File: scanner.c

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#ifndef lint
static char *RCSid = "$Id: scanner.c,v 1.56 1998/06/18 14:55:16 ddenholm Exp $";
#endif

/* GNUPLOT - scanner.c */

/*[
 * Copyright 1986 - 1993, 1998   Thomas Williams, Colin Kelley
 *
 * Permission to use, copy, and distribute this software and its
 * documentation for any purpose with or without fee is hereby granted,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.
 *
 * Permission to modify the software is granted, but not the right to
 * distribute the complete modified source code.  Modifications are to
 * be distributed as patches to the released version.  Permission to
 * distribute binaries produced by compiling modified sources is granted,
 * provided you
 *   1. distribute the corresponding source modifications from the
 *    released version in the form of a patch file along with the binaries,
 *   2. add special version identification to distinguish your version
 *    in addition to the base release version number,
 *   3. provide your name and address as the primary contact for the
 *    support of your modified version, and
 *   4. retain our contact information in regard to use of the base
 *    software.
 * Permission to distribute the released version of the source code along
 * with corresponding source modifications in the form of a patch file is
 * granted with same provisions 2 through 4 for binary distributions.
 *
 * This software is provided "as is" without express or implied warranty
 * to the extent permitted by applicable law.
]*/

#include "plot.h"

static int get_num __PROTO((char str[]));
static void substitute __PROTO((char *str, int max));

#ifdef AMIGA_AC_5
#define O_RDONLY	0
int open(const char * _name, int _mode, ...);
int close(int);
#endif /* AMIGA_AC_5 */

#ifdef VMS
#include <descrip.h>
#define MAILBOX "PLOT$MAILBOX"
#define pclose(f) fclose(f)
#endif /* VMS */


#define isident(c) (isalnum(c) || (c) == '_')

#ifndef STDOUT
#define STDOUT 1
#endif

#define LBRACE '{'
#define RBRACE '}'

#define APPEND_TOKEN {token[t_num].length++; current++;}

#define SCAN_IDENTIFIER while (isident(expression[current + 1]))\
				APPEND_TOKEN

static int t_num;	/* number of token I'm working on */

/*
 * scanner() breaks expression[] into lexical units, storing them in token[].
 *   The total number of tokens found is returned as the function value.
 *   Scanning will stop when '\0' is found in expression[], or when token[]
 *     is full.
 *
 *	 Scanning is performed by following rules:
 *
 *	Current char	token should contain
 *     -------------    -----------------------
 *	1.  alpha,_	all following alpha-numerics
 *	2.  digit	0 or more following digits, 0 or 1 decimal point,
 *				0 or more digits, 0 or 1 'e' or 'E',
 *				0 or more digits.
 *	3.  ^,+,-,/	only current char
 *	    %,~,(,)
 *	    [,],;,:,
 *	    ?,comma
 *          $           for using patch (div)
 *	4.  &,|,=,*	current char; also next if next is same
 *	5.  !,<,>	current char; also next if next is =
 *	6.  ", '	all chars up until matching quote
 *	7.  #		this token cuts off scanning of the line (DFK).
 *
 *			white space between tokens is ignored
 */
int scanner(expression)
char expression[];
{
register int current;	/* index of current char in expression[] */
register int quote;
char brace;

	for (current = t_num = 0; expression[current] != '\0'; current++) {
again:
		if(t_num+1>=token_table_size) {
		/* leave space for dummy end token */
			extend_token_table();
		}
		if (isspace(expression[current]))
			continue;						/* skip the whitespace */
		token[t_num].start_index = current;
		token[t_num].length = 1;
		token[t_num].is_token = TRUE;	/* to start with...*/

