openenvutils/commandshell/shell/src/math.c
author William Roberts <williamr@symbian.org>
Fri, 23 Apr 2010 14:37:17 +0100
branchRCL_3
changeset 22 c82a39b81a38
parent 4 0fdb7f6b0309
permissions -rw-r--r--
Rework addition of Symbian splash screen to reduce the source impact (uses SVG from Bug 2414) Notes: by using the OPTION SOURCEDIR parameter in the mifconv extension instructions, I can arrange to use the same source file name in sfimage, without having to export over the original Nokia file. This means that the name inside splashscreen.mbg is the same, which removes the need for the conditional compilation in SplashScreen.cpp, and gets rid of sf_splashscreen.mmp.

/*
* Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
* All rights reserved.
* This component and the accompanying materials are made available
* under the terms of "Eclipse Public License v1.0"
* which accompanies this distribution, and is available
* at the URL "http://www.eclipse.org/legal/epl-v10.html".
*
* Initial Contributors:
* Nokia Corporation - initial contribution.
*
* Contributors:
*
* Description:
*
*/


/*
 * This file is part of zsh, the Z shell.
 *
 * Copyright (c) 1992-1997 Paul Falstad
 * All rights reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and to distribute modified versions of this software for any
 * purpose, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * In no event shall Paul Falstad or the Zsh Development Group be liable
 * to any party for direct, indirect, special, incidental, or consequential
 * damages arising out of the use of this software and its documentation,
 * even if Paul Falstad and the Zsh Development Group have been advised of
 * the possibility of such damage.
 *
 * Paul Falstad and the Zsh Development Group specifically disclaim any
 * warranties, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose.  The software
 * provided hereunder is on an "as is" basis, and Paul Falstad and the
 * Zsh Development Group have no obligation to provide maintenance,
 * support, updates, enhancements, or modifications.
 *
 */

#include "zsh.mdh"
#include "math.pro"

#include <math.h>

#ifdef __SYMBIAN32__
#ifdef __WINSCW__
#pragma warn_possunwant off
#endif//__WINSCW__
#endif//__SYMBIAN32__

/* nonzero means we are not evaluating, just parsing */
 
/**/
int noeval;
 
/* integer zero */

/**/
mod_export mnumber zero_mnumber;

/* last input base we used */

/**/
int lastbase;
 
static char *ptr;

static mnumber yyval;
static char *yylval;

#define MAX_MLEVEL 256

static int mlevel = 0;

/* != 0 means recognize unary plus, minus, etc. */

static int unary = 1;

/* LR = left-to-right associativity *
 * RL = right-to-left associativity *
 * BOOL = short-circuiting boolean   */

#define LR   0x0000
#define RL   0x0001
#define BOOL 0x0002

#define MTYPE(x)  ((x) & 3)

/*
 * OP_A2    2 arguments
 * OP_A2IR  2 arguments, return integer
 * OP_A2IO  2 arguments, must be integer, return integer
 * OP_E2    2 arguments with assignment
 * OP_E2IO  2 arguments with assignment, must be integer, return integer
 * OP_OP    None of the above, but occurs where we are expecting an operator
 *          rather than an operand.
 * OP_OPF   Followed by an operator, not an operand.
 *
 * OP_A2*, OP_E2*, OP_OP*:
 *   Occur when we need an operator; the next object must be an operand,
 *   unless OP_OPF is also supplied.
 *
 * Others:
 *   Occur when we need an operand; the next object must also be an operand,
 *   unless OP_OPF is also supplied.
 */
#define OP_A2   0x0004
#define OP_A2IR 0x0008
#define OP_A2IO 0x0010
#define OP_E2   0x0020
#define OP_E2IO 0x0040
#define OP_OP   0x0080
#define OP_OPF  0x0100

