine the order of two values one of which has a
time zone and the other does not. If
gMonthDay values are considered as periods of time,
in an arbitrary leap year, the order relation
on gMonthDay values is the order relation on their starting instants.
This is discussed in Order relation on dateTime (§3.2.8.6). See also
Adding durations to dateTimes (§H). Pairs of gMonthDay values with or without time zone indicators are totally ordered.
↓
Note:
Because day/month combinations in one calendar only rarely correspond
to day/month combinations in other calendars, values of this type do not,
in general, have any straightforward or intuitive representation
in terms of most other calendars. This type should therefore be
used with caution in contexts where conversion to other calendars
is desired.
↑
3.2.13.1 Value Space
gMonthDay uses the date/timeSevenPropertyModel, with
·year·, ·hour·, ·minute·, and ·second· required
to be absent. ·timezone· remains
·optional·.
Constraint: Day-of-month ValuesThe
·day· value
must be no more than 30 if
·month·
is one of 4, 6, 9, or 11, and no more than 29 if
·month· is 2.
Equality and order are as prescribed in
The Seven-property Model (§D.2.1).
Note: In version 1.0 of this specification,
gMonthDay values
did not retain a timezone explicitly, but for timezones not too far from
·UTC· their timezone could be recovered based on
their value's first moment on the timeline. The
date/timeSevenPropertyModel retains all timezones.
An example that shows the difference from version 1.0 (see
Lexical
↓representation↓↑Mappings↑ (§3.2.13.2) for the notations):
- A day is a calendar (or "local time") day in each timezone,
including the timezones outside of +12:00 through –11:59 inclusive:--12-12+13:00 < --12-12+11:00
(just as --12-12+12:00 has always been less than
--12-12+11:00, but in version 1.0
--12-12+13:00 > --12-12+11:00 , since
--12-12+13:00's "recoverable
timezone" was –11:00)
↑
3.2.13.2 Lexical
↓representation↓↑Mappings↑
↓
The lexical representation for gMonthDay is the left
truncated lexical representation for date: --MM-DD.
An optional following time
zone qualifier is allowed as for date.
No preceding sign is allowed. No other formats are
allowed. See also ISO 8601 Date and Time Formats (§G).
↓
↑
The lexical representations for
gMonthDay are "projections"
of those of dateTime, as follows:
Constraint: Day-of-month RepresentationsWithin a
gMonthDayLexicalRep, a
dayFrag must not
begin with the digit '
3' or be '
29'
unless the value to
which it would map would satisfy the value constraint on
·day· values
("Constraint: Day-of-month Values") given above.
The gMonthDayLexicalRep is equivalent to this regular
expression:
\-\-(0[1-9])|(1[0-2])\-([0-2][0-9])|(3[01])((+|\-)(0[0-9]|1[0-4]):[0-5][0-9])?
Note that neither
the gMonthDayLexicalRep production
nor this regular
expression alone enforce the constraint
on gMonthDayLexicalRep given above.
↑
↓
This datatype can be used to represent a
specific day in a month. To say, for example, that my birthday occurs
on the 14th of September ever year.
↓
↑
The lexical mapping and canonical mapping
for gMonthDay are the following functions:
↑
3.2.14 gDay
↓
[Definition:]
gDay is a gregorian day that recurs, specifically a day
of the month such as the 5th of the month. Arbitrary recurring days
are not supported by this datatype. The ·value space·
of gDay is the space of a set of calendar
dates as defined in § 3 of [ISO 8601]. Specifically,
it is a set of one-day long, monthly periodic instances.
↓
↑[Definition:] gDay
represents
whole days within an arbitrary month—days that recur at the same
point in each (Gregorian) month.↑ This datatype ↓can
be↓↑is↑ used to represent a specific day of the month.
