scan.c

unix v7是最后一个广泛发布的研究型UNIX版本

# include "mfile1"
# include <ctype.h>
	/* temporarily */

	/* lexical actions */

# define A_ERR 0		/* illegal character */
# define A_LET 1		/* saw a letter */
# define A_DIG 2		/* saw a digit */
# define A_1C 3			/* return a single character */
# define A_STR 4		/* string */
# define A_CC 5			/* character constant */
# define A_BCD 6		/* GCOS BCD constant */
# define A_SL 7			/* saw a / */
# define A_DOT 8		/* saw a . */
# define A_PL 9		/* + */
# define A_MI 10		/* - */
# define A_EQ 11		/* = */
# define A_NOT 12		/* ! */
# define A_LT 13		/* < */
# define A_GT 14		/* > */
# define A_AND 16		/* & */
# define A_OR 17		/* | */
# define A_WS 18		/* whitespace (not \n) */
# define A_NL 19		/* \n */

	/* character classes */

# define LEXLET 01
# define LEXDIG 02
# define LEXOCT 04
# define LEXHEX 010
# define LEXWS 020
# define LEXDOT 040

	/* reserved word actions */

# define AR_TY 0		/* type word */
# define AR_RW 1		/* simple reserved word */
# define AR_CL 2		/* storage class word */
# define AR_S 3		/* struct */
# define AR_U 4		/* union */
# define AR_E 5		/* enum */
# define AR_A 6		/* asm */

	/* text buffer */
# define LXTSZ 100
char yytext[LXTSZ];
char * lxgcp;


	/* ARGSUSED */
mainp1( argc, argv ) int argc; char *argv[]; {  /* control multiple files */

	register i;
	register char *cp;
	extern int idebug, bdebug, tdebug, edebug, ddebug, xdebug;

	for( i=1; i<argc; ++i ){
		if( *(cp=argv[i]) == '-' && *++cp == 'X' ){
			while( *++cp ){
				switch( *cp ){

				case 'd':
					++ddebug;
					break;
				case 'i':
					++idebug;
					break;
				case 'b':
					++bdebug;
					break;
				case 't':
					++tdebug;
					break;
				case 'e':
					++edebug;
					break;
				case 'x':
					++xdebug;
					break;
					}
				}
			}
		}

# ifdef ONEPASS
	p2init( argc, argv );
# endif

	for( i=0; i<SYMTSZ; ++i ) stab[i].stype = TNULL;

	lxinit();
	tinit();
	mkdope();

	lineno = 1;

	/* dimension table initialization */

	dimtab[NULL] = 0;
	dimtab[CHAR] = SZCHAR;
	dimtab[INT] = SZINT;
	dimtab[FLOAT] = SZFLOAT;
	dimtab[DOUBLE] = SZDOUBLE;
	dimtab[LONG] = SZLONG;
	dimtab[SHORT] = SZSHORT;
	dimtab[UCHAR] = SZCHAR;
	dimtab[USHORT] = SZSHORT;
	dimtab[UNSIGNED] = SZINT;
	dimtab[ULONG] = SZLONG;
	/* starts past any of the above */
	curdim = 16;
	reached = 1;

	yyparse();
	yyaccpt();

	ejobcode( nerrors ? 1 : 0 );
	return(nerrors?1:0);

	}

# ifdef ibm

# define CSMASK 0377
# define CSSZ 256

# else

# define CSMASK 0177
# define CSSZ 128

# endif

short lxmask[CSSZ+1];

lxenter( s, m ) register char *s; register short m; {
	/* enter a mask into lxmask */
	register c;

	while( c= *s++ ) lxmask[c+1] |= m;

	}


# define lxget(c,m) (lxgcp=yytext,lxmore(c,m))

lxmore( c, m )  register c, m; {
	register char *cp;

	*(cp = lxgcp) = c;
	while( c=getchar(), lxmask[c+1]&m ){
		if( cp < &yytext[LXTSZ-1] ){
			*++cp = c;
			}
		}
	ungetc(c,stdin);
	*(lxgcp = cp+1) = '\0';
	}

struct lxdope {
	short lxch;	/* the character */
	short lxact;	/* the action to be performed */
	short lxtok;	/* the token number to be returned */
	short lxval;	/* the value to be returned */
	} lxdope[] = {