#define M_INPAR 0
#define M_OUTPAR 1
#define NOT 2
#define COMP 3
#define POSTPLUS 4
#define POSTMINUS 5
#define UPLUS 6
#define UMINUS 7
#define AND 8
#define XOR 9
#define OR 10
#define MUL 11
#define DIV 12
#define MOD 13
#define PLUS 14
#define MINUS 15
#define SHLEFT 16
#define SHRIGHT 17
#define LES 18
#define LEQ 19
#define GRE 20
#define GEQ 21
#define DEQ 22
#define NEQ 23
#define DAND 24
#define DOR 25
#define DXOR 26
#define QUEST 27
#define COLON 28
#define EQ 29
#define PLUSEQ 30
#define MINUSEQ 31
#define MULEQ 32
#define DIVEQ 33
#define MODEQ 34
#define ANDEQ 35
#define XOREQ 36
#define OREQ 37
#define SHLEFTEQ 38
#define SHRIGHTEQ 39
#define DANDEQ 40
#define DOREQ 41
#define DXOREQ 42
#define COMMA 43
#define EOI 44
#define PREPLUS 45
#define PREMINUS 46
#define NUM 47
#define ID 48
#define POWER 49
#define CID 50
#define POWEREQ 51
#define FUNC 52
#define TOKCOUNT 53

/* precedences */

static int prec[TOKCOUNT] =
{
     1, 137,  2,  2,   2,
     2,   2,  2,  4,   5,
     6,   8,  8,  8,   9,
     9,   3,  3, 10,  10,
    10,  10, 11, 11,  12,
    13,  13, 14, 15,  16,
    16,  16, 16, 16,  16,
    16,  16, 16, 16,  16,
    16,  16, 16, 17, 200,
     2,   2,  0,  0,   7,
     0,  16, 0
};

#define TOPPREC 18
#define ARGPREC 16

static int type[TOKCOUNT] =
{
/*  0 */  LR, LR|OP_OP|OP_OPF, RL, RL, RL|OP_OP|OP_OPF,
/*  5 */  RL|OP_OP|OP_OPF, RL, RL, LR|OP_A2IO, LR|OP_A2IO,
/* 10 */  LR|OP_A2IO, LR|OP_A2, LR|OP_A2, LR|OP_A2IO, LR|OP_A2,
/* 15 */  LR|OP_A2, LR|OP_A2IO, LR|OP_A2IO, LR|OP_A2IR, LR|OP_A2IR,
/* 20 */  LR|OP_A2IR, LR|OP_A2IR, LR|OP_A2IR, LR|OP_A2IR, BOOL|OP_A2IO,
/* 25 */  BOOL|OP_A2IO, LR|OP_A2IO, RL|OP_OP, RL|OP_OP, RL|OP_E2,
/* 30 */  RL|OP_E2, RL|OP_E2, RL|OP_E2, RL|OP_E2, RL|OP_E2IO,
/* 35 */  RL|OP_E2IO, RL|OP_E2IO, RL|OP_E2IO, RL|OP_E2IO, RL|OP_E2IO,
/* 40 */  BOOL|OP_E2IO, BOOL|OP_E2IO, RL|OP_A2IO, RL|OP_A2, RL|OP_OP,
/* 45 */  RL, RL, LR|OP_OPF, LR|OP_OPF, RL|OP_A2,
/* 50 */  LR|OP_OPF, RL|OP_E2, LR|OP_OPF
};

static int
lexconstant(void)
{
#ifdef USE_LOCALE
    char *prev_locale;
#endif
    char *nptr;

    nptr = ptr;
    if (*nptr == '-')
	nptr++;

    if (*nptr == '0')
    {
	nptr++;
	if (*nptr == 'x' || *nptr == 'X') {
	    /* Let zstrtol parse number with base */
	    yyval.u.l = zstrtol(ptr, &ptr, 0);
	    /* Should we set lastbase here? */
	    lastbase = 16;
	    return NUM;
	}
	else if (isset(OCTALZEROES) &&
		 (memchr(nptr, '.', strlen(nptr)) == NULL) &&
		 idigit(*nptr)) {
	    yyval.u.l = zstrtol(ptr, &ptr, 0);
	    lastbase = 8;
	    return NUM;
	}
    }

    while (idigit(*nptr))
	nptr++;

    if (*nptr == '.' || *nptr == 'e' || *nptr == 'E') {
	/* it's a float */
	yyval.type = MN_FLOAT;
#ifdef USE_LOCALE
	prev_locale = dupstring(setlocale(LC_NUMERIC, NULL));
	setlocale(LC_NUMERIC, "POSIX");
#endif
	yyval.u.d = strtod(ptr, &nptr);
#ifdef USE_LOCALE
	if (prev_locale) setlocale(LC_NUMERIC, prev_locale);
#endif
	if (ptr == nptr || *nptr == '.') {
	    zerr("bad floating point constant", NULL, 0);
	    return EOI;
	}
	ptr = nptr;
    } else {
	/* it's an integer */
	yyval.u.l = zstrtol(ptr, &ptr, 10);

	if (*ptr == '#') {
	    ptr++;
	    yyval.u.l = zstrtol(ptr, &ptr, lastbase = yyval.u.l);
	}
    }
    return NUM;
}

