/*      @(#)parser1.c   8.1 (Berkeley) 6/6/93   */
/*      $NetBSD: parser1.c,v 1.6 2003/08/07 11:17:28 agc Exp $  */

/*
 * Copyright (c) 1983, 1993
 *      The 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. 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.
 */

#include "defs.h"
#include "parser.h"

void
p_start(void)
{
        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();
        }
}

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

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

int
p_if(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);
                /* FALLTHROUGH */
        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;
}

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

        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;
}

int
p_convstr(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;
}

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

void
p_error(const char *msg, ...)
{
        va_list ap;

        va_start(ap, msg);
        if (!cx.x_erred) {
                cx.x_erred = 1;
                verror(msg, ap);
        }
        va_end(ap);
}

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