scanner.c

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/*
 * Copyright (c) 1983 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)scanner.c	5.3 (Berkeley) 6/1/90";
#endif /* not lint */

/*
 * Debugger scanner.
 */

#include "defs.h"
#include "scanner.h"
#include "main.h"
#include "keywords.h"
#include "tree.h"
#include "symbols.h"
#include "names.h"
#include "y.tab.h"

#ifndef public
typedef int Token;

#define MAXLINESIZE 10240

#endif

public String initfile = ".dbxinit";

typedef enum { WHITE, ALPHA, NUM, OTHER } Charclass;

private Charclass class[256 + 1];
private Charclass *lexclass = class + 1;

#define isdigit(c) (lexclass[c] == NUM)
#define isalnum(c) (lexclass[c] == ALPHA or lexclass[c] == NUM)
#define ishexdigit(c) ( \
    isdigit(c) or (c >= 'a' and c <= 'f') or (c >= 'A' and c <= 'F') \
)

public boolean chkalias;
public char scanner_linebuf[MAXLINESIZE];

private File in;
private char *curchar, *prevchar;

#define MAXINCLDEPTH 10

private struct {
    File savefile;
    Filename savefn;
    int savelineno;
} inclinfo[MAXINCLDEPTH];

private unsigned int curinclindex;

private Token getident();
private Token getnum();
private Token getstring();
private Boolean eofinput();
private char charcon();

private enterlexclass(class, s)
Charclass class;
String s;
{
    register char *p;

    for (p = s; *p != '\0'; p++) {
	lexclass[*p] = class;
    }
}

public scanner_init()
{
    register Integer i;

    for (i = 0; i < 257; i++) {
	class[i] = OTHER;
    }
    enterlexclass(WHITE, " \t");
    enterlexclass(ALPHA, "abcdefghijklmnopqrstuvwxyz");
    enterlexclass(ALPHA, "ABCDEFGHIJKLMNOPQRSTUVWXYZ_$");
    enterlexclass(NUM, "0123456789");
    in = stdin;
    errfilename = nil;
    errlineno = 0;
    curchar = scanner_linebuf;
    scanner_linebuf[0] = '\0';
    chkalias = true;
}

/*
 * Read a single token.
 *
 * The input is line buffered.  Tokens cannot cross line boundaries.
 *
 * There are two "modes" of operation:  one as in a compiler,
 * and one for reading shell-like syntax.  In the first mode
 * there is the additional choice of doing alias processing.
 */

private Boolean shellmode;

public Token yylex()
{
    register int c;
    register char *p;
    register Token t;
    String line;
    integer n;

    p = curchar;
    if (*p == '\0') {
	do {
	    if (isterm(in)) {
		printf("(%s) ", cmdname);
	    }
	    fflush(stdout);
	    line = fgets(scanner_linebuf, MAXLINESIZE, in);
	} while (line == nil and not eofinput());
	if (line == nil) {
	    c = EOF;
	} else {
	    p = scanner_linebuf;
	    while (lexclass[*p] == WHITE) {
		p++;
	    }
	    shellmode = false;
	}
	chkalias = true;
    } else {
	while (lexclass[*p] == WHITE) {
	    p++;
	}
    }
    curchar = p;
    prevchar = curchar;
    c = *p;
    if (lexclass[c] == ALPHA) {
	t = getident(chkalias);
    } else if (lexclass[c] == NUM) {
	if (shellmode) {
	    t = getident(chkalias);
	} else {
	    t = getnum();
	}
    } else {
	++curchar;
	switch (c) {
	    case '\n':
		t = '\n';
		if (errlineno != 0) {
		    errlineno++;
		}
		break;

	    case '"':
	    case '\'':
		t = getstring(c);
		break;

	    case '.':
		if (shellmode) {
		    --curchar;
		    t = getident(chkalias);
		} else if (isdigit(*curchar)) {
		    --curchar;
		    t = getnum();
		} else {
		    t = '.';
		}
		break;

	    case '-':
		if (shellmode) {
		    --curchar;
		    t = getident(chkalias);
		} else if (*curchar == '>') {
		    ++curchar;
		    t = ARROW;
		} else {
		    t = '-';
		}
		break;