/**/
int outputradix;

/**/
static int
zzlex(void)
{
    int cct = 0;
    yyval.type = MN_INTEGER;

    for (;; cct = 0)
	switch (*ptr++) {
	case '+':
	    if (*ptr == '+' && (unary || !ialnum(*ptr))) {
		ptr++;
		return (unary) ? PREPLUS : POSTPLUS;
	    }
	    if (*ptr == '=') {
		ptr++;
		return PLUSEQ;
	    }
	    return (unary) ? UPLUS : PLUS;
	case '-':
	    if (*ptr == '-' && (unary || !ialnum(*ptr))) {
		ptr++;
		return (unary) ? PREMINUS : POSTMINUS;
	    }
	    if (*ptr == '=') {
		ptr++;
		return MINUSEQ;
	    }
	    if (unary) {
		if (idigit(*ptr) || *ptr == '.') {
		    ptr--;
		    return lexconstant();
		} else
		    return UMINUS;
	    } else
		return MINUS;
	case '(':
	    return M_INPAR;
	case ')':
	    return M_OUTPAR;
	case '!':
	    if (*ptr == '=') {
		ptr++;
		return NEQ;
	    }
	    return NOT;
	case '~':
	    return COMP;
	case '&':
	    if (*ptr == '&') {
		if (*++ptr == '=') {
		    ptr++;
		    return DANDEQ;
		}
		return DAND;
	    } else if (*ptr == '=') {
		ptr++;
		return ANDEQ;
	    }
	    return AND;
	case '|':
	    if (*ptr == '|') {
		if (*++ptr == '=') {
		    ptr++;
		    return DOREQ;
		}
		return DOR;
	    } else if (*ptr == '=') {
		ptr++;
		return OREQ;
	    }
	    return OR;
	case '^':
	    if (*ptr == '^') {
		if (*++ptr == '=') {
		    ptr++;
		    return DXOREQ;
		}
		return DXOR;
	    } else if (*ptr == '=') {
		ptr++;
		return XOREQ;
	    }
	    return XOR;
	case '*':
	    if (*ptr == '*') {
		if (*++ptr == '=') {
		    ptr++;
		    return POWEREQ;
		}
		return POWER;
	    }
	    if (*ptr == '=') {
		ptr++;
		return MULEQ;
	    }
	    return MUL;
	case '/':
	    if (*ptr == '=') {
		ptr++;
		return DIVEQ;
	    }
	    return DIV;
	case '%':
	    if (*ptr == '=') {
		ptr++;
		return MODEQ;
	    }
	    return MOD;
	case '<':
	    if (*ptr == '<') {
		if (*++ptr == '=') {
		    ptr++;
		    return SHLEFTEQ;
		}
		return SHLEFT;
	    } else if (*ptr == '=') {
		ptr++;
		return LEQ;
	    }
	    return LES;
	case '>':
	    if (*ptr == '>') {
		if (*++ptr == '=') {
		    ptr++;
		    return SHRIGHTEQ;
		}
		return SHRIGHT;
	    } else if (*ptr == '=') {
		ptr++;
		return GEQ;
	    }
	    return GRE;
	case '=':
	    if (*ptr == '=') {
		ptr++;
		return DEQ;
	    }
	    return EQ;
	case '$':
	    yyval.u.l = mypid;
	    return NUM;
	case '?':
	    if (unary) {
		yyval.u.l = lastval;
		return NUM;
	    }
	    return QUEST;
	case ':':
	    return COLON;
	case ',':
	    return COMMA;
	case '\0':
	    ptr--;
	    return EOI;
	case '[':
	    {
		int n;

