libxkbcommon/src/xkbcomp/expr.c

/************************************************************
 Copyright (c) 1994 by Silicon Graphics Computer Systems, Inc.

 Permission to use, copy, modify, and distribute this
 software and its documentation for any purpose and 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, and that the name of Silicon Graphics not be
 used in advertising or publicity pertaining to distribution
 of the software without specific prior written permission.
 Silicon Graphics makes no representation about the suitability
 of this software for any purpose. It is provided "as is"
 without any express or implied warranty.

 SILICON GRAPHICS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
 SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
 GRAPHICS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
 DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION  WITH
 THE USE OR PERFORMANCE OF THIS SOFTWARE.

 ********************************************************/

#include "xkbcomp.h"
#include "xkbmisc.h"
#include "tokens.h"
#include "expr.h"
#include "vmod.h"

#include <ctype.h>

/***====================================================================***/

char *
exprOpText(unsigned type)
{
    static char buf[32];

    switch (type)
    {
    case ExprValue:
        strcpy(buf, "literal");
        break;
    case ExprIdent:
        strcpy(buf, "identifier");
        break;
    case ExprActionDecl:
        strcpy(buf, "action declaration");
        break;
    case ExprFieldRef:
        strcpy(buf, "field reference");
        break;
    case ExprArrayRef:
        strcpy(buf, "array reference");
        break;
    case ExprKeysymList:
        strcpy(buf, "list of keysyms");
        break;
    case ExprActionList:
        strcpy(buf, "list of actions");
        break;
    case OpAdd:
        strcpy(buf, "addition");
        break;
    case OpSubtract:
        strcpy(buf, "subtraction");
        break;
    case OpMultiply:
        strcpy(buf, "multiplication");
        break;
    case OpDivide:
        strcpy(buf, "division");
        break;
    case OpAssign:
        strcpy(buf, "assignment");
        break;
    case OpNot:
        strcpy(buf, "logical not");
        break;
    case OpNegate:
        strcpy(buf, "arithmetic negation");
        break;
    case OpInvert:
        strcpy(buf, "bitwise inversion");
        break;
    case OpUnaryPlus:
        strcpy(buf, "plus sign");
        break;
    default:
        snprintf(buf, sizeof(buf), "illegal(%d)", type);
        break;
    }
    return buf;
}

static char *
exprTypeText(unsigned type)
{
    static char buf[20];

    switch (type)
    {
    case TypeUnknown:
        strcpy(buf, "unknown");
        break;
    case TypeBoolean:
        strcpy(buf, "boolean");
        break;
    case TypeInt:
        strcpy(buf, "int");
        break;
    case TypeString:
        strcpy(buf, "string");
        break;
    case TypeAction:
        strcpy(buf, "action");
        break;
    case TypeKeyName:
        strcpy(buf, "keyname");
        break;
    default:
        snprintf(buf, sizeof(buf), "illegal(%d)", type);
        break;
    }
    return buf;
}

int
ExprResolveLhs(ExprDef * expr,
               ExprResult * elem_rtrn,
               ExprResult * field_rtrn, ExprDef ** index_rtrn)
{
    switch (expr->op)
    {
    case ExprIdent:
        elem_rtrn->str = NULL;
        field_rtrn->str = XkbcAtomGetString(expr->value.str);
        *index_rtrn = NULL;
        return True;
    case ExprFieldRef:
        elem_rtrn->str = XkbcAtomGetString(expr->value.field.element);
        field_rtrn->str = XkbcAtomGetString(expr->value.field.field);
        *index_rtrn = NULL;
        return True;
    case ExprArrayRef:
        elem_rtrn->str = XkbcAtomGetString(expr->value.array.element);
        field_rtrn->str = XkbcAtomGetString(expr->value.array.field);
        *index_rtrn = expr->value.array.entry;
        return True;
    }
    WSGO("Unexpected operator %d in ResolveLhs\n", expr->op);
    return False;
}