		if (expression[current] == '`') {
			substitute(&expression[current],MAX_LINE_LEN - current);
			goto again;
		}
		/* allow _ to be the first character of an identifier */
		if (isalpha(expression[current]) || expression[current] == '_') {
			SCAN_IDENTIFIER;
		} else if (isdigit(expression[current]) || expression[current] == '.'){
			token[t_num].is_token = FALSE;
			token[t_num].length = get_num(&expression[current]);
			current += (token[t_num].length - 1);
		} else if (expression[current] == LBRACE) {
			token[t_num].is_token = FALSE;
			token[t_num].l_val.type = CMPLX;
#ifdef __PUREC__
			{ char	l[80];
			if ((sscanf(&expression[++current],"%lf,%lf%[ }]s",
				&token[t_num].l_val.v.cmplx_val.real,
				&token[t_num].l_val.v.cmplx_val.imag,
				&l)	!= 3) || (!strchr(l, RBRACE))  )
					int_error("invalid complex constant",t_num);
			}
#else
			if ((sscanf(&expression[++current],"%lf , %lf %c",
				&token[t_num].l_val.v.cmplx_val.real,
				&token[t_num].l_val.v.cmplx_val.imag,
				&brace) != 3) || (brace != RBRACE))
					int_error("invalid complex constant",t_num);
#endif
			token[t_num].length += 2;
			while (expression[++current] != RBRACE) {
				token[t_num].length++;
				if (expression[current] == '\0')			/* { for vi % */
					int_error("no matching '}'", t_num);
			}
		} else if (expression[current] == '\'' || expression[current] == '\"'){
			token[t_num].length++;
			quote = expression[current];
			while (expression[++current] != quote) {
				if (!expression[current]) {
					expression[current] = quote;
					expression[current+1] = '\0';
					break;
                                } else if (expression[current]=='\\'
                                           && expression[current+1]) {
                                        current++;
                                        token[t_num].length+=2;
				} else
					token[t_num].length++;
			}
		} else switch (expression[current]) {
		     case '#':		/* DFK: add comments to gnuplot */
		    	  goto endline; /* ignore the rest of the line */
			case '^':
			case '+':
			case '-':
			case '/':
			case '%':
			case '~':
			case '(':
			case ')':
			case '[':
			case ']':
			case ';':
			case ':':
			case '?':
			case ',':
			case '$': /* div */
				break;
			case '&':
			case '|':
			case '=':
			case '*':
				if (expression[current] == expression[current + 1])
					APPEND_TOKEN;
				break;
			case '!':
			case '<':
			case '>':
				if (expression[current + 1] == '=')
					APPEND_TOKEN;
				break;
			default:
				int_error("invalid character",t_num);
			}
		++t_num;	/* next token if not white space */
	}

endline:					/* comments jump here to ignore line */

/* Now kludge an extra token which points to '\0' at end of expression[].
   This is useful so printerror() looks nice even if we've fallen off the
   line. */

		token[t_num].start_index = current;
		token[t_num].length = 0;
		/* print 3+4  then print 3+  is accepted without
		 * this, since string is ignored if it is not
		 * a token
		 */
		token[t_num].is_token=TRUE;
	return(t_num);
}


static int get_num(str)
char str[];
{
register int count = 0;
register long lval;

	token[t_num].is_token = FALSE;
	token[t_num].l_val.type = INTGR;		/* assume unless . or E found */
	while (isdigit(str[count]))
		count++;
	if (str[count] == '.') {
		token[t_num].l_val.type = CMPLX;
		while (isdigit(str[++count]))	/* swallow up digits until non-digit */
			;
		/* now str[count] is other than a digit */
	}
	if (str[count] == 'e' || str[count] == 'E') {
		token[t_num].l_val.type = CMPLX;
/* modified if statement to allow + sign in exponent
   rjl 26 July 1988 */
		count++;
		if (str[count] == '-' || str[count] == '+')
			count++;
		if (!isdigit(str[count])) {
			token[t_num].start_index += count;
			int_error("expecting exponent",t_num);
		}
		while (isdigit(str[++count]))
			;
	}
	if (token[t_num].l_val.type == INTGR) {
 		lval = atol(str);
		if ((token[t_num].l_val.v.int_val = lval) != lval)
			int_error("integer overflow; change to floating point",t_num);
	} else {
		token[t_num].l_val.v.cmplx_val.imag = 0.0;
		token[t_num].l_val.v.cmplx_val.real = atof(str);
	}
	return(count);
}

#if defined(VMS) || defined(PIPES) || (defined(ATARI) && defined(__PUREC__)) || (defined(MTOS) && defined(__PUREC__))