		if (idigit(*ptr)) {
		    n = zstrtol(ptr, &ptr, 10);
		    if (*ptr != ']' || !idigit(*++ptr)) {
			zerr("bad base syntax", NULL, 0);
			return EOI;
		    }
		    yyval.u.l = zstrtol(ptr, &ptr, lastbase = n);
		    return NUM;
		}
		if (*ptr == '#') {
		    n = 1;
		    if (*++ptr == '#') {
			n = -1;
			ptr++;
		    }
		    if (!idigit(*ptr))
			goto bofs;
		    outputradix = n * zstrtol(ptr, &ptr, 10);
		} else {
		    bofs:
		    zerr("bad output format specification", NULL, 0);
		    return EOI;
		}
		if(*ptr != ']')
			goto bofs;
		ptr++;
		break;
	    }
	case ' ':
	case '\t':
	case '\n':
	    break;
	/* Fall through! */
	default:
	    if (idigit(*--ptr) || *ptr == '.')
		return lexconstant();
	    if (*ptr == '#') {
		if (*++ptr == '\\' || *ptr == '#') {
		    int v;

		    ptr++;
		    if (!*ptr) {
			zerr("character missing after ##", NULL, 0);
			return EOI;
		    }
		    ptr = getkeystring(ptr, NULL, 6, &v);
		    yyval.u.l = v;
		    return NUM;
		}
		cct = 1;
	    }
	    if (iident(*ptr)) {
		int func = 0;
		char *p;

		p = ptr;
		while (iident(*++ptr));
		if (*ptr == '[' || (!cct && *ptr == '(')) {
		    char op = *ptr, cp = ((*ptr == '[') ? ']' : ')');
		    int l;
		    func = (op == '(');
		    for (ptr++, l = 1; *ptr && l; ptr++) {
			if (*ptr == op)
			    l++;
			if (*ptr == cp)
			    l--;
			if (*ptr == '\\' && ptr[1])
			    ptr++;
		    }
		}
		yylval = dupstrpfx(p, ptr - p);
		return (func ? FUNC : (cct ? CID : ID));
	    }
	    else if (cct) {
		yyval.u.l = poundgetfn(NULL);
		return NUM;
	    }
	    return EOI;
	}
}

/* the value stack */

#define STACKSZ 100
static int mtok;			/* last token */
static int sp = -1;			/* stack pointer */

struct mathvalue {
    char *lval;
    mnumber val;
};

static struct mathvalue *stack;

/**/
static void
push(mnumber val, char *lval, int getme)
{
    if (sp == STACKSZ - 1)
	zerr("stack overflow", NULL, 0);
    else
	sp++;
    stack[sp].val = val;
    stack[sp].lval = lval;
    if (getme)
	stack[sp].val.type = MN_UNSET;
}

/**/
static mnumber
pop(int noget)
{
    struct mathvalue *mv = stack+sp;

    if (mv->val.type == MN_UNSET && !noget)
	mv->val = getnparam(mv->lval);
    sp--;
    return errflag ? zero_mnumber : mv->val;
}

/**/
static mnumber
getcvar(char *s)
{
    char *t;
    mnumber mn;
    mn.type = MN_INTEGER;

    queue_signals();
    if (!(t = getsparam(s)))
	mn.u.l = 0;
    else
        mn.u.l = STOUC(*t == Meta ? t[1] ^ 32 : *t);
    unqueue_signals();
    return mn;
}


/**/
static mnumber
setvar(char *s, mnumber v)
{
    if (!s) {
	zerr("lvalue required", NULL, 0);
	v.type = MN_INTEGER;
	v.u.l = 0;
	return v;
    }
    if (noeval)
	return v;
    untokenize(s);
    setnparam(s, v);
    return v;
}