	    case '#':
		if (not isterm(in)) {
		    *p = '\0';
		    curchar = p;
		    t = '\n';
		    ++errlineno;
		} else {
		    t = '#';
		}
		break;

	    case '\\':
		if (*(p+1) == '\n') {
		    n = MAXLINESIZE - (p - &scanner_linebuf[0]);
		    if (n > 1) {
			if (fgets(p, n, in) == nil) {
			    t = 0;
			} else {
			    curchar = p;
			    t = yylex();
			}
		    } else {
			t = '\\';
		    }
		} else {
		    t = '\\';
		}
		break;

	    case EOF:
		t = 0;
		break;

	    default:
		if (shellmode and index("!&*<>()[]", c) == nil) {
		    --curchar;
		    t = getident(chkalias);
		} else {
		    t = c;
		}
		break;
	}
    }
    chkalias = false;
#   ifdef LEXDEBUG
	if (lexdebug) {
	    fprintf(stderr, "yylex returns ");
	    print_token(stderr, t);
	    fprintf(stderr, "\n");
	}
#   endif
    return t;
}

/*
 * Put the given string before the current character
 * in the current line, thus inserting it into the input stream.
 */

public insertinput (s)
String s;
{
    register char *p, *q;
    int need, avail, shift;

    q = s;
    need = strlen(q);
    avail = curchar - &scanner_linebuf[0];
    if (need <= avail) {
	curchar = &scanner_linebuf[avail - need];
	p = curchar;
	while (*q != '\0') {
	    *p++ = *q++;
	}
    } else {
	p = curchar;
	while (*p != '\0') {
	    ++p;
	}
	shift = need - avail;
	if (p + shift >= &scanner_linebuf[MAXLINESIZE]) {
	    error("alias expansion too large");
	}
	for (;;) {
	    *(p + shift) = *p;
	    if (p == curchar) {
		break;
	    }
	    --p;
	}
	p = &scanner_linebuf[0];
	while (*q != '\0') {
	    *p++ = *q++;
	}
	curchar = &scanner_linebuf[0];
    }
}

/*
 * Get the actuals for a macro call.
 */

private String movetochar (str, c)
String str;
char c;
{
    register char *p;

    while (*p != c) {
	if (*p == '\0') {
	    error("missing ')' in macro call");
	} else if (*p == ')') {
	    error("not enough parameters in macro call");
	} else if (*p == ',') {
	    error("too many parameters in macro call");
	}
	++p;
    }
    return p;
}

private String *getactuals (n)
integer n;
{
    String *a;
    register char *p;
    int i;

    a = newarr(String, n);
    p = curchar;
    while (*p != '(') {
	if (lexclass[*p] != WHITE) {
	    error("missing actuals for macro");
	}
	++p;
    }
    ++p;
    for (i = 0; i < n - 1; i++) {
	a[i] = p;
	p = movetochar(p, ',');
	*p = '\0';
	++p;
    }
    a[n-1] = p;
    p = movetochar(p, ')');
    *p = '\0';
    curchar = p + 1;
    return a;
}

/*
 * Do command macro expansion, assuming curchar points to the beginning
 * of the actuals, and we are not in shell mode.
 */

private expand (pl, str)
List pl;
String str;
{
    char buf[4096], namebuf[100];
    register char *p, *q, *r;
    String *actual;
    Name n;
    integer i;
    boolean match;

    if (pl == nil) {
	insertinput(str);
    } else {
	actual = getactuals(list_size(pl));
	p = buf;
	q = str;
	while (*q != '\0') {
	    if (p >= &buf[4096]) {
		error("alias expansion too large");
	    }
	    if (lexclass[*q] == ALPHA) {
		r = namebuf;
		do {
		    *r++ = *q++;
		} while (isalnum(*q));
		*r = '\0';
		i = 0;
		match = false;
		foreach(Name, n, pl)
		    if (streq(ident(n), namebuf)) {
			match = true;
			break;
		    }
		    ++i;
		endfor
		if (match) {
		    r = actual[i];
		} else {
		    r = namebuf;
		}
		while (*r != '\0') {
		    *p++ = *r++;
		}
	    } else {
		*p++ = *q++;
	    }
	}
	*p = '\0';
	insertinput(buf);
    }
}

/*
 * Parser error handling.
 */

public yyerror(s)
String s;
{
    register char *p;