To ↓say, for example, that I get my paycheck↓↑indicate, for example, that an employee gets a paycheck↑ on the 15th of each month. ↑(Obviously, days
beyond 28 cannot occur in all months; they are nonetheless permitted, up to 31.)↑
↓
Since the lexical representation allows an optional time zone
indicator, gDay values are partially ordered because it may
not be possible to unequivocally determine the order of two values one of
which has a time zone and the other does not. If
gDay values are considered as periods of time,
in an arbitrary month that has 31 days,
the order relation
on gDay values is the order relation on their starting instants.
This is discussed in Order relation on dateTime (§3.2.8.6). See also
Adding durations to dateTimes (§H). Pairs of gDay
values with or without time zone indicators are totally ordered.
↓
Note: Because days in one calendar only rarely
correspond to days in other calendars,
↑gday ↑values↓
of this type↓ do not, in general, have any straightforward or
intuitive representation in terms of most
↓other↓↑non-Gregorian↑
calendars.
↓This
type↓↑gday↑
should therefore be used with caution in contexts where conversion to
other calendars is desired.
↑
3.2.14.1 Value Space
gDay uses the date/timeSevenPropertyModel, with
·year·, ·month·,
·hour·, ·minute·,
and ·second· required to be
absent. ·timezone· remains
·optional· and ·day·
must be between 1 and 31 inclusive.
Equality and order are as prescribed in
The Seven-property Model (§D.2.1). Since gDay
values (days) are ordered by their first moments, it is possible
for apparent anomalies to appear in the order when
·timezone· values
differ by at least 24
hours. (It is possible for ·timezone·
values to differ by up to 28 hours.)
Examples that may appear anomalous (see Lexical Mappings (§3.2.14.3) for the notations):
- ---15 < ---16 , but ---15–13:00 > ---16+13:00
- ---15–11:00 = ---16+13:00
- ---15–13:00 <> ---16 ,
because ---15–13:00 > ---16+14:00
and ---15–13:00 < 16–14:00
Note:
Timezones do not cause wrap-around at the end of the month:
the last day of a
given month in timezone –13:00 may start after the first
day of the next month in timezone +13:00, as
measured on the global timeline,
but nonetheless
---01+13:00 < ---31–13:00 .
↑
↓
3.2.14.2 Lexical
representation
The lexical representation for gDay is the left
truncated lexical representation for date: ---DD .
An optional following time
zone qualifier is allowed as for date. No preceding sign is
allowed. No other formats are allowed. See also ISO 8601 Date and Time Formats (§G).
↓
↑
3.2.14.3 Lexical Mappings
The lexical representations for gDay are
"projections"
of those of dateTime, as follows:
The gDayLexicalRep is equivalent to this regular expression:
\-\-\-([0-2][0-9]|3[01])((+|\-)(0[0-9]|1[0-4]):[0-5][0-9])?
The lexical mapping and canonical mapping for gDay are defined as follows:
↑
3.2.15 gMonth
↓
[Definition:]
gMonth is a gregorian month that recurs every year.
The ·value space·
of gMonth is the space of a set of calendar
months as defined in § 3 of [ISO 8601]. Specifically,
it is a set of one-month long, yearly periodic instances.
↓
↓This datatype can be used to represent a
specific month. To say, for example, that Thanksgiving falls in the month of
November.↓↑gMonth
represents whole (Gregorian) months
within an arbitrary year—months that recur at the same point in
each year. It might be used, for example, to say what
month annual Thanksgiving celebrations fall in different countries
(--11 in the United States, --10 in Canada, and possibly other months in
other countries).↑
↓
Since the lexical representation allows an optional time zone
indicator, gMonth values are partially ordered because it may
not be possible to unequivocally determine the order of two values one of which has a
time zone and the other does not. If
gMonth values are considered as periods of time, the order relation
on gMonth is the order relation on their starting instants.
This is discussed in Order relation on dateTime (§3.2.8.6). See also
Adding durations to dateTimes (§H). Pairs of gMonth
values with or without time zone indicators are totally ordered.