Bool
SimpleLookup(char * priv,
             uint32_t elem, uint32_t field, unsigned type, ExprResult * val_rtrn)
{
    LookupEntry *entry;
    const char *str;

    if ((priv == NULL) ||
        (field == None) || (elem != None) ||
        ((type != TypeInt) && (type != TypeFloat)))
    {
        return False;
    }
    str = XkbcAtomText(field);
    for (entry = (LookupEntry *) priv;
         (entry != NULL) && (entry->name != NULL); entry++)
    {
        if (uStrCaseCmp(str, entry->name) == 0)
        {
            val_rtrn->uval = entry->result;
            if (type == TypeFloat)
                val_rtrn->uval *= XkbGeomPtsPerMM;
            return True;
        }
    }
    return False;
}

Bool
RadioLookup(char * priv,
            uint32_t elem, uint32_t field, unsigned type, ExprResult * val_rtrn)
{
    const char *str;
    int rg;

    if ((field == None) || (elem != None) || (type != TypeInt))
        return False;
    str = XkbcAtomText(field);
    if (str)
    {
        if (uStrCasePrefix("group", str))
            str += strlen("group");
        else if (uStrCasePrefix("radiogroup", str))
            str += strlen("radiogroup");
        else if (uStrCasePrefix("rg", str))
            str += strlen("rg");
        else if (!isdigit(str[0]))
            str = NULL;
    }
    if ((!str) || (sscanf(str, "%i", &rg) < 1) || (rg < 1)
        || (rg > XkbMaxRadioGroups))
        return False;
    val_rtrn->uval = rg;
    return True;
}

static LookupEntry modIndexNames[] = {
    {"shift", ShiftMapIndex},
    {"control", ControlMapIndex},
    {"lock", LockMapIndex},
    {"mod1", Mod1MapIndex},
    {"mod2", Mod2MapIndex},
    {"mod3", Mod3MapIndex},
    {"mod4", Mod4MapIndex},
    {"mod5", Mod5MapIndex},
    {"none", XkbNoModifier},
    {NULL, 0}
};

int
LookupModIndex(char * priv,
               uint32_t elem, uint32_t field, unsigned type, ExprResult * val_rtrn)
{
    return SimpleLookup((char *) modIndexNames, elem, field, type,
                        val_rtrn);
}

static int
LookupModMask(char * priv,
              uint32_t elem, uint32_t field, unsigned type, ExprResult * val_rtrn)
{
    char *str;
    Bool ret = True;

    if ((elem != None) || (type != TypeInt))
        return False;
    str = XkbcAtomGetString(field);
    if (str == NULL)
        return False;
    if (uStrCaseCmp(str, "all") == 0)
        val_rtrn->uval = 0xff;
    else if (uStrCaseCmp(str, "none") == 0)
        val_rtrn->uval = 0;
    else if (LookupModIndex(priv, elem, field, type, val_rtrn))
        val_rtrn->uval = (1 << val_rtrn->uval);
    else if (priv != NULL)
    {
        LookupPriv *lpriv = (LookupPriv *) priv;
        if ((lpriv->chain == NULL) ||
            (!(*lpriv->chain) (lpriv->chainPriv, elem, field, type,
                               val_rtrn)))
            ret = False;
    }
    else
        ret = False;
    free(str);
    return ret;
}

int
ExprResolveModMask(ExprDef * expr,
                   ExprResult * val_rtrn)
{
    LookupPriv priv;

    priv.priv = NULL;
    priv.chain = NULL;
    priv.chainPriv = NULL;
    return ExprResolveMask(expr, val_rtrn, LookupModMask, (char *) & priv);
}

int
ExprResolveVModMask(ExprDef * expr,
                    ExprResult * val_rtrn,
                    struct xkb_desc *xkb)
{
    LookupPriv priv;

    priv.priv = NULL;
    priv.chain = LookupVModMask;
    priv.chainPriv = (char *) xkb;
    return ExprResolveMask(expr, val_rtrn, LookupModMask, (char *) & priv);
}

