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[micropolis] / src / tcl / tclcmdmz.c

/* 
 * tclCmdMZ.c --
 *
 *      This file contains the top-level command routines for most of
 *      the Tcl built-in commands whose names begin with the letters
 *      M to Z.  It contains only commands in the generic core (i.e.
 *      those that don't depend much upon UNIX facilities).
 *
 * Copyright 1987-1991 Regents of the University of California
 * 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.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 */

#ifndef lint
static char rcsid[] = "$Header: /user6/ouster/tcl/RCS/tclCmdMZ.c,v 1.13 92/04/23 11:07:54 ouster Exp $ SPRITE (Berkeley)";
#endif

#include "tclint.h"

/*
 * Structure used to hold information about variable traces:
 */

typedef struct {
    int flags;                  /* Operations for which Tcl command is
                                 * to be invoked. */
    int length;                 /* Number of non-NULL chars. in command. */
    char command[4];            /* Space for Tcl command to invoke.  Actual
                                 * size will be as large as necessary to
                                 * hold command.  This field must be the
                                 * last in the structure, so that it can
                                 * be larger than 4 bytes. */
} TraceVarInfo;

/*
 * Forward declarations for procedures defined in this file:
 */

static char *           TraceVarProc _ANSI_ARGS_((ClientData clientData,
                            Tcl_Interp *interp, char *name1, char *name2,
                            int flags));
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_RegexpCmd --
 *
 *      This procedure is invoked to process the "regexp" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_RegexpCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    int noCase = 0;
    int indices = 0;
    regexp *regexpPtr;
    char **argPtr, *string;
    int match, i;

    if (argc < 3) {
        wrongNumArgs:
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " ?-nocase? exp string ?matchVar? ?subMatchVar ",
                "subMatchVar ...?\"", (char *) NULL);
        return TCL_ERROR;
    }
    argPtr = argv+1;
    argc--;
    while ((argc > 0) && (argPtr[0][0] == '-')) {
        if (strcmp(argPtr[0], "-indices") == 0) {
            argPtr++;
            argc--;
            indices = 1;
        } else if (strcmp(argPtr[0], "-nocase") == 0) {
            argPtr++;
            argc--;
            noCase = 1;
        } else {
            break;
        }
    }
    if (argc < 2) {
        goto wrongNumArgs;
    }
    regexpPtr = TclCompileRegexp(interp, argPtr[0]);
    if (regexpPtr == NULL) {
        return TCL_ERROR;
    }

    /*
     * Convert the string to lower case, if desired, and perform
     * the match.
     */

    if (noCase) {
        register char *dst, *src;

        string = (char *) ckalloc((unsigned) (strlen(argPtr[1]) + 1));
        for (src = argPtr[1], dst = string; *src != 0; src++, dst++) {
            if (isupper(*src)) {
                *dst = tolower(*src);
            } else {
                *dst = *src;
            }
        }
        *dst = 0;
    } else {
        string = argPtr[1];
    }
    tclRegexpError = NULL;
    match = regexec(regexpPtr, string);
    if (string != argPtr[1]) {
        ckfree(string);
    }
    if (tclRegexpError != NULL) {
        Tcl_AppendResult(interp, "error while matching pattern: ",
                tclRegexpError, (char *) NULL);
        return TCL_ERROR;
    }
    if (!match) {
        interp->result = "0";
        return TCL_OK;
    }