↓
Note:
Because months in one calendar only rarely correspond
to months in other calendars, values of this type do not,
in general, have any straightforward or intuitive representation
in terms of most other calendars. This type should therefore be
used with caution in contexts where conversion to other calendars
is desired.
↑
3.2.15.1 Value Space
gMonth uses the date/timeSevenPropertyModel, with
·year·, ·day·, ·hour·, ·minute·, and ·second· required
to be absent. ·timezone· remains
·optional·.
Equality and order are as prescribed in
The Seven-property Model (§D.2.1).
Note: In version 1.0 of this specification,
gMonth values
did not retain a timezone explicitly, but for timezones not too far from
·UTC· their timezone could be recovered based on
their value's first moment on the timeline. The
date/timeSevenPropertyModel retains all timezones.
An example that shows the difference from version 1.0 (see
Lexical
↓representation↓↑Mappings↑ (§3.2.15.2) for the notations):
- A month is a calendar (or "local time") month in each timezone,
including the timezones outside of +12:00 through –11:59 inclusive:--12+13:00 < --12+11:00
(just as --12+12:00 has always been less than --12+11:00, but in version 1.0
--12+13:00 > --12+11:00 , since --12+13:00's "recoverable
timezone" was –11:00)
↑
3.2.15.2 Lexical
↓representation↓↑Mappings↑
↓
The lexical representation for gMonth is the left
and right truncated lexical representation for date: --MM.
An optional following time
zone qualifier is allowed as for date. No preceding sign is
allowed. No other formats are allowed. See also ISO 8601 Date and Time Formats (§G).
↓
↑
The lexical representations for gMonth are "projections" of
those of dateTime, as follows:
The gMonthLexicalRep is equivalent to this regular expression:
\-\-(0[1-9])|(1[0-2])((+|\-)(0[0-9]|1[0-4]):[0-5][0-9])?
↑
↑
The lexical mapping and canonical mapping
for gMonth are defined as follows:
↑
3.2.16 hexBinary
[Definition:]
hexBinary represents
arbitrary hex-encoded binary data. The ·value space· of
hexBinary is the set of finite-length sequences of binary
octets.
3.2.16.1 Lexical Representation
hexBinary has a lexical representation where
each binary octet is encoded as a character tuple, consisting of two
hexadecimal digits ([0-9a-fA-F]) representing the octet code. For example,
"0FB7" is a hex encoding for the 16-bit integer 4023
(whose binary representation is 111110110111).
3.2.16.2 Canonical Representation
The canonical representation for hexBinary is defined
by prohibiting certain options from the
Lexical Representation (§3.2.16.1). Specifically, the lower case
hexadecimal digits ([a-f]) are not allowed.
3.2.17 base64Binary
[Definition:]
base64Binary
represents Base64-encoded arbitrary binary data. The ·value space· of
base64Binary is the set of finite-length sequences of binary
octets. For base64Binary data the
entire binary stream is encoded using the Base64
Alphabet in
[RFC 2045].
The lexical forms of base64Binary values are limited to the 65 characters
of the Base64 Alphabet defined in [RFC 2045], i.e., a-z,
A-Z, 0-9, the plus sign (+), the forward slash (/) and the
equal sign (=), together with the characters defined in [XML] as white space.
No other characters are allowed.
For compatibility with older mail gateways, [RFC 2045] suggests that
base64 data should have lines limited to at most 76 characters in length. This
line-length limitation is not mandated in the lexical forms of base64Binary
data and must not be enforced by XML Schema processors.
The lexical space of base64Binary is given by the following grammar
(the notation is that used in [XML]); legal lexical forms must match
the Base64Binary production.
Base64Binary ::= ((B64S B64S B64S B64S)*
((B64S B64S B64S B64) |
(B64S B64S B16S '=') |
(B64S B04S '=' #x20? '=')))?
B64S ::= B64 #x20?
B16S ::= B16 #x20?
B04S ::= B04 #x20?