int
ExprResolveBoolean(ExprDef * expr,
                   ExprResult * val_rtrn)
{
    int ok = 0;
    const char *bogus = NULL;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type != TypeBoolean)
        {
            ERROR
                ("Found constant of type %s where boolean was expected\n",
                 exprTypeText(expr->type));
            return False;
        }
        val_rtrn->ival = expr->value.ival;
        return True;
    case ExprIdent:
        bogus = XkbcAtomText(expr->value.str);
        if (bogus)
        {
            if ((uStrCaseCmp(bogus, "true") == 0) ||
                (uStrCaseCmp(bogus, "yes") == 0) ||
                (uStrCaseCmp(bogus, "on") == 0))
            {
                val_rtrn->uval = 1;
                return True;
            }
            else if ((uStrCaseCmp(bogus, "false") == 0) ||
                     (uStrCaseCmp(bogus, "no") == 0) ||
                     (uStrCaseCmp(bogus, "off") == 0))
            {
                val_rtrn->uval = 0;
                return True;
            }
        }
        ERROR("Identifier \"%s\" of type int is unknown\n",
              XkbcAtomText(expr->value.str));
        return False;
    case ExprFieldRef:
        ERROR("Default \"%s.%s\" of type boolean is unknown\n",
              XkbcAtomText(expr->value.field.element),
              XkbcAtomText(expr->value.field.field));
        return False;
    case OpInvert:
    case OpNot:
        ok = ExprResolveBoolean(expr, val_rtrn);
        if (ok)
            val_rtrn->uval = !val_rtrn->uval;
        return ok;
    case OpAdd:
        if (bogus == NULL)
            bogus = "Addition";
    case OpSubtract:
        if (bogus == NULL)
            bogus = "Subtraction";
    case OpMultiply:
        if (bogus == NULL)
            bogus = "Multiplication";
    case OpDivide:
        if (bogus == NULL)
            bogus = "Division";
    case OpAssign:
        if (bogus == NULL)
            bogus = "Assignment";
    case OpNegate:
        if (bogus == NULL)
            bogus = "Negation";
        ERROR("%s of boolean values not permitted\n", bogus);
        break;
    case OpUnaryPlus:
        ERROR("Unary \"+\" operator not permitted for boolean values\n");
        break;
    default:
        WSGO("Unknown operator %d in ResolveBoolean\n", expr->op);
        break;
    }
    return False;
}

int
ExprResolveFloat(ExprDef * expr,
                 ExprResult * val_rtrn)
{
    int ok = 0;
    ExprResult leftRtrn, rightRtrn;
    ExprDef *left, *right;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type == TypeString)
        {
            const char *str;
            str = XkbcAtomText(expr->value.str);
            if ((str != NULL) && (strlen(str) == 1))
            {
                val_rtrn->uval = str[0] * XkbGeomPtsPerMM;
                return True;
            }
        }
        if ((expr->type != TypeInt) && (expr->type != TypeFloat))
        {
            ERROR("Found constant of type %s, expected a number\n",
                   exprTypeText(expr->type));
            return False;
        }
        val_rtrn->ival = expr->value.ival;
        if (expr->type == TypeInt)
            val_rtrn->ival *= XkbGeomPtsPerMM;
        return True;
    case ExprIdent:
        ERROR("Numeric identifier \"%s\" unknown\n",
              XkbcAtomText(expr->value.str));
        return ok;
    case ExprFieldRef:
        ERROR("Numeric default \"%s.%s\" unknown\n",
              XkbcAtomText(expr->value.field.element),
              XkbcAtomText(expr->value.field.field));
        return ok;
    case OpAdd:
    case OpSubtract:
    case OpMultiply:
    case OpDivide:
        left = expr->value.binary.left;
        right = expr->value.binary.right;
        if (ExprResolveFloat(left, &leftRtrn) &&
            ExprResolveFloat(right, &rightRtrn))
        {
            switch (expr->op)
            {
            case OpAdd:
                val_rtrn->ival = leftRtrn.ival + rightRtrn.ival;
                break;
            case OpSubtract:
                val_rtrn->ival = leftRtrn.ival - rightRtrn.ival;
                break;
            case OpMultiply:
                val_rtrn->ival = leftRtrn.ival * rightRtrn.ival;
                break;
            case OpDivide:
                val_rtrn->ival = leftRtrn.ival / rightRtrn.ival;
                break;
            }
            return True;
        }
        return False;
    case OpAssign:
        WSGO("Assignment operator not implemented yet\n");
        break;
    case OpNot:
        ERROR("The ! operator cannot be applied to a number\n");
        return False;
    case OpInvert:
    case OpNegate:
        left = expr->value.child;
        if (ExprResolveFloat(left, &leftRtrn))
        {
            if (expr->op == OpNegate)
                val_rtrn->ival = -leftRtrn.ival;
            else
                val_rtrn->ival = ~leftRtrn.ival;
            return True;
        }
        return False;
    case OpUnaryPlus:
        left = expr->value.child;
        return ExprResolveFloat(left, val_rtrn);
    default:
        WSGO("Unknown operator %d in ResolveFloat\n", expr->op);
        break;
    }
    return False;
}

