prompts revisited

[unix-history] / usr / src / usr.bin / pascal / pdx / command / token.l

%{
/* Copyright (c) 1982 Regents of the University of California */

static char sccsid[] = "@(#)token.l 1.3 %G%";

/*
 * Token definitions for pdx scanner.
 */

#include "defs.h"
#include "command.h"
#include "y.tab.h"
#include "main.h"
#include "symtab.h"
#include "sym.h"
#include "process.h"
#include "process/pxinfo.h"

char *initfile = ".pdxinit";

/*
 * This is a silly "lex" thing.
 */

#define yywrap()	(1)

/*
 * Override Lex default input macros.
 */

#undef  input
#undef  unput

#define unput(c)	ungetc(c, yyin)

%}

blank		[ \t]
white		{blank}+
alpha		[a-zA-Z]
digit		[0-9]
n		{digit}+
h		[0-9a-fA-F]+
e		(("e"|"E")("+"|"-")?{n})
alphanum	[a-zA-Z0-9]
ident		{alpha}{alphanum}*
filenm		[^ \t\n"<>!*"]+
qfilenm		{filenm}/":"
string		'[^']+'('[^']*')*
newline		"\n"
char		.

%Start file sh

%%

{white}		;
^sh{white}.*$	{ BEGIN 0; yylval.y_string = &yytext[3]; return(SH); }
^sh		{ BEGIN 0; yylval.y_string = NIL; return(SH); }
^{ident}	{ return(findcmd(yytext)); }
<file>{filenm}	{ yylval.y_string = strdup(yytext); return(FILENAME); }
{qfilenm}	{ yylval.y_string = strdup(yytext); return(FILENAME); }
{n}?\.{n}{e}?	{ yylval.y_real = atof(yytext); return(REAL); }
0{n}		{ yylval.y_long = octal(yytext); return(INT); }
0x{h}		{ yylval.y_long = hex(yytext); return(INT); }
{n}		{ yylval.y_long = atol(yytext); return(INT); }
at		{ return(AT); }
{ident}		{ return(ident(yytext)); }
{string}	{ yylval.y_string = yytext; return(STRING); }
"%dp"		{ yylval.y_long = (long) DP; return(INT); }
{newline}	{ BEGIN 0; nlflag = TRUE; return('\n'); }
{char}		{ return(yylval.y_int = yytext[0]); }

%%

LOCAL SYMTAB *dbtab, *specialtab;

/*
 * Look for the given string in the debugger keyword table.
 * If it's there, return the associated token, otherwise report an error.
 */

LOCAL int findcmd(s)
char *s;
{
	register SYM *p;

	if ((p = st_lookup(dbtab, s)) == NIL) {
		error("\"%s\" is not a command", s);
	}
	yylval.y_int = tokval(p);
	switch (toknum(p)) {
		case ALIAS:
		case DUMP:
		case EDIT:
		case CHFILE:
		case RUN:
		case SOURCE:
		case STATUS:
			BEGIN file;
			break;

		default:
			/* do nothing */;
	}
	return(toknum(p));
}

/*
 * Look for a symbol, first in the special table (if, in, etc.)
 * then in the symbol table.  If it's there, return the SYM pointer,
 * otherwise it's an error.
 */

LOCAL int ident(s)
char *s;
{
	register SYM *p;

	if ((p = st_lookup(specialtab, s)) != NIL) {
		yylval.y_sym = p;
		return(toknum(p));
	}
	p = st_lookup(symtab, s);
	if (p == NIL) {
		if (strcmp(s, "nil") == 0) {
			yylval.y_long = 0L;
			return(INT);
		} else {
			error("\"%s\" is not defined", s);
		}
	}
	yylval.y_sym = p;
	return(NAME);
}

/*
 * Convert a string to octal.  No check that digits are less than 8.
 */

LOCAL int octal(s)
char *s;
{
	register char *p;
	register int n;

	n = 0;
	for (p = s; *p != '\0'; p++) {
		n = 8*n + (*p - '0');
	}
	return(n);
}

/*
 * Convert a string to hex.
 */

LOCAL int hex(s)
char *s;
{
	register char *p;
	register int n;

	n = 0;
	for (p = s+2; *p != '\0'; p++) {
		n *= 16;
		if (*p >= 'a' && *p <= 'f') {
			n += (*p - 'a' + 10);
		} else if (*p >= 'A' && *p <= 'F') {
			n += (*p - 'A' + 10);
		} else {
			n += (*p - '0');
		}
	}
	return(n);
}

