117 lines
2 KiB
Text
117 lines
2 KiB
Text
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/*
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Program: Modula-2 grammar in LL(1) form
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Version: Mon Feb 24 14:29:39 MET 1986
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*/
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/*
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The grammar as given by Wirth is already almost LL(1); the
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main problem is that the full form of a qualified designator
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may be:
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[ module_ident '.' ]* IDENT [ '.' field_ident ]*
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which is quite confusing to an LL(1) parser. Rather than
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resorting to context-sensitive techniques, I have decided
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to render this as:
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IDENT [ '.' IDENT ]*
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on the grounds that it is quite natural to consider the first
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IDENT to be the name of the object and regard the others as
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field identifiers.
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*/
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{
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#include "idf.h"
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#include "idlist.h"
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static char *RcsId = "$Header$";
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}
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%lexical LLlex;
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%start CompUnit, CompilationUnit;
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ModuleDeclaration:
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MODULE IDENT priority? ';' import* export? block IDENT
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;
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priority:
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'[' ConstExpression ']'
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;
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export
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{
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struct id_list *ExportList;
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} :
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EXPORT QUALIFIED? IdentList(&ExportList) ';'
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;
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import
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{
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struct id_list *ImportList;
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} :
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[ FROM
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IDENT
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]?
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IMPORT IdentList(&ImportList) ';'
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/*
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When parsing a global module, this is the place where we must
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read already compiled definition modules.
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If the FROM clause is present, the identifier in it is a module
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name, otherwise the names in the import list are module names.
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*/
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;
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DefinitionModule:
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DEFINITION
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{
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#ifdef DEBUG
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debug("Definition module");
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#endif DEBUG
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}
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MODULE IDENT ';' import*
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/* export?
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New Modula-2 does not have export lists in definition modules.
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*/
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definition* END IDENT '.'
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;
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definition:
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CONST [ ConstantDeclaration ';' ]*
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TYPE
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[ IDENT
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[ '=' type
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| /* empty */
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/*
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Here, the exported type has a hidden implementation.
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The export is said to be opaque.
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It is restricted to pointer types.
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*/
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]
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';'
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]*
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VAR [ VariableDeclaration ';' ]*
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ProcedureHeading ';'
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;
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ProgramModule:
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MODULE
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{
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#ifdef DEBUG
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debug("Program module");
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#endif DEBUG
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}
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IDENT priority? ';' import* block IDENT '.'
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;
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Module:
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DefinitionModule
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IMPLEMENTATION? ProgramModule
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;
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CompilationUnit:
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Module
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;
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