/**/
static mnumber
callmathfunc(char *o)
{
    MathFunc f;
    char *a, *n;
    static mnumber dummy;

    n = a = dupstring(o);

    while (*a != '(')
	a++;
    *a++ = '\0';
    a[strlen(a) - 1] = '\0';

    if ((f = getmathfunc(n, 1))) {
	if (f->flags & MFF_STR)
	    return f->sfunc(n, a, f->funcid);
	else {
	    int argc = 0;
	    mnumber *argv = NULL, *q;
	    LinkList l = newlinklist();
	    LinkNode node;

	    while (iblank(*a))
		a++;
	    while (*a) {
		if (*a) {
		    argc++;
 		    q = (mnumber *) zhalloc(sizeof(mnumber));
		    *q = mathevall(a, ARGPREC, &a);
		    addlinknode(l, q);
		    if (errflag || mtok != COMMA)
			break;
		}
	    }
	    if (*a && !errflag)
		zerr("bad math expression: illegal character: %c",
		     NULL, *a);
	    if (!errflag) {
		if (argc >= f->minargs && (f->maxargs < 0 ||
					   argc <= f->maxargs)) {
		    if (argc) {
			q = argv = (mnumber *)zhalloc(argc * sizeof(mnumber));
			for (node = firstnode(l); node; incnode(node))
			    *q++ = *(mnumber *)getdata(node);
		    }
		    return f->nfunc(n, argc, argv, f->funcid);
		} else
		    zerr("wrong number of arguments: %s", o, 0);
	    }
	}
    } else
	zerr("unknown function: %s", n, 0);

    dummy.type = MN_INTEGER;
    dummy.u.l = 0;

    return dummy;
}

/**/
static int
notzero(mnumber a)
{
    if ((a.type & MN_INTEGER) ? a.u.l == 0 : a.u.d == 0.0) {
	zerr("division by zero", NULL, 0);
	return 0;
    }
    return 1;
}

/* macro to pop three values off the value stack */

/**/
void
op(int what)
{
    mnumber a, b, c, *spval;
    char *lv;
    int tp = type[what];

    if (errflag)
	return;
    if (sp < 0) {
	zerr("bad math expression: stack empty", NULL, 0);
	return;
    }

    if (tp & (OP_A2|OP_A2IR|OP_A2IO|OP_E2|OP_E2IO)) {
	/* Make sure anyone seeing this message reports it. */
	DPUTS(sp < 1, "BUG: math: not enough wallabies in outback.");
	b = pop(0);
	a = pop(what == EQ);
	if (errflag)
	    return;

	if (tp & (OP_A2IO|OP_E2IO)) {
	    /* coerce to integers */
	    if (a.type & MN_FLOAT) {
		a.type = MN_INTEGER;
		a.u.l = (zlong)a.u.d;
	    }
	    if (b.type & MN_FLOAT) {
		b.type = MN_INTEGER;
		b.u.l = (zlong)b.u.d;
	    }
	} else if (a.type != b.type && what != COMMA &&
		   (a.type != MN_UNSET || what != EQ)) {
	    /*
	     * Different types, so coerce to float.
	     * It may happen during an assignment that the LHS
	     * variable is actually an integer, but there's still
	     * no harm in doing the arithmetic in floating point;
	     * the assignment will do the correct conversion.
	     * This way, if the parameter is actually a scalar, but
	     * used to contain an integer, we can write a float into it.
	     */
	    if (a.type & MN_INTEGER) {
		a.type = MN_FLOAT;
		a.u.d = (double)a.u.l;
	    }
	    if (b.type & MN_INTEGER) {
		b.type = MN_FLOAT;
		b.u.d = (double)b.u.l;
	    }
	}

	if (noeval) {
	    c.type = MN_INTEGER;
	    c.u.l = 0;
	} else {
	    /*
	     * type for operation: usually same as operands, but e.g.
	     * (a == b) returns int.
	     */
	    c.type = (tp & OP_A2IR) ? MN_INTEGER : a.type;