    /*
     * If additional variable names have been specified, return
     * index information in those variables.
     */

    argc -= 2;
    if (argc > NSUBEXP) {
        interp->result = "too many substring variables";
        return TCL_ERROR;
    }
    for (i = 0; i < argc; i++) {
        char *result, info[50];

        if (regexpPtr->startp[i] == NULL) {
            if (indices) {
                result = Tcl_SetVar(interp, argPtr[i+2], "-1 -1", 0);
            } else {
                result = Tcl_SetVar(interp, argPtr[i+2], "", 0);
            }
        } else {
            if (indices) {
                sprintf(info, "%d %d", regexpPtr->startp[i] - string,
                        regexpPtr->endp[i] - string - 1);
                result = Tcl_SetVar(interp, argPtr[i+2], info, 0);
            } else {
                char savedChar, *first, *last;

                first = argPtr[1] + (regexpPtr->startp[i] - string);
                last = argPtr[1] + (regexpPtr->endp[i] - string);
                savedChar = *last;
                *last = 0;
                result = Tcl_SetVar(interp, argPtr[i+2], first, 0);
                *last = savedChar;
            }
        }
        if (result == NULL) {
            Tcl_AppendResult(interp, "couldn't set variable \"",
                    argPtr[i+2], "\"", (char *) NULL);
            return TCL_ERROR;
        }
    }
    interp->result = "1";
    return TCL_OK;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_RegsubCmd --
 *
 *      This procedure is invoked to process the "regsub" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_RegsubCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    int noCase = 0, all = 0;
    regexp *regexpPtr;
    char *string, *p, *firstChar, *newValue, **argPtr;
    int match, result, flags;
    register char *src, c;

    if (argc < 5) {
        wrongNumArgs:
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " ?-nocase? ?-all? exp string subSpec varName\"", (char *) NULL);
        return TCL_ERROR;
    }
    argPtr = argv+1;
    argc--;
    while (argPtr[0][0] == '-') {
        if (strcmp(argPtr[0], "-nocase") == 0) {
            argPtr++;
            argc--;
            noCase = 1;
        } else if (strcmp(argPtr[0], "-all") == 0) {
            argPtr++;
            argc--;
            all = 1;
        } else {
            break;
        }
    }
    if (argc != 4) {
        goto wrongNumArgs;
    }
    regexpPtr = TclCompileRegexp(interp, argPtr[0]);
    if (regexpPtr == NULL) {
        return TCL_ERROR;
    }

    /*
     * Convert the string to lower case, if desired.
     */

    if (noCase) {
        register char *dst;

        string = (char *) ckalloc((unsigned) (strlen(argPtr[1]) + 1));
        for (src = argPtr[1], dst = string; *src != 0; src++, dst++) {
            if (isupper(*src)) {
                *dst = tolower(*src);
            } else {
                *dst = *src;
            }
        }
        *dst = 0;
    } else {
        string = argPtr[1];
    }

    /*
     * The following loop is to handle multiple matches within the
     * same source string;  each iteration handles one match and its
     * corresponding substitution.  If "-all" hasn't been specified
     * then the loop body only gets executed once.
     */

    flags = 0;
    for (p = string; *p != 0; ) {
        tclRegexpError = NULL;
        match = regexec(regexpPtr, p);
        if (tclRegexpError != NULL) {
            Tcl_AppendResult(interp, "error while matching pattern: ",
                    tclRegexpError, (char *) NULL);
            result = TCL_ERROR;
            goto done;
        }
        if (!match) {
            break;
        }

        /*
         * Copy the portion of the source string before the match to the
         * result variable.
         */
    
        src = argPtr[1] + (regexpPtr->startp[0] - string);
        c = *src;
        *src = 0;
        newValue = Tcl_SetVar(interp, argPtr[3], argPtr[1] + (p - string),
                flags);
        *src = c;
        flags = TCL_APPEND_VALUE;
        if (newValue == NULL) {
            cantSet:
            Tcl_AppendResult(interp, "couldn't set variable \"",
                    argPtr[3], "\"", (char *) NULL);
            result = TCL_ERROR;
            goto done;
        }
    