int
ExprResolveKeyCode(ExprDef * expr,
                   ExprResult * val_rtrn)
{
    ExprResult leftRtrn, rightRtrn;
    ExprDef *left, *right;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type != TypeInt)
        {
            ERROR
                ("Found constant of type %s where an int was expected\n",
                 exprTypeText(expr->type));
            return False;
        }
        val_rtrn->uval = expr->value.uval;
        return True;
    case OpAdd:
    case OpSubtract:
    case OpMultiply:
    case OpDivide:
        left = expr->value.binary.left;
        right = expr->value.binary.right;
        if (ExprResolveKeyCode(left, &leftRtrn) &&
            ExprResolveKeyCode(right, &rightRtrn))
        {
            switch (expr->op)
            {
            case OpAdd:
                val_rtrn->uval = leftRtrn.uval + rightRtrn.uval;
                break;
            case OpSubtract:
                val_rtrn->uval = leftRtrn.uval - rightRtrn.uval;
                break;
            case OpMultiply:
                val_rtrn->uval = leftRtrn.uval * rightRtrn.uval;
                break;
            case OpDivide:
                val_rtrn->uval = leftRtrn.uval / rightRtrn.uval;
                break;
            }
            return True;
        }
        return False;
    case OpNegate:
        left = expr->value.child;
        if (ExprResolveKeyCode(left, &leftRtrn))
        {
            val_rtrn->uval = ~leftRtrn.uval;
            return True;
        }
        return False;
    case OpUnaryPlus:
        left = expr->value.child;
        return ExprResolveKeyCode(left, val_rtrn);
    default:
        WSGO("Unknown operator %d in ResolveInteger\n", expr->op);
        break;
    }
    return False;
}
int
ExprResolveInteger(ExprDef * expr,
                   ExprResult * val_rtrn,
                   IdentLookupFunc lookup, char * lookupPriv)
{
    int ok = 0;
    ExprResult leftRtrn, rightRtrn;
    ExprDef *left, *right;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type == TypeString)
        {
            const char *str;
            str = XkbcAtomText(expr->value.str);
            if (str != NULL)
                switch (strlen(str))
                {
                case 0:
                    val_rtrn->uval = 0;
                    return True;
                case 1:
                    val_rtrn->uval = str[0];
                    return True;
                default:
                    break;
                }
        }
        if ((expr->type != TypeInt) && (expr->type != TypeFloat))
        {
            ERROR
                ("Found constant of type %s where an int was expected\n",
                 exprTypeText(expr->type));
            return False;
        }
        val_rtrn->ival = expr->value.ival;
        if (expr->type == TypeFloat)
            val_rtrn->ival /= XkbGeomPtsPerMM;
        return True;
    case ExprIdent:
        if (lookup)
        {
            ok = (*lookup) (lookupPriv,
                            None, expr->value.str, TypeInt, val_rtrn);
        }
        if (!ok)
            ERROR("Identifier \"%s\" of type int is unknown\n",
                   XkbcAtomText(expr->value.str));
        return ok;
    case ExprFieldRef:
        if (lookup)
        {
            ok = (*lookup) (lookupPriv,
                            expr->value.field.element,
                            expr->value.field.field, TypeInt, val_rtrn);
        }
        if (!ok)
            ERROR("Default \"%s.%s\" of type int is unknown\n",
                   XkbcAtomText(expr->value.field.element),
                   XkbcAtomText(expr->value.field.field));
        return ok;
    case OpAdd:
    case OpSubtract:
    case OpMultiply:
    case OpDivide:
        left = expr->value.binary.left;
        right = expr->value.binary.right;
        if (ExprResolveInteger(left, &leftRtrn, lookup, lookupPriv) &&
            ExprResolveInteger(right, &rightRtrn, lookup, lookupPriv))
        {
            switch (expr->op)
            {
            case OpAdd:
                val_rtrn->ival = leftRtrn.ival + rightRtrn.ival;
                break;
            case OpSubtract:
                val_rtrn->ival = leftRtrn.ival - rightRtrn.ival;
                break;
            case OpMultiply:
                val_rtrn->ival = leftRtrn.ival * rightRtrn.ival;
                break;
            case OpDivide:
                val_rtrn->ival = leftRtrn.ival / rightRtrn.ival;
                break;
            }
            return True;
        }
        return False;
    case OpAssign:
        WSGO("Assignment operator not implemented yet\n");
        break;
    case OpNot:
        left = expr->value.child;
        if (ExprResolveInteger(left, &leftRtrn, lookup, lookupPriv))
        {
            ERROR("The ! operator cannot be applied to an integer\n");
        }
        return False;
    case OpInvert:
    case OpNegate:
        left = expr->value.child;
        if (ExprResolveInteger(left, &leftRtrn, lookup, lookupPriv))
        {
            if (expr->op == OpNegate)
                val_rtrn->ival = -leftRtrn.ival;
            else
                val_rtrn->ival = ~leftRtrn.ival;
            return True;
        }
        return False;
    case OpUnaryPlus:
        left = expr->value.child;
        return ExprResolveInteger(left, val_rtrn, lookup, lookupPriv);
    default:
        WSGO("Unknown operator %d in ResolveInteger\n", expr->op);
        break;
    }
    return False;
}

