gram.head

<B>Digital的Unix操作系统VAX 4.2源码</B>

%{
#include "defs"
ptr bgnexec(), addexec(), bgnproc(), mkvar(), mkcomm(), mkstruct(), mkarrow();
ptr mkiost(), mkioitem(), mkiogroup(), mkformat();
ptr funcinv(), extrfield(), typexpr(), strucelt(), mkfield();
ptr esizeof(), elenof(), mkilab();
ptr ifthen(), doloop();
struct varblock *subscript();
%}

%start graal
%union { int ival; ptr pval; char *cval; }

%left COLON
%left COMMA
%right ASGNOP	/* = +- -= ...  */
%right REPOP	/*  $  */
%left OR	/*  |  ||  */
%left AND	/*  &  &&  */
%left NOT
%nonassoc RELOP	/*  LT GT LE GE EQ NE  */
%left ADDOP	/* +  -  */
%left MULTOP	/* *  /  */
%right POWER	/*   **  ^  */
%left ARROW QUALOP	/*  ->  .  */

%type <pval> dcl stat exec stats proc args arg varname comname structname
%type <pval> dcl1 dcls1 dcl dcls specs equivlist attrs attr comclass
%type <pval> dim dimbound bounds bound ubound vars varlist var
%type <pval> specarray spec deftype struct
%type <pval> expr lhs parexprs iostat sizeof lengthof lhs1 lhsname exprlist
%type <pval> beginexec control until lablist parlablist compgotoindex
%type <pval> do exprnull fortest iostat iounit iolist ioitem iobrace
%type <pval> format
%type <ival> stype sclass prec logcon logval brk blocktype letter iokwd label
%token <pval> CONST OPTNAME COMNAME STRUCTNAME NAME ESCAPE
%token <ival> RELOP ASGNOP OR AND NOT ADDOP MULTOP POWER DOUBLEADDOP
%token <ival> LETTER TRUE FALSE

%{
extern int prevv;
extern YYSTYPE prevl;
ptr p;
ptr procattrs;
int i,n;
static int imptype;
static int ininit =NO;

%}

%%


graal:
		{ graal = PARSEOF; }
	| option endchunk
		{ graal = PARSOPT; }
	| dcl endchunk
		{ graal = PARSDCL; doinits($1);  frchain( & $1); }
	| procst EOS stats end
		{ endproc(); graal = PARSPROC; }
	| define endchunk
		{ graal = PARSDEF; }
	| exec endchunk
		{ graal = PARSERR; }
	| error
		{ graal = PARSERR;
		  errmess("Syntax error", "", "");
		}
	;

endchunk:  EOS	{ eofneed = 1; }

stat:	  dcl EOS
		{ if(!dclsect)
			warn("declaration amid executables");
		    $$ = bgnexec();
		   TEST fprintf(diagfile,"stat: dcl\n");
		  doinits($1); frchain( & $1); }
	| exec EOS 
		{ if(dclsect && $1->tag!=TSTFUNCT)
			dclsect = 0;
		    TEST fprintf(diagfile, "stat: exec\n"); }
	| define EOS
		{ $$ = bgnexec(); }
	| error EOS
		{ yyerrok;
		  errmess("Syntax error", "", "");
		  $$ = bgnexec();
		}
	;

stats:
		{ $$ = bgnexec(); }
	| stats   { thisexec->copylab = 1; }   stat
		{ $$ = addexec(); thisexec->copylab = 0; }
	;

procst:	  oproc
		{ procname = 0; thisargs = 0;
		  if(procclass == 0) procclass = PRMAIN;
		  goto proctype;
		}
	| oproc procname
		{ thisargs = 0; goto proctype; }
	| oproc procname LPAR RPAR
		{ thisargs = 0; goto proctype; }
	| oproc procname LPAR args RPAR
		{ thisargs = $4;
	proctype:
		if(procattrs)
			if(procname == 0)
				dclerr("attributes on unnamed procedure", "");
			else	{
				attvars(procattrs, mkchain(procname,CHNULL));
				procclass = PRFUNCT;
				}
		fprintf(diagfile, "Procedure %s:\n", procnm() );
		if(verbose)
			fprintf(diagfile, "    Pass 1\n");
		}
	;

procname:  NAME
		{ procname = mkvar($1);
		  extname(procname);
		}
	;

oproc:	  proc
		{ procattrs = 0; }
	| attrs proc
		{ procattrs = $1;
		  if(procclass == 0) procclass = PRFUNCT;
		}
	;

proc:	  PROCEDURE
		{ $$ = bgnproc(); procclass = 0; }
	| BLOCKDATA
		{ $$ = bgnproc(); procclass = PRBLOCK; }
	;

args:	  arg
		{ $$ = mkchain($1,CHNULL); }
	| args COMMA arg
		{ hookup($1, mkchain($3,CHNULL) ); }
	;

arg:	  varname
		{ if($1->vclass == CLUNDEFINED)
			$1->vclass = CLARG;
		  else dclerr("argument already used", $1->sthead->namep);
		}
	;

option:	  optson optionnames   { optneed = 0; }
	;

optson:	  OPTION
		{ if(blklevel > 0)
			{
			execerr("Option statement inside procedure", "");
			execerr("procedure %s terminated prematurely", procnm());
			endproc();
			}
		  optneed = 1;
		  }
	;

optionnames:
	| optionnames optelt
	| optionnames optelt COMMA
	;

optelt:	  OPTNAME
		{ setopt($1,CNULL); cfree($1); }
	| OPTNAME ASGNOP OPTNAME
		{ setopt($1,$3); cfree($1); cfree($3); }
	| OPTNAME ASGNOP CONST
		{ setopt($1,$3->leftp); cfree($1); cfree($3); }
	;


define:	  DEFINE   { defneed = 1; }
	;

end:	  END
		{ if(thisctl->subtype != STPROC)
			execerr("control stack not empty upon END", "");
		  exnull();
		  popctl();
		}
	;

contnu:
		{ igeol=1; /* continue past newlines  */ }
	;