B04 ::= [AQgw]
B16 ::= [AEIMQUYcgkosw048]
B64 ::= [A-Za-z0-9+/]
Note that this grammar requires the number of non-whitespace characters in the lexical
form to be a multiple of four, and for equals signs to appear only at the end of the
lexical form; strings which do not meet these constraints are not legal lexical forms
of base64Binary because they cannot successfully be decoded by base64
decoders.
Note: The above definition of the lexical space is more restrictive than that
given in
[RFC 2045] as regards whitespace -- this is not an issue
in practice. Any string compatible with the RFC can occur in
an element or attribute validated by this type, because the
·whiteSpace· facet of this type is fixed
to
collapse, which means that all leading and trailing whitespace
will be stripped, and all internal whitespace collapsed to single space
characters,
before the above grammar is enforced.
The canonical lexical form of a base64Binary data value is the base64
encoding of the value which matches the Canonical-base64Binary production in the following
grammar:
Canonical-base64Binary ::= (B64
B64 B64 B64)*
((B64 B64 B16 '=') | (B64 B04 '=='))?
Note: For some values the canonical form defined above does not conform to
[RFC 2045], which requires
breaking with linefeeds at appropriate intervals.
The length of a base64Binary value is the number of octets it contains.
This may be calculated from the lexical form by removing whitespace and padding characters
and performing the calculation shown in the pseudo-code below:
lex2 := killwhitespace(lexform) -- remove whitespace characters
lex3 := strip_equals(lex2) -- strip padding characters at end
length := floor (length(lex3) * 3 / 4) -- calculate length
Note on encoding: [RFC 2045] explicitly references US-ASCII encoding. However,
decoding of base64Binary data in an XML entity is to be performed on the
Unicode characters obtained after character encoding processing as specified by
[XML]
3.2.18 anyURI
[Definition:]
anyURI represents a Uniform Resource Identifier Reference
(URI). An anyURI value can be absolute or relative, and may
have an optional fragment identifier (i.e., it may be a URI Reference). This
type should be used to specify the intention that the value fulfills
the role of a URI as defined by [RFC 2396], as amended by
[RFC 2732].
The mapping from anyURI values to URIs is as
defined by the URI reference escaping procedure
defined in
Section 5.4 Locator Attribute
of [XML Linking Language] (see also
Section ↓8↓↑7↑
Character Encoding in URI References
of [Character Model]). This means
that a wide range of internationalized resource identifiers can be specified
when an anyURI is called for, and still be understood as
URIs per [RFC 2396], as amended by [RFC 2732],
where appropriate to identify resources.
Note:
Section 5.4
Locator Attribute
of
[XML Linking Language] requires that relative URI references be absolutized
as defined in
[XML Base] before use. This is an XLink-specific
requirement and is not appropriate for XML Schema, since neither the
·lexical space· nor the
·value space·
of the
anyURI type are restricted to absolute URIs. Accordingly
absolutization must not be performed by schema processors as part of schema
validation.
Note:
Each URI scheme imposes specialized syntax rules for URIs in
that scheme, including restrictions on the syntax of allowed
fragment
identifiers. Because it is
impractical for processors to check that a value is a
context-appropriate URI reference, this specification follows the
lead of
[RFC 2396] (as amended by
[RFC 2732])
in this matter: such rules and restrictions are not part of type validity
and are not checked by
·minimally conforming· processors.
Thus in practice the above definition imposes only very modest obligations
on
·minimally conforming· processors.
3.2.18.1 Lexical representation
The ·lexical space· of anyURI is
finite-length character sequences which, when the algorithm defined in
Section 5.4 of [XML Linking Language] is applied to them, result in strings
which are legal URIs according to [RFC 2396], as amended by
[RFC 2732].
Note:
Spaces are, in principle, allowed in the
·lexical space·
of
anyURI, however, their use is highly discouraged
(unless they are encoded by %20).