	    switch(what) {
	    case AND:
	    case ANDEQ:
		c.u.l = a.u.l & b.u.l;
		break;
	    case XOR:
	    case XOREQ:
		c.u.l = a.u.l ^ b.u.l;
		break;
	    case OR:
	    case OREQ:
		c.u.l = a.u.l | b.u.l;
		break;
	    case MUL:
	    case MULEQ:
		if (c.type == MN_FLOAT)
		    c.u.d = a.u.d * b.u.d;
		else
		    c.u.l = a.u.l * b.u.l;
		break;
	    case DIV:
	    case DIVEQ:
		if (!notzero(b))
		    return;
		if (c.type == MN_FLOAT)
		    c.u.d = a.u.d / b.u.d;
		else
		    c.u.l = a.u.l / b.u.l;
		break;
	    case MOD:
	    case MODEQ:
		if (!notzero(b))
		    return;
		c.u.l = a.u.l % b.u.l;
		break;
	    case PLUS:
	    case PLUSEQ:
		if (c.type == MN_FLOAT)
		    c.u.d = a.u.d + b.u.d;
		else
		    c.u.l = a.u.l + b.u.l;
		break;
	    case MINUS:
	    case MINUSEQ:
		if (c.type == MN_FLOAT)
		    c.u.d = a.u.d - b.u.d;
		else
		    c.u.l = a.u.l - b.u.l;
		break;
	    case SHLEFT:
	    case SHLEFTEQ:
		c.u.l = a.u.l << b.u.l;
		break;
	    case SHRIGHT:
	    case SHRIGHTEQ:
		c.u.l = a.u.l >> b.u.l;
		break;
	    case LES:
		c.u.l = (zlong)
		    (a.type == MN_FLOAT ? (a.u.d < b.u.d) : (a.u.l < b.u.l));
		break;
	    case LEQ:
		c.u.l = (zlong)
		    (a.type == MN_FLOAT ? (a.u.d <= b.u.d) : (a.u.l <= b.u.l));
		break;
	    case GRE:
		c.u.l = (zlong)
		    (a.type == MN_FLOAT ? (a.u.d > b.u.d) : (a.u.l > b.u.l));
		break;
	    case GEQ:
		c.u.l = (zlong)
		    (a.type == MN_FLOAT ? (a.u.d >= b.u.d) : (a.u.l >= b.u.l));
		break;
	    case DEQ:
		c.u.l = (zlong)
		    (a.type == MN_FLOAT ? (a.u.d == b.u.d) : (a.u.l == b.u.l));
		break;
	    case NEQ:
		c.u.l = (zlong)
		    (a.type == MN_FLOAT ? (a.u.d != b.u.d) : (a.u.l != b.u.l));
		break;
	    case DAND:
	    case DANDEQ:
		c.u.l = (zlong)(a.u.l && b.u.l);
		break;
	    case DOR:
	    case DOREQ:
		c.u.l = (zlong)(a.u.l || b.u.l);
		break;
	    case DXOR:
	    case DXOREQ:
		c.u.l = (zlong)((a.u.l && !b.u.l) || (!a.u.l && b.u.l));
		break;
	    case COMMA:
		c = b;
		break;
	    case POWER:
	    case POWEREQ:
		if (c.type == MN_INTEGER && b.u.l < 0) {
		    /* produces a real result, so cast to real. */
		    a.type = b.type = c.type = MN_FLOAT;
		    a.u.d = (double) a.u.l;
		    b.u.d = (double) b.u.l;
		}
		if (c.type == MN_INTEGER) {
		    for (c.u.l = 1; b.u.l--; c.u.l *= a.u.l);
		} else {
		    if (b.u.d <= 0 && !notzero(a))
			return;
		    if (a.u.d < 0) {
			/* Error if (-num ** b) and b is not an integer */
			double tst = (double)(zlong)b.u.d;
			if (tst != b.u.d) {
			    zerr("imaginary power", NULL, 0);
			    return;
			}
		    }
		    c.u.d = pow(a.u.d, b.u.d);
		}
		break;
	    case EQ:
		c = b;
		break;
	    }
	}
	if (tp & (OP_E2|OP_E2IO)) {
	    lv = stack[sp+1].lval;
	    push(setvar(lv,c), lv, 0);
	} else
	    push(c,NULL, 0);
	return;
    }