/*
 * Initialize the debugger keyword table (dbtab) and special symbol
 * table (specialtab).
 */

#define db_keyword(nm, n)	make_keyword(dbtab, nm, n)
#define sp_keyword(nm, n)	make_keyword(specialtab, nm, n)

lexinit()
{
	dbtab = st_creat(150);
	db_keyword("alias", ALIAS);
	db_keyword("assign", ASSIGN);
	db_keyword("call", CALL);
	db_keyword("cont", CONT);
	db_keyword("delete", DELETE);
	db_keyword("dump", DUMP);
	db_keyword("edit", EDIT);
	db_keyword("file", CHFILE);
	db_keyword("gripe", GRIPE);
	db_keyword("help", HELP);
	db_keyword("list", LIST);
	db_keyword("next", NEXT);
	db_keyword("pi", REMAKE);
	db_keyword("print", PRINT);
	db_keyword("quit", QUIT);
	db_keyword("run", RUN);
	db_keyword("sh", SH);
	db_keyword("source", SOURCE);
	db_keyword("status", STATUS);
	db_keyword("step", STEP);
	db_keyword("stop", STOP);
	db_keyword("stopi", STOPI);
	db_keyword("trace", TRACE);
	db_keyword("tracei", TRACEI);
	db_keyword("whatis", WHATIS);
	db_keyword("where", WHERE);
	db_keyword("which", WHICH);
	db_keyword("xd", XD);
	db_keyword("xi", XI);

	specialtab = st_creat(10);
	sp_keyword("div", DIV);
	sp_keyword("mod", MOD);
	sp_keyword("in", IN);
	sp_keyword("if", IF);
	sp_keyword("and", AND);
	sp_keyword("or", OR);
}

/*
 * Send an alias directive over to the symbol table manager.
 */

alias(new, old)
char *new, *old;
{
	if (old == NIL) {
		print_alias(dbtab, new);
	} else {
		enter_alias(dbtab, new, old);
	}
}

/*
 * Input file management routines, "yyin" is Lex's idea of
 * where the input comes from.
 */

#define MAXINPUT 10

LOCAL FILE *infp[MAXINPUT];
LOCAL FILE **curfp = &infp[0];

LOCAL BOOLEAN isnewfile;
LOCAL BOOLEAN firsttime;

/*
 * Initially, we set the input to the initfile if it exists.
 * If it does exist, we play a game or two to avoid generating
 * multiple prompts.
 */

initinput()
{
	FILE *fp;

	firsttime = FALSE;
	fp = fopen(initfile, "r");
	if (fp != NIL) {
		fclose(fp);
		setinput(initfile);
		if (!option('r')) {
			firsttime = TRUE;
		}
	}
	nlflag = TRUE;
}

/*
 * Set the input to the named file.  It is expected that the file exists
 * and is readable.
 */

setinput(filename)
char *filename;
{
	register FILE *fp;

	if ((fp = fopen(filename, "r")) == NIL) {
		error("can't open %s", filename);
	}
	if (curfp >= &infp[MAXINPUT]) {
		error("unreasonable input nesting on %s", filename);
	}
	*curfp++ = yyin;
	yyin = fp;
	isnewfile = TRUE;
}

BOOLEAN isstdin()
{
	return((BOOLEAN) (yyin == stdin));
}

LOCAL int input()
{
	register int c;

	if (isnewfile) {
		isnewfile = FALSE;
		return('\n');
	}
	while ((c = getc(yyin)) == EOF) {
		if (curfp == &infp[0]) {
			return(0);
		} else {
			fclose(yyin);
			yyin = *--curfp;
			if (yyin == stdin) {
				if (firsttime) {
					firsttime = FALSE;
				} else {
					prompt();
				}
			}
		}
	}
	return(c);
}

/*
 * Handle an input string by stripping the quotes and converting
 * two interior quotes to one.  Copy to newly allocated space and
 * return a pointer to it.
 *
 * The handling of strings here is not particularly efficient,
 * nor need it be.
 */

LOCAL char *pstring(p)
char *p;
{
	int i, len;
	char *r, *newp;

	len = strlen(p);
	r = newp = alloc(len - 2 + 1, char);
	for (i = 1; i < len - 1; i++) {
		if (p[i] == '\'' && p[i+1] == '\'') {
			i++;
		}
		*newp++ = p[i];
	}
	*newp = '\0';
	return(r);
}

/*
 * prompt for a command
 */

prompt()
{
	nlflag = FALSE;
	if (yyin == stdin) {
		printf("> ");
		fflush(stdout);
	}
}