3.2.20 NOTATION
[Definition:]
NOTATION
represents the NOTATION attribute
type from [XML]. The ·value space·
of NOTATION is the set of QNames
of notations declared in the current schema.
The ·lexical space· of NOTATION is the set
of all names of notations
declared in the current schema (in the form of QNames).
Schema Component Constraint: enumeration facet value required for NOTATION
It is an
·error· for
NOTATION
to be used directly in a schema. Only datatypes that are
·derived· from
NOTATION by
specifying a value for
·enumeration· can be used
in a schema.
For compatibility (see Terminology (§1.5)) NOTATION
should be used only on attributes
and should only be used in schemas with no
target namespace.
3.3 Derived datatypes
This section gives conceptual definitions for all
·built-in· ·derived· datatypes
defined by this specification. The XML representation used to define
·derived· datatypes (whether
·built-in· or ·user-derived·) is
given in section XML Representation of Simple Type Definition Schema Components (§4.1.2) and the complete
definitions of the ·built-in·
·derived· datatypes are provided in Appendix A
Schema for Datatype Definitions (normative) (§A).
3.3.1 normalizedString
[Definition:]
normalizedString
represents white space normalized strings.
The ·value space· of normalizedString is the
set of strings that do not
contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters.
The ·lexical space· of normalizedString is the
set of strings that do not
contain the carriage return (#xD),
line feed (#xA)
nor tab (#x9) characters.
The ·base type· of normalizedString is string.
3.3.1.2 Derived datatypes
The following ·built-in·
datatypes are ·derived· from
normalizedString:
3.3.2 token
[Definition:]
token
represents tokenized strings.
The ·value space· of token is the
set of strings that do not
contain the
carriage return (#xD),
line feed (#xA) nor tab (#x9) characters, that have no
leading or trailing spaces (#x20) and that have no internal sequences
of two or more spaces.
The ·lexical space· of token is the
set of strings that do not contain the
carriage return (#xD),
line feed (#xA) nor tab (#x9) characters, that have no
leading or trailing spaces (#x20) and that have no internal sequences
of two or more spaces.
The ·base type· of token is normalizedString.
3.3.13 integer
[Definition:]
integer is
·derived· from decimal by fixing the
value of ·fractionDigits· to be 0 and
disallowing the trailing decimal point.
This results in the standard
mathematical concept of the integer numbers. The
·value space· of integer is the infinite
set {...,-2,-1,0,1,2,...}. The ·base type· of
integer is decimal.
3.3.13.1 Lexical representation
integer has a lexical representation consisting of a finite-length sequence
of decimal digits (#x30-#x39) with an optional leading sign. If the sign is omitted,
"+" is assumed. For example: -1, 0, 12678967543233, +100000.
3.3.13.2 Canonical representation
The canonical representation for integer is defined
by prohibiting certain options from the
Lexical representation (§3.3.13.1). Specifically, the preceding optional "+" sign is prohibited and leading zeroes are prohibited.
3.3.14 nonPositiveInteger
[Definition:]
nonPositiveInteger is ·derived· from
integer by setting the value of
·maxInclusive· to be 0. This results in the
standard mathematical concept of the non-positive integers.
The ·value space· of nonPositiveInteger
is the infinite set {...,-2,-1,0}. The ·base type·
of nonPositiveInteger is integer.
3.3.14.1 Lexical representation
nonPositiveInteger has a lexical representation consisting of
an optional preceding sign
followed by a finite-length sequence of decimal digits (#x30-#x39).
The sign may be "+" or may be omitted only for
lexical forms denoting zero; in all other lexical forms, the negative
sign ("-") must be present.
For example: -1, 0, -12678967543233, -100000.
3.3.14.2 Canonical representation
The canonical representation for nonPositiveInteger is defined
by prohibiting certain options from the
Lexical representation (§3.3.14.1).
In the canonical form for zero, the sign must be
omitted. Leading zeroes are prohibited.