    spval = &stack[sp].val;
    if (stack[sp].val.type == MN_UNSET)
	*spval = getnparam(stack[sp].lval);
    switch (what) {
    case NOT:
	if (spval->type & MN_FLOAT) {
	    spval->u.l = !spval->u.d;
	    spval->type = MN_INTEGER;
	} else
	    spval->u.l = !spval->u.l;
	stack[sp].lval = NULL;
	break;
    case COMP:
	if (spval->type & MN_FLOAT) {
	    spval->u.l = ~((zlong)spval->u.d);
	    spval->type = MN_INTEGER;
	} else
	    spval->u.l = ~spval->u.l;
	stack[sp].lval = NULL;
	break;
    case POSTPLUS:
	a = *spval;
	if (spval->type & MN_FLOAT)
	    a.u.d++;
	else
	    a.u.l++;
	(void)setvar(stack[sp].lval, a);
	break;
    case POSTMINUS:
	a = *spval;
	if (spval->type & MN_FLOAT)
	    a.u.d--;
	else
	    a.u.l--;
	(void)setvar(stack[sp].lval, a);
	break;
    case UPLUS:
	stack[sp].lval = NULL;
	break;
    case UMINUS:
	if (spval->type & MN_FLOAT)
	    spval->u.d = -spval->u.d;
	else
	    spval->u.l = -spval->u.l;
	stack[sp].lval = NULL;
	break;
    case QUEST:
	DPUTS(sp < 2, "BUG: math: three shall be the number of the counting.");
	c = pop(0);
	b = pop(0);
	a = pop(0);
	if (errflag)
	    return;
	/* b and c can stay different types in this case. */
	push(((a.type & MN_FLOAT) ? a.u.d : a.u.l) ? b : c, NULL, 0);
	break;
    case COLON:
	zerr("':' without '?'", NULL, 0);
	break;
    case PREPLUS:
	if (spval->type & MN_FLOAT)
	    spval->u.d++;
	else
	    spval->u.l++;
	setvar(stack[sp].lval, *spval);
	break;
    case PREMINUS:
	if (spval->type & MN_FLOAT)
	    spval->u.d--;
	else
	    spval->u.l--;
	setvar(stack[sp].lval, *spval);
	break;
    default:
	zerr("out of integers", NULL, 0);
	return;
    }
}


/**/
static void
bop(int tk)
{
    mnumber *spval = &stack[sp].val;
    int tst;

    if (stack[sp].val.type == MN_UNSET)
	*spval = getnparam(stack[sp].lval);
    tst = (spval->type & MN_FLOAT) ? (zlong)spval->u.d : spval->u.l; 

    switch (tk) {
    case DAND:
    case DANDEQ:
	if (!tst)
	    noeval++;
	break;
    case DOR:
    case DOREQ:
	if (tst)
	    noeval++;
	break;
    };
}


/**/
static mnumber
mathevall(char *s, int prek, char **ep)
{
    int xlastbase, xnoeval, xunary;
    char *xptr;
    mnumber xyyval;
    char *xyylval;
    int xsp;
    struct mathvalue *xstack = 0, nstack[STACKSZ];
    mnumber ret;

    if (mlevel >= MAX_MLEVEL) {
	xyyval.type = MN_INTEGER;
	xyyval.u.l = 0;

	zerr("math recursion limit exceeded", NULL, 0);

	return xyyval;
    }
    if (mlevel++) {
	xlastbase = lastbase;
	xnoeval = noeval;
	xunary = unary;
	xptr = ptr;
	xyyval = yyval;
	xyylval = yylval;

	xsp = sp;
	xstack = stack;
    } else {
	xlastbase = xnoeval = xunary = xsp = 0;
	xyyval.type = MN_INTEGER;
	xyyval.u.l = 0;
	xyylval = NULL;
	xptr = NULL;
    }
    stack = nstack;
    lastbase = -1;
    ptr = s;
    sp = -1;
    unary = 1;
    stack[0].val.type = MN_INTEGER;
    stack[0].val.u.l = 0;
    mathparse(prek);
    *ep = ptr;
    DPUTS(!errflag && sp > 0,
	  "BUG: math: wallabies roaming too freely in outback");

    if (errflag) {
	ret.type = MN_INTEGER;
	ret.u.l = errflag;
    } else {
	if (stack[0].val.type == MN_UNSET)
	    ret = getnparam(stack[0].lval);
	else
	    ret = stack[0].val;
    }

    if (--mlevel) {
	lastbase = xlastbase;
	noeval = xnoeval;
	unary = xunary;
	ptr = xptr;
	yyval = xyyval;
	yylval = xyylval;

	sp = xsp;
	stack = xstack;
    }
    return ret;
}


/**/
mod_export mnumber
matheval(char *s)
{
    char *junk;
    mnumber x;
    int xmtok = mtok;
    /* maintain outputradix across levels of evaluation */
    if (!mlevel)
	outputradix = 0;

    if (!*s) {
	x.type = MN_INTEGER;
	x.u.l = 0;
	return x;
    }
    x = mathevall(s, TOPPREC, &junk);
    mtok = xmtok;
    if (*junk)
	zerr("bad math expression: illegal character: %c", NULL, *junk);
    return x;
}

