gram.head

unix v7是最后一个广泛发布的研究型UNIX版本

%{
#include "defs"

static int nstars;
static int ndim;
static int vartype;
static ftnint varleng;
static struct { ptr lb, ub; } dims[8];
static struct labelblock *labarray[MAXLABLIST];
static int lastwasbranch = NO;
static int thiswasbranch = NO;
extern ftnint yystno;

ftnint convci();
double convcd();
struct addrblock *nextdata(), *mkbitcon();
struct constblock *mklogcon(), *mkaddcon(), *mkrealcon();
struct constblock *mkstrcon(), *mkcxcon();
struct listblock *mklist();
struct listblock *mklist();
struct impldoblock *mkiodo();
struct extsym *comblock();

%}

/* Specify precedences and associativies. */

%left SCOMMA
%nonassoc SCOLON
%right SEQUALS
%left SEQV SNEQV
%left SOR
%left SAND
%left SNOT
%nonassoc SLT SGT SLE SGE SEQ SNE
%left SCONCAT
%left SPLUS SMINUS
%left SSTAR SSLASH
%right SPOWER

%%

program:
	| program stat SEOS
	;

stat:	  thislabel entry
		{ lastwasbranch = NO; }
	| thislabel  spec
	| thislabel  exec
		{ if($1 && ($1->labelno==dorange))
			enddo($1->labelno);
		  if(lastwasbranch && thislabel==NULL)
			warn1("statement cannot be reached");
		  lastwasbranch = thiswasbranch;
		  thiswasbranch = NO;
		}
	| thislabel SINCLUDE filename
		{ doinclude( $3 ); }
	| thislabel  SEND  end_spec
		{ lastwasbranch = NO;  endproc(); }
	| thislabel SUNKNOWN
		{ execerr("unclassifiable statement", 0);  flline(); };
	| error
		{ flline();  needkwd = NO;  inioctl = NO; 
		  yyerrok; yyclearin; }
	;

thislabel:  SLABEL
		{
		if(yystno != 0)
			{
			$$ = thislabel =  mklabel(yystno);
			if( ! headerdone )
				puthead(NULL, procclass);
			if(thislabel->labdefined)
				execerr("label %s already defined",
					convic(thislabel->stateno) );
			else	{
				if(thislabel->blklevel!=0 && thislabel->blklevel<blklevel
				    && thislabel->labtype!=LABFORMAT)
					warn1("there is a branch to label %s from outside block",
					      convic( (ftnint) (thislabel->stateno) ) );
				thislabel->blklevel = blklevel;
				thislabel->labdefined = YES;
				if(thislabel->labtype != LABFORMAT)
					putlabel(thislabel->labelno);
				}
			}
		else    $$ = thislabel = NULL;
		}
	;

entry:	  SPROGRAM new_proc progname
		{ startproc($3, CLMAIN); }
	| SBLOCK new_proc progname
		{ startproc($3, CLBLOCK); }
	| SSUBROUTINE new_proc entryname arglist
		{ entrypt(CLPROC, TYSUBR, (ftnint) 0,  $3, $4); }
	| SFUNCTION new_proc entryname arglist
		{ entrypt(CLPROC, TYUNKNOWN, (ftnint) 0, $3, $4); }
	| type SFUNCTION new_proc entryname arglist
		{ entrypt(CLPROC, $1, varleng, $4, $5); }
	| SENTRY entryname arglist
		{ if(parstate==OUTSIDE || procclass==CLMAIN
			|| procclass==CLBLOCK)
				execerr("misplaced entry statement", 0);
		  entrypt(CLENTRY, 0, (ftnint) 0, $2, $3);
		}
	;

new_proc:
		{ newproc(); }
	;

entryname:  name
		{ $$ = newentry($1); }
	;

name:	  SNAME
		{ $$ = mkname(toklen, token); }
	;

progname:		{ $$ = NULL; }
	| entryname
	;

arglist:
		{ $$ = 0; }
	| SLPAR SRPAR
		{ $$ = 0; }
	| SLPAR args SRPAR
		{$$ = $2; }
	;

args:	  arg
		{ $$ = ($1 ? mkchain($1,0) : 0 ); }
	| args SCOMMA arg
		{ if($3) $1 = $$ = hookup($1, mkchain($3,0)); }
	;

arg:	  name
		{ $1->vstg = STGARG; }
	| SSTAR
		{ $$ = 0;  substars = YES; }
	;



filename:   SHOLLERITH
		{
		char *s;
		s = copyn(toklen+1, token);
		s[toklen] = '\0';
		$$ = s;
		}
	;