int
ExprResolveString(ExprDef * expr,
                  ExprResult * val_rtrn,
                  IdentLookupFunc lookup, char * lookupPriv)
{
    int ok = 0;
    ExprResult leftRtrn, rightRtrn;
    ExprDef *left;
    ExprDef *right;
    char *bogus = NULL;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type != TypeString)
        {
            ERROR("Found constant of type %s, expected a string\n",
                   exprTypeText(expr->type));
            return False;
        }
        val_rtrn->str = XkbcAtomGetString(expr->value.str);
        if (val_rtrn->str == NULL)
            val_rtrn->str = strdup("");
        return True;
    case ExprIdent:
        if (lookup)
        {
            ok = (*lookup) (lookupPriv,
                            None, expr->value.str, TypeString, val_rtrn);
        }
        if (!ok)
            ERROR("Identifier \"%s\" of type string not found\n",
                   XkbcAtomText(expr->value.str));
        return ok;
    case ExprFieldRef:
        if (lookup)
        {
            ok = (*lookup) (lookupPriv,
                            expr->value.field.element,
                            expr->value.field.field, TypeString, val_rtrn);
        }
        if (!ok)
            ERROR("Default \"%s.%s\" of type string not found\n",
                   XkbcAtomText(expr->value.field.element),
                   XkbcAtomText(expr->value.field.field));
        return ok;
    case OpAdd:
        left = expr->value.binary.left;
        right = expr->value.binary.right;
        if (ExprResolveString(left, &leftRtrn, lookup, lookupPriv) &&
            ExprResolveString(right, &rightRtrn, lookup, lookupPriv))
        {
            int len;
            char *new;
            len = strlen(leftRtrn.str) + strlen(rightRtrn.str) + 1;
            new = (char *) malloc(len);
            if (new)
            {
                sprintf(new, "%s%s", leftRtrn.str, rightRtrn.str);
                free(leftRtrn.str);
                free(rightRtrn.str);
                val_rtrn->str = new;
                return True;
            }
            free(leftRtrn.str);
            free(rightRtrn.str);
        }
        return False;
    case OpSubtract:
        if (bogus == NULL)
            bogus = "Subtraction";
    case OpMultiply:
        if (bogus == NULL)
            bogus = "Multiplication";
    case OpDivide:
        if (bogus == NULL)
            bogus = "Division";
    case OpAssign:
        if (bogus == NULL)
            bogus = "Assignment";
    case OpNegate:
        if (bogus == NULL)
            bogus = "Negation";
    case OpInvert:
        if (bogus == NULL)
            bogus = "Bitwise complement";
        ERROR("%s of string values not permitted\n", bogus);
        return False;
    case OpNot:
        left = expr->value.child;
        if (ExprResolveString(left, &leftRtrn, lookup, lookupPriv))
        {
            ERROR("The ! operator cannot be applied to a string\n");
        }
        return False;
    case OpUnaryPlus:
        left = expr->value.child;
        if (ExprResolveString(left, &leftRtrn, lookup, lookupPriv))
        {
            ERROR("The + operator cannot be applied to a string\n");
        }
        return False;
    default:
        WSGO("Unknown operator %d in ResolveString\n", expr->op);
        break;
    }
    return False;
}