	'$',	A_ERR,	0,	0,	/* illegal characters go here... */
	'_',	A_LET,	0,	0,	/* letters point here */
	'0',	A_DIG,	0,	0,	/* digits point here */
	' ',	A_WS,	0,	0,	/* whitespace goes here */
	'\n',	A_NL,	0,	0,
	'"',	A_STR,	0,	0,	/* character string */
	'\'',	A_CC,	0,	0,	/* character constant */
	'`',	A_BCD,	0,	0,	/* GCOS BCD constant */
	'(',	A_1C,	LP,	0,
	')',	A_1C,	RP,	0,
	'{',	A_1C,	LC,	0,
	'}',	A_1C,	RC,	0,
	'[',	A_1C,	LB,	0,
	']',	A_1C,	RB,	0,
	'*',	A_1C,	MUL,	MUL,
	'?',	A_1C,	QUEST,	0,
	':',	A_1C,	COLON,	0,
	'+',	A_PL,	PLUS,	PLUS,
	'-',	A_MI,	MINUS,	MINUS,
	'/',	A_SL,	DIVOP,	DIV,
	'%',	A_1C,	DIVOP,	MOD,
	'&',	A_AND,	AND,	AND,
	'|',	A_OR,	OR,	OR,
	'^',	A_1C,	ER,	ER,
	'!',	A_NOT,	UNOP,	NOT,
	'~',	A_1C,	UNOP,	COMPL,
	',',	A_1C,	CM,	CM,
	';',	A_1C,	SM,	0,
	'.',	A_DOT,	STROP,	DOT,
	'<',	A_LT,	RELOP,	LT,
	'>',	A_GT,	RELOP,	GT,
	'=',	A_EQ,	ASSIGN,	ASSIGN,
	-1,	A_1C,	0,	0,
	};

struct lxdope *lxcp[CSSZ+1];

lxinit(){
	register struct lxdope *p;
	register i;
	register char *cp;
	/* set up character classes */

	lxenter( "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_", LEXLET );
	lxenter( "0123456789", LEXDIG );
	lxenter( "0123456789abcdefABCDEF", LEXHEX );
	lxenter( " \t\r\b\f", LEXWS );
	lxenter( "01234567", LEXOCT );
	lxmask['.'+1] |= LEXDOT;

	/* make lxcp point to appropriate lxdope entry for each character */

	/* initialize error entries */

	for( i= 0; i<=CSSZ; ++i ) lxcp[i] = lxdope;

	/* make unique entries */

	for( p=lxdope; ; ++p ) {
		lxcp[p->lxch+1] = p;
		if( p->lxch < 0 ) break;
		}

	/* handle letters, digits, and whitespace */
	/* by convention, first, second, and third places */

	cp = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	while( *cp ) lxcp[*cp++ + 1] = &lxdope[1];
	cp = "123456789";
	while( *cp ) lxcp[*cp++ + 1] = &lxdope[2];
	cp = "\t\b\r\f";
	while( *cp ) lxcp[*cp++ + 1] = &lxdope[3];

	/* first line might have title */
	lxtitle();

	}

int lxmatch;  /* character to be matched in char or string constant */

lxstr(ct){
	/* match a string or character constant, up to lxmatch */

	register c;
	register val;
	register i;

	i=0;
	while( (c=getchar()) != lxmatch ){
		switch( c ) {

		case EOF:
			uerror( "unexpected EOF" );
			break;

		case '\n':
			uerror( "newline in string or char constant" );
			++lineno;
			break;

		case '\\':
			switch( c = getchar() ){

			case '\n':
				++lineno;
				continue;

			default:
				val = c;
				goto mkcc;

			case 'n':
				val = '\n';
				goto mkcc;

			case 'r':
				val = '\r';
				goto mkcc;

			case 'b':
				val = '\b';
				goto mkcc;

			case 't':
				val = '\t';
				goto mkcc;

			case 'f':
				val = '\f';
				goto mkcc;

			case '0':
			case '1':
			case '2':
			case '3':
			case '4':
			case '5':
			case '6':
			case '7':
				val = c-'0';
				c=getchar();  /* try for 2 */
				if( lxmask[c+1] & LEXOCT ){
					val = (val<<3) | (c-'0');
					c = getchar();  /* try for 3 */
					if( lxmask[c+1] & LEXOCT ){
						val = (val<<3) | (c-'0');
						}
					else ungetc( c ,stdin);
					}
				else ungetc( c ,stdin);

				goto mkcc1;

