118 lines
2.2 KiB
Text
118 lines
2.2 KiB
Text
/* O V E R A L L S T R U C T U R E */
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{
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static char *RcsId = "$Header$";
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#include <alloc.h>
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#include <em_arith.h>
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#include "idf.h"
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#include "misc.h"
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#include "main.h"
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#include "LLlex.h"
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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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%lexical LLlex;
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%start CompUnit, CompilationUnit;
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ModuleDeclaration:
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MODULE IDENT priority? ';' import(1)* 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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FreeIdList(ExportList);
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}
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;
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import(int local;)
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{
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struct id_list *ImportList;
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struct idf *id = 0;
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} :
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[ FROM
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IDENT { id = dot.TOK_IDF; }
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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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FreeIdList(ImportList);
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}
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;
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DefinitionModule:
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DEFINITION { state = DEFINITION; }
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MODULE IDENT
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';'
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import(0)*
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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 { if (state != IMPLEMENTATION) state = PROGRAM; }
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IDENT priority? ';' import(0)* block IDENT '.'
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;
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Module:
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DefinitionModule
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[
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IMPLEMENTATION { state = IMPLEMENTATION; }
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]?
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ProgramModule
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;
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CompilationUnit:
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Module
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;
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