/**/
mod_export zlong
mathevali(char *s)
{
    mnumber x = matheval(s);
    return (x.type & MN_FLOAT) ? (zlong)x.u.d : x.u.l;
}


/**/
zlong
mathevalarg(char *s, char **ss)
{
    mnumber x;
    int xmtok = mtok;

    x = mathevall(s, ARGPREC, ss);
    if (mtok == COMMA)
	(*ss)--;
    mtok = xmtok;
    return (x.type & MN_FLOAT) ? (zlong)x.u.d : x.u.l;
}

/*
 * Make sure we have an operator or an operand, whatever is expected.
 * For this purpose, unary operators constitute part of an operand.
 */

/**/
static void
checkunary(int mtokc, char *mptr)
{
    int errmsg = 0;
    int tp = type[mtokc];
    if (tp & (OP_A2|OP_A2IR|OP_A2IO|OP_E2|OP_E2IO|OP_OP)) {
	if (unary)
	    errmsg = 1;
    } else {
	if (!unary)
	    errmsg = 2;
    }
    if (errmsg) {
	char errbuf[80];
	int len, over = 0;
	while (inblank(*mptr))
	    mptr++;
	len = ztrlen(mptr);
	if (len > 10) {
	    len = 10;
	    over = 1;
	}
	sprintf(errbuf, "bad math expression: %s expected at `%%l%s'",
		errmsg == 2 ? "operator" : "operand",
		over ? "..." : ""); 
	zerr(errbuf, mptr, len);
    }
    unary = !(tp & OP_OPF);
}

/* operator-precedence parse the string and execute */

/**/
static void
mathparse(int pc)
{
    zlong q;
    int otok, onoeval;
    char *optr = ptr;

    if (errflag)
	return;
    mtok = zzlex();
    /* Handle empty input */
    if (pc == TOPPREC && mtok == EOI)
	return;
    checkunary(mtok, optr);
    while (prec[mtok] <= pc) {
	if (errflag)
	    return;
	switch (mtok) {
	case NUM:
	    push(yyval, NULL, 0);
	    break;
	case ID:
	    push(zero_mnumber, yylval, !noeval);
	    break;
	case CID:
	    push((noeval ? zero_mnumber : getcvar(yylval)), yylval, 0);
	    break;
	case FUNC:
	    push((noeval ? zero_mnumber : callmathfunc(yylval)), yylval, 0);
	    break;
	case M_INPAR:
	    mathparse(TOPPREC);
	    if (mtok != M_OUTPAR) {
		if (!errflag)
		    zerr("')' expected", NULL, 0);
		return;
	    }
	    break;
	case QUEST:
	    if (stack[sp].val.type == MN_UNSET)
		stack[sp].val = getnparam(stack[sp].lval);
	    q = (stack[sp].val.type == MN_FLOAT) ? (zlong)stack[sp].val.u.d :
		stack[sp].val.u.l;

	    if (!q)
		noeval++;
	    mathparse(prec[COLON] - 1);
	    if (!q)
		noeval--;
	    if (mtok != COLON) {
		if (!errflag)
		    zerr("':' expected", NULL, 0);
		return;
	    }
	    if (q)
		noeval++;
	    mathparse(prec[QUEST]);
	    if (q)
		noeval--;
	    op(QUEST);
	    continue;
	default:
	    otok = mtok;
	    onoeval = noeval;
	    if (MTYPE(type[otok]) == BOOL)
		bop(otok);
	    mathparse(prec[otok] - (MTYPE(type[otok]) != RL));
	    noeval = onoeval;
	    op(otok);
	    continue;
	}
	optr = ptr;
	mtok = zzlex();
	checkunary(mtok, optr);
    }
}