        /*
         * Append the subSpec argument to the variable, making appropriate
         * substitutions.  This code is a bit hairy because of the backslash
         * conventions and because the code saves up ranges of characters in
         * subSpec to reduce the number of calls to Tcl_SetVar.
         */
    
        for (src = firstChar = argPtr[2], c = *src; c != 0; src++, c = *src) {
            int index;
    
            if (c == '&') {
                index = 0;
            } else if (c == '\\') {
                c = src[1];
                if ((c >= '0') && (c <= '9')) {
                    index = c - '0';
                } else if ((c == '\\') || (c == '&')) {
                    *src = c;
                    src[1] = 0;
                    newValue = Tcl_SetVar(interp, argPtr[3], firstChar,
                            TCL_APPEND_VALUE);
                    *src = '\\';
                    src[1] = c;
                    if (newValue == NULL) {
                        goto cantSet;
                    }
                    firstChar = src+2;
                    src++;
                    continue;
                } else {
                    continue;
                }
            } else {
                continue;
            }
            if (firstChar != src) {
                c = *src;
                *src = 0;
                newValue = Tcl_SetVar(interp, argPtr[3], firstChar,
                        TCL_APPEND_VALUE);
                *src = c;
                if (newValue == NULL) {
                    goto cantSet;
                }
            }
            if ((index < NSUBEXP) && (regexpPtr->startp[index] != NULL)
                    && (regexpPtr->endp[index] != NULL)) {
                char *first, *last, saved;
    
                first = argPtr[1] + (regexpPtr->startp[index] - string);
                last = argPtr[1] + (regexpPtr->endp[index] - string);
                saved = *last;
                *last = 0;
                newValue = Tcl_SetVar(interp, argPtr[3], first,
                        TCL_APPEND_VALUE);
                *last = saved;
                if (newValue == NULL) {
                    goto cantSet;
                }
            }
            if (*src == '\\') {
                src++;
            }
            firstChar = src+1;
        }
        if (firstChar != src) {
            if (Tcl_SetVar(interp, argPtr[3], firstChar,
                    TCL_APPEND_VALUE) == NULL) {
                goto cantSet;
            }
        }
        p = regexpPtr->endp[0];
        if (!all) {
            break;
        }
    }

    /*
     * If there were no matches at all, then return a "0" result.
     */

    if (p == string) {
        interp->result = "0";
        result = TCL_OK;
        goto done;
    }

    /*
     * Copy the portion of the source string after the last match to the
     * result variable.
     */

    if (*p != 0) {
        if (Tcl_SetVar(interp, argPtr[3], p, TCL_APPEND_VALUE) == NULL) {
            goto cantSet;
        }
    }
    interp->result = "1";
    result = TCL_OK;

    done:
    if (string != argPtr[1]) {
        ckfree(string);
    }
    return result;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_RenameCmd --
 *
 *      This procedure is invoked to process the "rename" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_RenameCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    register Command *cmdPtr;
    Interp *iPtr = (Interp *) interp;
    Tcl_HashEntry *hPtr;
    int new;

    if (argc != 3) {
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " oldName newName\"", (char *) NULL);
        return TCL_ERROR;
    }
    if (argv[2][0] == '\0') {
        if (Tcl_DeleteCommand(interp, argv[1]) != 0) {
            Tcl_AppendResult(interp, "can't delete \"", argv[1],
                    "\": command doesn't exist", (char *) NULL);
            return TCL_ERROR;
        }
        return TCL_OK;
    }
    hPtr = Tcl_FindHashEntry(&iPtr->commandTable, argv[2]);
    if (hPtr != NULL) {
        Tcl_AppendResult(interp, "can't rename to \"", argv[2],
                "\": command already exists", (char *) NULL);
        return TCL_ERROR;
    }
    hPtr = Tcl_FindHashEntry(&iPtr->commandTable, argv[1]);
    if (hPtr == NULL) {
        Tcl_AppendResult(interp, "can't rename \"", argv[1],
                "\":  command doesn't exist", (char *) NULL);
        return TCL_ERROR;
    }
    cmdPtr = (Command *) Tcl_GetHashValue(hPtr);
    Tcl_DeleteHashEntry(hPtr);
    hPtr = Tcl_CreateHashEntry(&iPtr->commandTable, argv[2], &new);
    Tcl_SetHashValue(hPtr, cmdPtr);
    return TCL_OK;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_ReturnCmd --
 *
 *      This procedure is invoked to process the "return" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_ReturnCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    if (argc > 2) {
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " ?value?\"", (char *) NULL);
        return TCL_ERROR;
    }
    if (argc == 2) {
        Tcl_SetResult(interp, argv[1], TCL_VOLATILE);
    }
    return TCL_RETURN;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_ScanCmd --
 *
 *      This procedure is invoked to process the "scan" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_ScanCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    int arg1Length;                     /* Number of bytes in argument to be
                                         * scanned.  This gives an upper limit
                                         * on string field sizes. */
#   define MAX_FIELDS 20
    typedef struct {
        char fmt;                       /* Format for field. */
        int size;                       /* How many bytes to allow for
                                         * field. */
        char *location;                 /* Where field will be stored. */
    } Field;
    Field fields[MAX_FIELDS];           /* Info about all the fields in the
                                         * format string. */
    register Field *curField;
    int numFields = 0;                  /* Number of fields actually
                                         * specified. */
    int suppress;                       /* Current field is assignment-
                                         * suppressed. */
    int totalSize = 0;                  /* Number of bytes needed to store
                                         * all results combined. */
    char *results;                      /* Where scanned output goes.  */
    int numScanned;                     /* sscanf's result. */
    register char *fmt;
    int i, widthSpecified;