3.3.14.4 Derived datatypes
The following ·built-in·
datatypes are ·derived· from
nonPositiveInteger:
3.3.15 negativeInteger
[Definition:]
negativeInteger is ·derived· from
nonPositiveInteger by setting the value of
·maxInclusive· to be -1. This results in the
standard mathematical concept of the negative integers. The
·value space· of negativeInteger
is the infinite set {...,-2,-1}. The ·base type·
of negativeInteger is nonPositiveInteger.
3.3.15.1 Lexical representation
negativeInteger has a lexical representation consisting of
a negative sign ("-") followed by a finite-length
sequence of decimal digits (#x30-#x39). For example: -1, -12678967543233, -100000.
3.3.15.2 Canonical representation
The canonical representation for negativeInteger is defined
by prohibiting certain options from the
Lexical representation (§3.3.15.1). Specifically, leading zeroes are prohibited.
3.3.16 long
[Definition:]
long is
·derived· from integer by setting the
value of ·maxInclusive· to be 9223372036854775807
and ·minInclusive· to be -9223372036854775808.
The ·base type· of long is
integer.
3.3.16.1 Lexical representation
long has a lexical representation consisting
of an optional sign followed by a finite-length
sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed.
For example: -1, 0,
12678967543233, +100000.
3.3.16.2 Canonical representation
The canonical representation for long is defined
by prohibiting certain options from the
Lexical representation (§3.3.16.1). Specifically, the
the optional "+" sign is prohibited and leading zeroes are prohibited.
3.3.17 int
[Definition:]
int
is ·derived· from long by setting the
value of ·maxInclusive· to be 2147483647 and
·minInclusive· to be -2147483648. The
·base type· of int is long.
3.3.17.1 Lexical representation
int has a lexical representation consisting
of an optional sign followed by a finite-length
sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed.
For example: -1, 0,
126789675, +100000.
3.3.17.2 Canonical representation
The canonical representation for int is defined
by prohibiting certain options from the
Lexical representation (§3.3.17.1). Specifically, the
the optional "+" sign is prohibited and leading zeroes are prohibited.
3.3.18 short
[Definition:]
short is
·derived· from int by setting the
value of ·maxInclusive· to be 32767 and
·minInclusive· to be -32768. The
·base type· of short is
int.
3.3.18.1 Lexical representation
short has a lexical representation consisting
of an optional sign followed by a finite-length sequence of decimal
digits (#x30-#x39). If the sign is omitted, "+" is assumed.
For example: -1, 0, 12678, +10000.
3.3.18.2 Canonical representation
The canonical representation for short is defined
by prohibiting certain options from the
Lexical representation (§3.3.18.1). Specifically, the
the optional "+" sign is prohibited and leading zeroes are prohibited.
3.3.19 byte
[Definition:]
byte
is ·derived· from short
by setting the value of ·maxInclusive· to be 127
and ·minInclusive· to be -128.
The ·base type· of byte is
short.
3.3.19.1 Lexical representation
byte has a lexical representation consisting
of an optional sign followed by a finite-length
sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed.
For example: -1, 0,
126, +100.
3.3.19.2 Canonical representation
The canonical representation for byte is defined
by prohibiting certain options from the
Lexical representation (§3.3.19.1). Specifically, the
the optional "+" sign is prohibited and leading zeroes are prohibited.
3.3.20 nonNegativeInteger
[Definition:]
nonNegativeInteger is ·derived· from
integer by setting the value of
·minInclusive· to be 0. This results in the
standard mathematical concept of the non-negative integers. The
·value space· of nonNegativeInteger
is the infinite set {0,1,2,...}. The ·base type· of
nonNegativeInteger is integer.
3.3.20.1 Lexical representation
nonNegativeInteger has a lexical representation consisting of
an optional sign followed by a finite-length
sequence of decimal digits (#x30-#x39). If the sign is omitted,
the positive sign ("+") is assumed.