int
ExprResolveKeyName(ExprDef * expr,
                   ExprResult * val_rtrn)
{
    char *bogus = NULL;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type != TypeKeyName)
        {
            ERROR("Found constant of type %s, expected a key name\n",
                   exprTypeText(expr->type));
            return False;
        }
        memcpy(val_rtrn->keyName.name, expr->value.keyName, XkbKeyNameLength);
        return True;
    case ExprIdent:
        ERROR("Identifier \"%s\" of type string not found\n",
              XkbcAtomText(expr->value.str));
        return False;
    case ExprFieldRef:
        ERROR("Default \"%s.%s\" of type key name not found\n",
              XkbcAtomText(expr->value.field.element),
              XkbcAtomText(expr->value.field.field));
        return False;
    case OpAdd:
        if (bogus == NULL)
            bogus = "Addition";
    case OpSubtract:
        if (bogus == NULL)
            bogus = "Subtraction";
    case OpMultiply:
        if (bogus == NULL)
            bogus = "Multiplication";
    case OpDivide:
        if (bogus == NULL)
            bogus = "Division";
    case OpAssign:
        if (bogus == NULL)
            bogus = "Assignment";
    case OpNegate:
        if (bogus == NULL)
            bogus = "Negation";
    case OpInvert:
        if (bogus == NULL)
            bogus = "Bitwise complement";
        ERROR("%s of key name values not permitted\n", bogus);
        return False;
    case OpNot:
        ERROR("The ! operator cannot be applied to a key name\n");
        return False;
    case OpUnaryPlus:
        ERROR("The + operator cannot be applied to a key name\n");
        return False;
    default:
        WSGO("Unknown operator %d in ResolveKeyName\n", expr->op);
        break;
    }
    return False;
}

/***====================================================================***/

int
ExprResolveEnum(ExprDef * expr, ExprResult * val_rtrn, LookupEntry * values)
{
    if (expr->op != ExprIdent)
    {
        ERROR("Found a %s where an enumerated value was expected\n",
               exprOpText(expr->op));
        return False;
    }
    if (!SimpleLookup((char *) values, (uint32_t) None, expr->value.str,
                      (unsigned) TypeInt, val_rtrn))
    {
        int nOut = 0;
        ERROR("Illegal identifier %s (expected one of: ",
               XkbcAtomText(expr->value.str));
        while (values && values->name)
        {
            if (nOut != 0)
                INFO(", %s", values->name);
            else
                INFO("%s", values->name);
            values++;
            nOut++;
        }
        INFO(")\n");
        return False;
    }
    return True;
}