    if (argc < 3) {
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " string format ?varName varName ...?\"", (char *) NULL);
        return TCL_ERROR;
    }

    /*
     * This procedure operates in four stages:
     * 1. Scan the format string, collecting information about each field.
     * 2. Allocate an array to hold all of the scanned fields.
     * 3. Call sscanf to do all the dirty work, and have it store the
     *    parsed fields in the array.
     * 4. Pick off the fields from the array and assign them to variables.
     */

    arg1Length = (strlen(argv[1]) + 4) & ~03;
    for (fmt = argv[2]; *fmt != 0; fmt++) {
        if (*fmt != '%') {
            continue;
        }
        fmt++;
        if (*fmt == '*') {
            suppress = 1;
            fmt++;
        } else {
            suppress = 0;
        }
        widthSpecified = 0;
        while (isdigit(*fmt)) {
            widthSpecified = 1;
            fmt++;
        }
        if (suppress) {
            continue;
        }
        if (numFields == MAX_FIELDS) {
            interp->result = "too many fields to scan";
            return TCL_ERROR;
        }
        curField = &fields[numFields];
        numFields++;
        switch (*fmt) {
            case 'D':
            case 'O':
            case 'X':
            case 'd':
            case 'o':
            case 'x':
                curField->fmt = 'd';
                curField->size = sizeof(int);
                break;

            case 's':
                curField->fmt = 's';
                curField->size = arg1Length;
                break;

            case 'c':
                if (widthSpecified) {
                    interp->result = 
                         "field width may not be specified in %c conversion";
                    return TCL_ERROR;
                }
                curField->fmt = 'c';
                curField->size = sizeof(int);
                break;

            case 'E':
            case 'F':
                curField->fmt = 'F';
                curField->size = sizeof(double);
                break;

            case 'e':
            case 'f':
                curField->fmt = 'f';
                curField->size = sizeof(float);
                break;

            case '[':
                curField->fmt = 's';
                curField->size = arg1Length;
                do {
                    fmt++;
                } while (*fmt != ']');
                break;

            default:
                sprintf(interp->result, "bad scan conversion character \"%c\"",
                        *fmt);
                return TCL_ERROR;
        }
        totalSize += curField->size;
    }

    if (numFields != (argc-3)) {
        interp->result =
                "different numbers of variable names and field specifiers";
        return TCL_ERROR;
    }

    /*
     * Step 2:
     */

    results = (char *) ckalloc((unsigned) totalSize);
    for (i = 0, totalSize = 0, curField = fields;
            i < numFields; i++, curField++) {
        curField->location = results + totalSize;
        totalSize += curField->size;
    }

