InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/bsd_srcs/usr.bin/window/parser1.c

C/C++ Source or Header | 1991-04-18 | 4.5 KB | 223 lines

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Edward Wang at The University of California, Berkeley.
 *
 * 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[] = "@(#)parser1.c    3.22 (Berkeley) 6/6/90";
#endif /* not lint */

#include "parser.h"

p_start()
{
    char flag = 1;

    (void) s_gettok();
    for (;;) {
        p_statementlist(flag);
        if (token == T_EOF || p_abort())
            break;
        flag = 0;
        p_synerror();
        while (token != T_EOL && token != T_EOF) {
            if (token == T_STR)
                str_free(token_str);
            (void) s_gettok();
        }
        if (token == T_EOL)
            (void) s_gettok();
        p_clearerr();
    }
}

p_statementlist(flag)
char flag;
{
    for (; p_statement(flag) >= 0; p_clearerr())
        ;
}

p_statement(flag)
char flag;
{
    switch (token) {
    case T_EOL:
        (void) s_gettok();
        return 0;
    case T_IF:
        return p_if(flag);
    default:
        return p_expression(flag);
    }
}

p_if(flag)
char flag;
{
    struct value t;
    char true = 0;

top:
    (void) s_gettok();

    if (p_expr(&t, flag) < 0) {
        p_synerror();
        return -1;
    }
    switch (t.v_type) {
    case V_NUM:
        true = !true && t.v_num != 0;
        break;
    case V_STR:
        p_error("if: Numeric value required.");
        str_free(t.v_str);
    case V_ERR:
        flag = 0;
        break;
    }

    if (token != T_THEN) {
        p_synerror();
        return -1;
    }

    (void) s_gettok();
    p_statementlist(flag && true);
    if (p_erred())
        return -1;

    if (token == T_ELSIF)
        goto top;

    if (token == T_ELSE) {
        (void) s_gettok();
        p_statementlist(flag && !true);
        if (p_erred())
            return -1;
    }

    if (token == T_ENDIF) {
        (void) s_gettok();
        return 0;
    }

    p_synerror();
    return -1;
}

p_expression(flag)
char flag;
{
    struct value t;
    char *cmd;
    int p_function(), p_assign();

    switch (token) {
    case T_NUM:
        t.v_type = V_NUM;
        t.v_num = token_num;
        (void) s_gettok();
        break;
    case T_STR:
        t.v_type = V_STR;
        t.v_str = token_str;
        (void) s_gettok();
        break;
    default:
        if (p_expr(&t, flag) < 0)
            return -1;
        if (token == T_EOF) {
            val_free(t);
            return 0;
        }
    }
    if (token != T_ASSIGN && p_convstr(&t) < 0)
        return -1;
    cmd = t.v_type == V_STR ? t.v_str : 0;
    if ((*(token == T_ASSIGN ? p_assign : p_function))(cmd, &t, flag) < 0) {
        if (cmd)
            str_free(cmd);
        return -1;
    }
    if (cmd)
        str_free(cmd);
    val_free(t);
    if (token == T_EOL)
        (void) s_gettok();
    else if (token != T_EOF) {
        p_synerror();
        return -1;
    }
    return 0;
}

p_convstr(v)
register struct value *v;
{
    if (v->v_type != V_NUM)
        return 0;
    if ((v->v_str = str_itoa(v->v_num)) == 0) {
        p_memerror();
        v->v_type = V_ERR;
        return -1;
    }
    v->v_type = V_STR;
    return 0;
}

p_synerror()
{
    if (!cx.x_synerred) {
        cx.x_synerred = cx.x_erred = 1;
        error("Syntax error.");
    }
}

/*VARARGS1*/
p_error(msg, a, b, c)
char *msg;
{
    if (!cx.x_erred) {
        cx.x_erred = 1;
        error(msg, a, b, c);
    }
}

p_memerror()
{
    cx.x_erred = cx.x_abort = 1;
    error("Out of memory.");
}