If the sign is present, it must be "+" except for lexical forms
denoting zero, which may be preceded by a positive ("+") or a negative ("-") sign.
For example:
1, 0, 12678967543233, +100000.
3.3.20.2 Canonical representation
The canonical representation for nonNegativeInteger is defined
by prohibiting certain options from the
Lexical representation (§3.3.20.1). Specifically, the
the optional "+" sign is prohibited and leading zeroes are prohibited.
3.3.20.4 Derived datatypes
The following ·built-in·
datatypes are ·derived· from
nonNegativeInteger:
3.3.21 unsignedLong
[Definition:]
unsignedLong is ·derived· from
nonNegativeInteger by setting the value of
·maxInclusive· to be 18446744073709551615.
The ·base type· of unsignedLong is
nonNegativeInteger.
3.3.21.1 Lexical representation
unsignedLong has a lexical representation consisting
of a finite-length sequence of decimal digits (#x30-#x39).
For example: 0,
12678967543233, 100000.
3.3.21.2 Canonical representation
The canonical representation for unsignedLong is defined
by prohibiting certain options from the
Lexical representation (§3.3.21.1). Specifically,
leading zeroes are prohibited.
3.3.22 unsignedInt
[Definition:]
unsignedInt is ·derived· from
unsignedLong by setting the value of
·maxInclusive· to be 4294967295. The
·base type· of unsignedInt is
unsignedLong.
3.3.22.1 Lexical representation
unsignedInt has a lexical representation consisting
of a finite-length
sequence of decimal digits (#x30-#x39). For example: 0,
1267896754, 100000.
3.3.22.2 Canonical representation
The canonical representation for unsignedInt is defined
by prohibiting certain options from the
Lexical representation (§3.3.22.1). Specifically,
leading zeroes are prohibited.
3.3.23 unsignedShort
[Definition:]
unsignedShort is ·derived· from
unsignedInt by setting the value of
·maxInclusive· to be 65535. The
·base type· of unsignedShort is
unsignedInt.
3.3.23.1 Lexical representation
unsignedShort has a lexical representation consisting
of a finite-length
sequence of decimal digits (#x30-#x39).
For example: 0,
12678, 10000.
3.3.23.2 Canonical representation
The canonical representation for unsignedShort is defined
by prohibiting certain options from the
Lexical representation (§3.3.23.1). Specifically, the
leading zeroes are prohibited.
3.3.23.4 Derived datatypes
The following ·built-in·
datatypes are ·derived· from
unsignedShort:
3.3.24 unsignedByte
[Definition:]
unsignedByte is ·derived· from
unsignedShort by setting the value of
·maxInclusive· to be 255. The
·base type· of unsignedByte is
unsignedShort.
3.3.24.1 Lexical representation
unsignedByte has a lexical representation consisting
of a finite-length
sequence of decimal digits (#x30-#x39).
For example: 0,
126, 100.
3.3.24.2 Canonical representation
The canonical representation for unsignedByte is defined
by prohibiting certain options from the
Lexical representation (§3.3.24.1). Specifically,
leading zeroes are prohibited.
3.3.25 positiveInteger
[Definition:]
positiveInteger is ·derived· from
nonNegativeInteger by setting the value of
·minInclusive· to be 1. This results in the standard
mathematical concept of the positive integer numbers.
The ·value space· of positiveInteger
is the infinite set {1,2,...}. The ·base type· of
positiveInteger is nonNegativeInteger.
3.3.25.1 Lexical representation
positiveInteger has a lexical representation consisting
of an optional positive sign ("+") followed by a finite-length
sequence of decimal digits (#x30-#x39).
For example: 1, 12678967543233, +100000.
3.3.25.2 Canonical representation
The canonical representation for positiveInteger is defined
by prohibiting certain options from the
Lexical representation (§3.3.25.1). Specifically, the
optional "+" sign is prohibited and leading zeroes are prohibited.