    /*
     * Step 3:
     */

    numScanned = sscanf(argv[1], argv[2],
            fields[0].location, fields[1].location, fields[2].location,
            fields[3].location, fields[4].location, fields[5].location,
            fields[6].location, fields[7].location, fields[8].location,
            fields[9].location, fields[10].location, fields[11].location,
            fields[12].location, fields[13].location, fields[14].location,
            fields[15].location, fields[16].location, fields[17].location,
            fields[18].location, fields[19].location);

    /*
     * Step 4:
     */

    if (numScanned < numFields) {
        numFields = numScanned;
    }
    for (i = 0, curField = fields; i < numFields; i++, curField++) {
        switch (curField->fmt) {
            char string[120];

            case 'd':
                sprintf(string, "%d", *((int *) curField->location));
                if (Tcl_SetVar(interp, argv[i+3], string, 0) == NULL) {
                    storeError:
                    Tcl_AppendResult(interp,
                            "couldn't set variable \"", argv[i+3], "\"",
                            (char *) NULL);
                    ckfree((char *) results);
                    return TCL_ERROR;
                }
                break;

            case 'c':
                sprintf(string, "%d", *((char *) curField->location) & 0xff);
                if (Tcl_SetVar(interp, argv[i+3], string, 0) == NULL) {
                    goto storeError;
                }
                break;

            case 's':
                if (Tcl_SetVar(interp, argv[i+3], curField->location, 0)
                        == NULL) {
                    goto storeError;
                }
                break;

            case 'F':
                sprintf(string, "%g", *((double *) curField->location));
                if (Tcl_SetVar(interp, argv[i+3], string, 0) == NULL) {
                    goto storeError;
                }
                break;

            case 'f':
                sprintf(string, "%g", *((float *) curField->location));
                if (Tcl_SetVar(interp, argv[i+3], string, 0) == NULL) {
                    goto storeError;
                }
                break;
        }
    }
    ckfree(results);
    sprintf(interp->result, "%d", numScanned);
    return TCL_OK;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_SplitCmd --
 *
 *      This procedure is invoked to process the "split" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_SplitCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    char *splitChars;
    register char *p, *p2;
    char *elementStart;

    if (argc == 2) {
        splitChars = " \n\t\r";
    } else if (argc == 3) {
        splitChars = argv[2];
    } else {
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " string ?splitChars?\"", (char *) NULL);
        return TCL_ERROR;
    }

    /*
     * Handle the special case of splitting on every character.
     */

    if (*splitChars == 0) {
        char string[2];
        string[1] = 0;
        for (p = argv[1]; *p != 0; p++) {
            string[0] = *p;
            Tcl_AppendElement(interp, string, 0);
        }
        return TCL_OK;
    }

    /*
     * Normal case: split on any of a given set of characters.
     * Discard instances of the split characters.
     */

    for (p = elementStart = argv[1]; *p != 0; p++) {
        char c = *p;
        for (p2 = splitChars; *p2 != 0; p2++) {
            if (*p2 == c) {
                *p = 0;
                Tcl_AppendElement(interp, elementStart, 0);
                *p = c;
                elementStart = p+1;
                break;
            }
        }
    }
    if (p != argv[1]) {
        Tcl_AppendElement(interp, elementStart, 0);
    }
    return TCL_OK;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_StringCmd --
 *
 *      This procedure is invoked to process the "string" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_StringCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    int length;
    register char *p, c;
    int match;
    int first;
    int left = 0, right = 0;

    if (argc < 2) {
        Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                " option arg ?arg ...?\"", (char *) NULL);
        return TCL_ERROR;
    }
    c = argv[1][0];
    length = strlen(argv[1]);
    if ((c == 'c') && (strncmp(argv[1], "compare", length) == 0)) {
        if (argc != 4) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " compare string1 string2\"", (char *) NULL);
            return TCL_ERROR;
        }
        match = strcmp(argv[2], argv[3]);
        if (match > 0) {
            interp->result = "1";
        } else if (match < 0) {
            interp->result = "-1";
        } else {
            interp->result = "0";
        }
        return TCL_OK;
    } else if ((c == 'f') && (strncmp(argv[1], "first", length) == 0)) {
        if (argc != 4) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " first string1 string2\"", (char *) NULL);
            return TCL_ERROR;
        }
        first = 1;

