ack/lang/m2/comp/program.g
1986-04-28 18:06:58 +00:00

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/* O V E R A L L S T R U C T U R E */
{
static char *RcsId = "$Header$";
#include <alloc.h>
#include <em_arith.h>
#include <em_label.h>
#include "main.h"
#include "idf.h"
#include "LLlex.h"
#include "scope.h"
#include "def.h"
#include "type.h"
#include "node.h"
#include "debug.h"
static int DEFofIMPL = 0; /* Flag indicating that we are currently
parsing the definition module of the
implementation module currently being
compiled
*/
struct def *currentdef; /* current definition of module or procedure */
}
/*
The grammar as given by Wirth is already almost LL(1); the
main problem is that the full form of a qualified designator
may be:
[ module_ident '.' ]* IDENT [ '.' field_ident ]*
which is quite confusing to an LL(1) parser. Rather than
resorting to context-sensitive techniques, I have decided
to render this as:
IDENT [ '.' IDENT ]*
on the grounds that it is quite natural to consider the first
IDENT to be the name of the object and regard the others as
field identifiers.
*/
%lexical LLlex;
%start CompUnit, CompilationUnit;
%start DefModule, DefinitionModule;
ModuleDeclaration
{
struct idf *id;
register struct def *df;
struct def *savecurr = currentdef;
extern int proclevel;
static int modulecount = 0;
char buf[256];
struct node *nd;
struct node *exportlist = 0;
int qualified;
extern char *sprint(), *Malloc(), *strcpy();
} :
MODULE IDENT {
id = dot.TOK_IDF;
df = define(id, CurrentScope, D_MODULE);
currentdef = df;
if (!df->mod_vis) {
open_scope(CLOSEDSCOPE);
df->mod_vis = CurrVis;
}
else CurrVis = df->mod_vis;
df->df_type = standard_type(T_RECORD, 0, (arith) 0);
df->df_type->rec_scope = df->mod_vis->sc_scope;
df->mod_number = ++modulecount;
sprint(buf, "__%d%s", df->mod_number, id->id_text);
CurrentScope->sc_name =
Malloc((unsigned) (strlen(buf) + 1));
strcpy(CurrentScope->sc_name, buf);
C_ina_dnam(&buf[1]);
C_inp(buf);
}
priority(&(df->mod_priority))?
';'
import(1)*
export(&qualified, &exportlist, 0)?
block(&nd)
IDENT { InitProc(nd, df);
if (exportlist) {
Export(exportlist, qualified, df);
FreeNode(exportlist);
}
close_scope(SC_CHKFORW|SC_CHKPROC|SC_REVERSE);
match_id(id, dot.TOK_IDF);
currentdef = savecurr;
}
;
priority(arith *pprio;)
{
struct node *nd;
} :
'[' ConstExpression(&nd) ']'
{ if (!(nd->nd_type->tp_fund & T_INTORCARD)) {
node_error(nd, "Illegal priority");
}
*pprio = nd->nd_INT;
FreeNode(nd);
}
;
export(int *QUALflag; struct node **ExportList; int def;)
{
} :
EXPORT
[
QUALIFIED
{ *QUALflag = 1; }
|
{ *QUALflag = 0; }
]
IdentList(ExportList) ';'
{
if (def) {
node_warning(*ExportList, "export list in definition module ignored");
FreeNode(*ExportList);
}
}
;
import(int local;)
{
struct node *ImportList;
struct node *id = 0;
} :
[ FROM
IDENT { id = MkNode(Value, NULLNODE, NULLNODE, &dot); }
]?
IMPORT IdentList(&ImportList) ';'
/*
When parsing a global module, this is the place where we must
read already compiled definition modules.
If the FROM clause is present, the identifier in it is a module
name, otherwise the names in the import list are module names.
*/
{
Import(ImportList, id, local);
}
;
DefinitionModule
{
register struct def *df;
struct idf *id;
struct node *exportlist;
int dummy;
} :
DEFINITION
MODULE IDENT {
id = dot.TOK_IDF;
df = define(id, GlobalScope, D_MODULE);
if (!SYSTEMModule) open_scope(CLOSEDSCOPE);
if (!Defined) Defined = df;
df->mod_vis = CurrVis;
df->mod_number = 0;
CurrentScope->sc_name = id->id_text;
df->df_type = standard_type(T_RECORD, 0, (arith) 0);
df->df_type->rec_scope = df->mod_vis->sc_scope;
DefinitionModule++;
DO_DEBUG(1, debug("Definition module \"%s\" %d",
id->id_text, DefinitionModule));
}
';'
import(0)*
export(&dummy, &exportlist, 1)?
/* New Modula-2 does not have export lists in definition modules.
For the time being, we ignore export lists here, and a
warning is issued.
*/
definition* END IDENT
{
if (DEFofIMPL) {
/* Just read the definition module of the
implementation module being compiled
*/
RemImports(&(CurrentScope->sc_def));
}
df = CurrentScope->sc_def;
while (df) {
/* Make all definitions "QUALIFIED EXPORT" */
df->df_flags |= D_QEXPORTED;
df = df->df_nextinscope;
}
if (!SYSTEMModule) close_scope(SC_CHKFORW);
DefinitionModule--;
match_id(id, dot.TOK_IDF);
}
'.'
;
definition
{
struct def *df;
} :
CONST [ ConstantDeclaration Semicolon ]*
|
TYPE
[ IDENT { df = define(dot.TOK_IDF, CurrentScope, D_TYPE); }
[ '=' type(&(df->df_type))
| /* empty */
/*
Here, the exported type has a hidden implementation.
The export is said to be opaque.
It is restricted to pointer types.
*/
{ df->df_kind = D_HIDDEN;
df->df_type = construct_type(T_POINTER, NULLTYPE);
}
]
Semicolon
]*
|
VAR [ VariableDeclaration Semicolon ]*
|
ProcedureHeading(&df, D_PROCHEAD) Semicolon
;
Semicolon:
';'
|
{ warning("; expected"); }
;
ProgramModule(int state;)
{
struct idf *id;
struct def *GetDefinitionModule();
register struct def *df;
struct node *nd;
} :
MODULE
IDENT {
id = dot.TOK_IDF;
if (state == IMPLEMENTATION) {
DEFofIMPL = 1;
df = GetDefinitionModule(id);
currentdef = df;
CurrVis = df->mod_vis;
CurrentScope = CurrVis->sc_scope;
DEFofIMPL = 0;
}
else {
df = define(id, CurrentScope, D_MODULE);
Defined = df;
open_scope(CLOSEDSCOPE);
df->mod_vis = CurrVis;
df->mod_number = 0;
CurrentScope->sc_name = id->id_text;
}
}
priority(&(df->mod_priority))?
';' import(0)*
block(&nd) IDENT
{ InitProc(nd, df);
close_scope(SC_CHKFORW|SC_CHKPROC|SC_REVERSE);
match_id(id, dot.TOK_IDF);
}
'.'
;
Module
{
int state = PROGRAM;
} :
DefinitionModule
|
[
IMPLEMENTATION { state = IMPLEMENTATION; }
]?
ProgramModule(state)
;
CompilationUnit:
Module
;