RPCL Language Definition
There follows a Backus&hyphen.Naur Form (BNF) definition of the RPC
language, RPCL Version 3.0. This is a reference definition and should
be used to solve any ambiguity or error that could arise when writing
in RPCL. Reserved keywords are in upper case. Words inside angle brackets
are productions: that is, they may be replaced by the part on the
right of the '::=' of their own definition. The sign '|' means 'exclusive
or', that is one form or the other may be used.
<![CDATA[
<rpcl_program> ::= PACKAGE <ident> IS
{ <type_dec> ; }*
{ <other_dec> ; }*
END <ident> ;
<type_dec> ::= TYPE <ident> IS <type>
| <pragma>
<other_dec> ::= PROCEDURE <ident> <formal_params>
| FUNCTION <ident> <formal_params> RETURN <simple_type>
| <pragma>
<formal_params> ::= ( <formal_def> { ; <formal_def> }* )
| <void>
<formal_def> ::= <identlist> : <direction> <type>
<direction> ::= IN
| OUT
| IN OUT
<pragma> | PRAGMA EXTERNAL_MARSHALLING( <identlist> );
| PRAGMA CONCURRENT ( <identlist> )
| PRAGMA CAST ( <identlist> )
| PRAGMA TIMEOUT ( <ident> , <number> )
| PRAGMA CALL_STATUS ( <ident> , <ident> )
<identlist> ::= <ident> {, <ident>}*
<type> ::= <simple_type>
| <structured_type>
| ACCESS <subtype>
<subtype> ::= <ident>
| <simple type>
<simple_type> ::= RPC_CHAR
| RPC_BYTE
| RPC_SHORT
| RPC_INTEGER
| RPC_LONG
| RPC_REAL32
| RPC_REAL48
| RPC_REAL64
| RPC_REAL128
<structured_type>::= ARRAY (range { , <range> }*) OF <subtype>
| RECORD { <identlist> : <subtype> }* END RECORD
| SEQUENCE (index) OF <subtype>
| STRING ( [index] )
| SUBSTRING ( [index] )
<range> ::= [index] .. [index]
<number> ::= < A number in 1 .. 65536>
<ident> ::= < A Pascal&hyphen.like identifier>
]]>Where
<![CDATA[
::= means "may be composed of"
| means "or"
{ }* means zero or more times;
<void> means no characters at all
]]>
Notes
- Comments in RPCL start with two dashes '--' and end at the end of
the line. Comments can be put anywhere except inside keywords or identifiers.
- STRING is not equivalent to a type SEQUENCE OF RPC_CHAR, because a
special (more efficient) Courier message format is used to represent
objects of type STRING and SUBSTRING.
- The maximum length of identifier is limited to 25 characters.
- RPCL is case independent, meaning that you can write your desciption
file in any mixture of upper and lower case. The identifiers 'VAR_ONE'
and 'var_one' are, for example, the same, as are the keywords "String"
and "STRING".
- Identifiers may not be reserved words in any language in which stubs
are to be generated. In order to avoid clashes within the stubs, one
should also avoid identifiers starting with any of:
<![CDATA[
abort_ call_ m_ reject_ return_ rpc_
]]>
- Similarly, one should avoid the identifiers:
<![CDATA[
b header procedure_number
program_number version_number which
why
]]>
- The package should not have the same name as any of the procedures
within it.