        firstLast:
        match = -1;
        c = *argv[2];
        length = strlen(argv[2]);
        for (p = argv[3]; *p != 0; p++) {
            if (*p != c) {
                continue;
            }
            if (strncmp(argv[2], p, length) == 0) {
                match = p-argv[3];
                if (first) {
                    break;
                }
            }
        }
        sprintf(interp->result, "%d", match);
        return TCL_OK;
    } else if ((c == 'i') && (strncmp(argv[1], "index", length) == 0)) {
        int index;

        if (argc != 4) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " index string charIndex\"", (char *) NULL);
            return TCL_ERROR;
        }
        if (Tcl_GetInt(interp, argv[3], &index) != TCL_OK) {
            return TCL_ERROR;
        }
        if ((index >= 0) && (index < strlen(argv[2]))) {
            interp->result[0] = argv[2][index];
            interp->result[1] = 0;
        }
        return TCL_OK;
    } else if ((c == 'l') && (strncmp(argv[1], "last", length) == 0)
            && (length >= 2)) {
        if (argc != 4) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " last string1 string2\"", (char *) NULL);
            return TCL_ERROR;
        }
        first = 0;
        goto firstLast;
    } else if ((c == 'l') && (strncmp(argv[1], "length", length) == 0)
            && (length >= 2)) {
        if (argc != 3) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " length string\"", (char *) NULL);
            return TCL_ERROR;
        }
        sprintf(interp->result, "%d", strlen(argv[2]));
        return TCL_OK;
    } else if ((c == 'm') && (strncmp(argv[1], "match", length) == 0)) {
        if (argc != 4) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " match pattern string\"", (char *) NULL);
            return TCL_ERROR;
        }
        if (Tcl_StringMatch(argv[3], argv[2]) != 0) {
            interp->result = "1";
        } else {
            interp->result = "0";
        }
        return TCL_OK;
    } else if ((c == 'r') && (strncmp(argv[1], "range", length) == 0)) {
        int first, last, stringLength;

        if (argc != 5) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " range string first last\"", (char *) NULL);
            return TCL_ERROR;
        }
        stringLength = strlen(argv[2]);
        if (Tcl_GetInt(interp, argv[3], &first) != TCL_OK) {
            return TCL_ERROR;
        }
        if ((*argv[4] == 'e')
                && (strncmp(argv[4], "end", strlen(argv[4])) == 0)) {
            last = stringLength-1;
        } else {
            if (Tcl_GetInt(interp, argv[4], &last) != TCL_OK) {
                Tcl_ResetResult(interp);
                Tcl_AppendResult(interp,
                        "expected integer or \"end\" but got \"",
                        argv[4], "\"", (char *) NULL);
                return TCL_ERROR;
            }
        }
        if (first < 0) {
            first = 0;
        }
        if (last >= stringLength) {
            last = stringLength-1;
        }
        if (last >= first) {
            char saved, *p;

            p = argv[2] + last + 1;
            saved = *p;
            *p = 0;
            Tcl_SetResult(interp, argv[2] + first, TCL_VOLATILE);
            *p = saved;
        }
        return TCL_OK;
    } else if ((c == 't') && (strncmp(argv[1], "tolower", length) == 0)
            && (length >= 3)) {
        register char *p;

        if (argc != 3) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " tolower string\"", (char *) NULL);
            return TCL_ERROR;
        }
        Tcl_SetResult(interp, argv[2], TCL_VOLATILE);
        for (p = interp->result; *p != 0; p++) {
            if (isupper(*p)) {
                *p = tolower(*p);
            }
        }
        return TCL_OK;
    } else if ((c == 't') && (strncmp(argv[1], "toupper", length) == 0)
            && (length >= 3)) {
        register char *p;