				}
		default:
			val =c;
		mkcc:
			val = CCTRANS(val);
		mkcc1:
			if( lxmatch == '\'' ){
				val = CHARCAST(val);  /* it is, after all, a "character" constant */
				makecc( val, i );
				}
			else { /* stash the byte into the string */
				if( strflg ) {
					if( ct==0 || i<ct ) putbyte( val );
					else if( i == ct ) werror( "non-null byte ignored in string initializer" );
					}
				else bycode( val, i );
				}
			++i;
			continue;
			}
		break;
		}
	/* end of string or  char constant */

	if( lxmatch == '"' ){
		if( strflg ){ /* end the string */
			if( ct==0 || i<ct ) putbyte( 0 );  /* the null at the end */
			}
		else {  /* the initializer gets a null byte */
			bycode( 0, i++ );
			bycode( -1, i );
			dimtab[curdim] = i;  /* in case of later sizeof ... */
			}
		}
	else { /* end the character constant */
		if( i == 0 ) uerror( "empty character constant" );
		if( i>(SZINT/SZCHAR) || ( (pflag||hflag)&&i>1) )
			uerror( "too many characters in character constant" );
		}
	}

lxcom(){
	register c;
	/* saw a /*: process a comment */

	for(;;){

		switch( c = getchar() ){

		case EOF:
			uerror( "unexpected EOF" );
			return;

		case '\n':
			++lineno;

		default:
			continue;

		case '*':
			if( (c = getchar()) == '/' ) return;
			else ungetc( c ,stdin);
			continue;

# ifdef LINT
		case 'V':
			lxget( c, LEXLET|LEXDIG );
			{
				extern int vaflag;
				int i;
				i = yytext[7]?yytext[7]-'0':0;
				yytext[7] = '\0';
				if( strcmp( yytext, "VARARGS" ) ) continue;
				vaflag = i;
				continue;
				}
		case 'L':
			lxget( c, LEXLET );
			if( strcmp( yytext, "LINTLIBRARY" ) ) continue;
			{
				extern int libflag;
				libflag = 1;
				}
			continue;

		case 'A':
			lxget( c, LEXLET );
			if( strcmp( yytext, "ARGSUSED" ) ) continue;
			{
				extern int argflag, vflag;
				argflag = 1;
				vflag = 0;
				}
			continue;

		case 'N':
			lxget( c, LEXLET );
			if( strcmp( yytext, "NOTREACHED" ) ) continue;
			reached = 0;
			continue;
# endif
			}
		}
	}

yylex(){
	for(;;){

		register lxchar;
		register struct lxdope *p;
		register struct symtab *sp;
		int id;

		switch( (p=lxcp[(lxchar=getchar())+1])->lxact ){

		onechar:
			ungetc( lxchar ,stdin);

		case A_1C:
			/* eat up a single character, and return an opcode */

			yylval.intval = p->lxval;
			return( p->lxtok );

		case A_ERR:
			uerror( "illegal character: %03o (octal)", lxchar );
			break;

		case A_LET:
			/* collect an identifier, check for reserved word, and return */
			lxget( lxchar, LEXLET|LEXDIG );
			if( (lxchar=lxres()) > 0 ) return( lxchar ); /* reserved word */
			if( lxchar== 0 ) continue;
			id = lookup( yytext, (stwart&(INSTRUCT|INUNION|FUNNYNAME))?SMOS:0 );
			sp = &stab[id];
			if( sp->sclass == TYPEDEF && !stwart ){
				stwart = instruct;
				yylval.nodep = mkty( sp->stype, sp->dimoff, sp->sizoff );
				return( TYPE );
				}
			stwart = (stwart&SEENAME) ? instruct : 0;
			yylval.intval = id;
			return( NAME );

		case A_DIG:
			/* collect a digit string, then look at last one... */
			lastcon = 0;
			lxget( lxchar, LEXDIG );