int
ExprResolveMask(ExprDef * expr,
                ExprResult * val_rtrn,
                IdentLookupFunc lookup, char * lookupPriv)
{
    int ok = 0;
    ExprResult leftRtrn, rightRtrn;
    ExprDef *left, *right;
    char *bogus = NULL;

    switch (expr->op)
    {
    case ExprValue:
        if (expr->type != TypeInt)
        {
            ERROR
                ("Found constant of type %s where a mask was expected\n",
                 exprTypeText(expr->type));
            return False;
        }
        val_rtrn->ival = expr->value.ival;
        return True;
    case ExprIdent:
        if (lookup)
        {
            ok = (*lookup) (lookupPriv,
                            None, expr->value.str, TypeInt, val_rtrn);
        }
        if (!ok)
            ERROR("Identifier \"%s\" of type int is unknown\n",
                   XkbcAtomText(expr->value.str));
        return ok;
    case ExprFieldRef:
        if (lookup)
        {
            ok = (*lookup) (lookupPriv,
                            expr->value.field.element,
                            expr->value.field.field, TypeInt, val_rtrn);
        }
        if (!ok)
            ERROR("Default \"%s.%s\" of type int is unknown\n",
                   XkbcAtomText(expr->value.field.element),
                   XkbcAtomText(expr->value.field.field));
        return ok;
    case ExprArrayRef:
        bogus = "array reference";
    case ExprActionDecl:
        if (bogus == NULL)
            bogus = "function use";
        ERROR("Unexpected %s in mask expression\n", bogus);
        ACTION("Expression ignored\n");
        return False;
    case OpAdd:
    case OpSubtract:
    case OpMultiply:
    case OpDivide:
        left = expr->value.binary.left;
        right = expr->value.binary.right;
        if (ExprResolveMask(left, &leftRtrn, lookup, lookupPriv) &&
            ExprResolveMask(right, &rightRtrn, lookup, lookupPriv))
        {
            switch (expr->op)
            {
            case OpAdd:
                val_rtrn->ival = leftRtrn.ival | rightRtrn.ival;
                break;
            case OpSubtract:
                val_rtrn->ival = leftRtrn.ival & (~rightRtrn.ival);
                break;
            case OpMultiply:
            case OpDivide:
                ERROR("Cannot %s masks\n",
                       expr->op == OpDivide ? "divide" : "multiply");
                ACTION("Illegal operation ignored\n");
                return False;
            }
            return True;
        }
        return False;
    case OpAssign:
        WSGO("Assignment operator not implemented yet\n");
        break;
    case OpInvert:
        left = expr->value.child;
        if (ExprResolveInteger(left, &leftRtrn, lookup, lookupPriv))
        {
            val_rtrn->ival = ~leftRtrn.ival;
            return True;
        }
        return False;
    case OpUnaryPlus:
    case OpNegate:
    case OpNot:
        left = expr->value.child;
        if (ExprResolveInteger(left, &leftRtrn, lookup, lookupPriv))
        {
            ERROR("The %s operator cannot be used with a mask\n",
                   (expr->op == OpNegate ? "-" : "!"));
        }
        return False;
    default:
        WSGO("Unknown operator %d in ResolveMask\n", expr->op);
        break;
    }
    return False;
}

int
ExprResolveKeySym(ExprDef * expr,
                  ExprResult * val_rtrn,
                  IdentLookupFunc lookup, char * lookupPriv)
{
    int ok = 0;
    uint32_t sym;

    if (expr->op == ExprIdent)
    {
        const char *str;
        str = XkbcAtomText(expr->value.str);
        if ((str != NULL) && ((sym = xkb_string_to_keysym(str)) != NoSymbol))
        {
            val_rtrn->uval = sym;
            return True;
        }
    }
    ok = ExprResolveInteger(expr, val_rtrn, lookup, lookupPriv);
    if ((ok) && (val_rtrn->uval < 10))
        val_rtrn->uval += '0';
    return ok;
}