/* this really ought to make use of the dynamic-growth of the
 * input line in 3.6.  And it definitely should not have
 * static arrays !
 */
 
static void substitute(str,max)		/* substitute output from ` ` */
char *str;
int max;
{
register char *last;
register int i,c;
register FILE *f;
#ifdef AMIGA_AC_5
int fd;
#else /* AMIGA_AC_5 */
#if (defined(ATARI) || defined(MTOS)) && defined(__PUREC__)
char	*atari_tmpfile;
char	*atari_pgm[MAX_LINE_LEN+100];
#endif /* (ATARI || MTOS) && PUREC */
#endif /* AMIGA_AC_5 */
static char pgm[MAX_LINE_LEN+1],output[MAX_LINE_LEN+1];

#ifdef VMS
int chan, one = 1;
static $DESCRIPTOR(pgmdsc,pgm);
static $DESCRIPTOR(lognamedsc,MAILBOX);
#endif /* VMS */

	/* forgive missing closing backquote at end of line */
	i = 0;
	last = str;
	while (*++last) {
		if (*last == '`') {
			++last; /* move past it */
			break;
		}
		pgm[i++] = *last;
	}
	pgm[i] = '\0';		/* end with null */
	max -= strlen(last);	/* max is now the max length of output sub. */
  
#ifdef VMS
  	pgmdsc.dsc$w_length = i;
   	if (!((vaxc$errno = sys$crembx(0,&chan,0,0,0,0,&lognamedsc)) & 1))
   		os_error("sys$crembx failed",NO_CARET);
   
   	if (!((vaxc$errno = lib$spawn(&pgmdsc,0,&lognamedsc,&one)) & 1))
   		os_error("lib$spawn failed",NO_CARET);
   
   	if ((f = fopen(MAILBOX,"r")) == NULL)
   		os_error("mailbox open failed",NO_CARET);
#else /* VMS */
#if (defined(ATARI) || defined(MTOS)) && defined(__PUREC__)
		if (system(NULL) == 0)
			os_error("no command shell", NO_CARET);
		if ((strlen(atari_tmpfile) + strlen(pgm) + 5) > MAX_LINE_LEN+100)
			os_error("sorry, command to long", NO_CARET);
		atari_tmpfile = tmpnam(NULL);
		strcpy(atari_pgm, pgm);
		strcat(atari_pgm, " >> ");
		strcat(atari_pgm, atari_tmpfile);
		system(atari_pgm);
		if ((f = fopen(atari_tmpfile, "r")) == NULL)
#else
#ifdef AMIGA_AC_5
  	if ((fd = open(pgm,"O_RDONLY")) == -1)
#else /* AMIGA_AC_5 */
  	if ((f = popen(pgm,"r")) == NULL)
#endif /* AMIGA_AC_5 */
#endif	/* (ATARI || MTOS) && PUREC */
  		os_error("popen failed",NO_CARET);
#endif /* VMS */

	i = 0;
	while ((c = getc(f)) != EOF) {
		output[i++] = ((c == '\n') ? ' ' : c);	/* newlines become blanks*/
		if (i == max) {
#ifdef AMIGA_AC_5
			(void) close(fd);
#else /* AMIGA_AC_5 */
#if (defined(ATARI) || defined(MTOS)) && defined(__PUREC__)
			(void) fclose(f);
			(void) unlink(atari_tmpfile);
#else /* (ATARI || MTOS) && PUREC */
			(void) pclose(f);
#endif /* (ATARI || MTOS) && PUREC */
#endif /* AMIGA_AC_5 */
			int_error("substitution overflow", t_num);
		}
	}
#ifdef AMIGA_AC_5
	(void) close(fd);
#else
#if (defined(ATARI) || defined(MTOS)) && defined(__PUREC__)
	(void) fclose(f);
	(void) unlink(atari_tmpfile);
#else /* (ATARI || MTOS) && PUREC */
	(void) pclose(f);
#endif /* (ATARI || MTOS) && PUREC */
#endif /* AMIGA_AC_5 */

	if (i + strlen(last) > max)
		int_error("substitution overflowed rest of line", t_num);
	(void) strncpy(output+i,last,MAX_LINE_LEN-i);
									/* tack on rest of line to output */
	(void) strcpy(str,output);				/* now replace ` ` with output */
	screen_ok = FALSE;
}

#else /* VMS || PIPES || ATARI && PUREC */

static void substitute(str,max)
char *str;
int max;
{
	char line[100];

	int_error( strcat(strcpy(line,"substitution not supported by "),OS),t_num);
}
#endif /* unix || VMS || PIPES || ATARI && PUREC */