        if (argc != 3) {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " toupper string\"", (char *) NULL);
            return TCL_ERROR;
        }
        Tcl_SetResult(interp, argv[2], TCL_VOLATILE);
        for (p = interp->result; *p != 0; p++) {
            if (islower(*p)) {
                *p = toupper(*p);
            }
        }
        return TCL_OK;
    } else if ((c == 't') && (strncmp(argv[1], "trim", length) == 0)
            && (length == 4)) {
        char *trimChars;
        register char *p, *checkPtr;

        left = right = 1;

        trim:
        if (argc == 4) {
            trimChars = argv[3];
        } else if (argc == 3) {
            trimChars = " \t\n\r";
        } else {
            Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
                    " ", argv[1], " string ?chars?\"", (char *) NULL);
            return TCL_ERROR;
        }
        p = argv[2];
        if (left) {
            for (c = *p; c != 0; p++, c = *p) {
                for (checkPtr = trimChars; *checkPtr != c; checkPtr++) {
                    if (*checkPtr == 0) {
                        goto doneLeft;
                    }
                }
            }
        }
        doneLeft:
        Tcl_SetResult(interp, p, TCL_VOLATILE);
        if (right) {
            char *donePtr;

            p = interp->result + strlen(interp->result) - 1;
            donePtr = &interp->result[-1];
            for (c = *p; p != donePtr; p--, c = *p) {
                for (checkPtr = trimChars; *checkPtr != c; checkPtr++) {
                    if (*checkPtr == 0) {
                        goto doneRight;
                    }
                }
            }
            doneRight:
            p[1] = 0;
        }
        return TCL_OK;
    } else if ((c == 't') && (strncmp(argv[1], "trimleft", length) == 0)
            && (length > 4)) {
        left = 1;
        argv[1] = "trimleft";
        goto trim;
    } else if ((c == 't') && (strncmp(argv[1], "trimright", length) == 0)
            && (length > 4)) {
        right = 1;
        argv[1] = "trimright";
        goto trim;
    } else {
        Tcl_AppendResult(interp, "bad option \"", argv[1],
                "\": should be compare, first, index, last, length, match, ",
                "range, tolower, toupper, trim, trimleft, or trimright",
                (char *) NULL);
        return TCL_ERROR;
    }
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_TraceCmd --
 *
 *      This procedure is invoked to process the "trace" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_TraceCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    char c;
    int length;

    if (argc < 2) {
        Tcl_AppendResult(interp, "too few args: should be \"",
                argv[0], " option [arg arg ...]\"", (char *) NULL);
        return TCL_ERROR;
    }
    c = argv[1][1];
    length = strlen(argv[1]);
    if ((c == 'a') && (strncmp(argv[1], "variable", length) == 0)
            && (length >= 2)) {
        char *p;
        int flags, length;
        TraceVarInfo *tvarPtr;

        if (argc != 5) {
            Tcl_AppendResult(interp, "wrong # args: should be \"",
                    argv[0], " variable name ops command\"", (char *) NULL);
            return TCL_ERROR;
        }

        flags = 0;
        for (p = argv[3] ; *p != 0; p++) {
            if (*p == 'r') {
                flags |= TCL_TRACE_READS;
            } else if (*p == 'w') {
                flags |= TCL_TRACE_WRITES;
            } else if (*p == 'u') {
                flags |= TCL_TRACE_UNSETS;
            } else {
                goto badOps;
            }
        }
        if (flags == 0) {
            goto badOps;
        }

        length = strlen(argv[4]);
        tvarPtr = (TraceVarInfo *) ckalloc((unsigned)
                (sizeof(TraceVarInfo) - sizeof(tvarPtr->command) + length + 1));
        tvarPtr->flags = flags;
        tvarPtr->length = length;
        flags |= TCL_TRACE_UNSETS;
        strcpy(tvarPtr->command, argv[4]);
        if (Tcl_TraceVar(interp, argv[2], flags, TraceVarProc,
                (ClientData) tvarPtr) != TCL_OK) {
            ckfree((char *) tvarPtr);
            return TCL_ERROR;
        }
    } else if ((c == 'd') && (strncmp(argv[1], "vdelete", length)
            && (length >= 2)) == 0) {
        char *p;
        int flags, length;
        TraceVarInfo *tvarPtr;
        ClientData clientData;

        if (argc != 5) {
            Tcl_AppendResult(interp, "wrong # args: should be \"",
                    argv[0], " vdelete name ops command\"", (char *) NULL);
            return TCL_ERROR;
        }

        flags = 0;
        for (p = argv[3] ; *p != 0; p++) {
            if (*p == 'r') {
                flags |= TCL_TRACE_READS;
            } else if (*p == 'w') {
                flags |= TCL_TRACE_WRITES;
            } else if (*p == 'u') {
                flags |= TCL_TRACE_UNSETS;
            } else {
                goto badOps;
            }
        }
        if (flags == 0) {
            goto badOps;
        }

        /*
         * Search through all of our traces on this variable to
         * see if there's one with the given command.  If so, then
         * delete the first one that matches.
         */

        length = strlen(argv[4]);
        clientData = 0;
        while ((clientData = Tcl_VarTraceInfo(interp, argv[2], 0,
                TraceVarProc, clientData)) != 0) {
            tvarPtr = (TraceVarInfo *) clientData;
            if ((tvarPtr->length == length) && (tvarPtr->flags == flags)
                    && (strncmp(argv[4], tvarPtr->command, length) == 0)) {
                Tcl_UntraceVar(interp, argv[2], flags | TCL_TRACE_UNSETS,
                        TraceVarProc, clientData);
                ckfree((char *) tvarPtr);
                break;
            }
        }
    } else if ((c == 'i') && (strncmp(argv[1], "vinfo", length) == 0)
            && (length >= 2)) {
        ClientData clientData;
        char ops[4], *p;
        char *prefix = "{";

        if (argc != 3) {
            Tcl_AppendResult(interp, "wrong # args: should be \"",
                    argv[0], " vinfo name\"", (char *) NULL);
            return TCL_ERROR;
        }
        clientData = 0;
        while ((clientData = Tcl_VarTraceInfo(interp, argv[2], 0,
                TraceVarProc, clientData)) != 0) {
            TraceVarInfo *tvarPtr = (TraceVarInfo *) clientData;
            p = ops;
            if (tvarPtr->flags & TCL_TRACE_READS) {
                *p = 'r';
                p++;
            }
            if (tvarPtr->flags & TCL_TRACE_WRITES) {
                *p = 'w';
                p++;
            }
            if (tvarPtr->flags & TCL_TRACE_UNSETS) {
                *p = 'u';
                p++;
            }
            *p = '\0';
            Tcl_AppendResult(interp, prefix, (char *) NULL);
            Tcl_AppendElement(interp, ops, 1);
            Tcl_AppendElement(interp, tvarPtr->command, 0);
            Tcl_AppendResult(interp, "}", (char *) NULL);
            prefix = " {";
        }
    } else {
        Tcl_AppendResult(interp, "bad option \"", argv[1],
                "\": should be variable, vdelete, or vinfo",
                (char *) NULL);
        return TCL_ERROR;
    }
    return TCL_OK;

    badOps:
    Tcl_AppendResult(interp, "bad operations \"", argv[3],
            "\": should be one or more of rwu", (char *) NULL);
    return TCL_ERROR;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * TraceVarProc --
 *
 *      This procedure is called to handle variable accesses that have
 *      been traced using the "trace" command.
 *
 * Results:
 *      Normally returns NULL.  If the trace command returns an error,
 *      then this procedure returns an error string.
 *
 * Side effects:
 *      Depends on the command associated with the trace.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
static char *
TraceVarProc(clientData, interp, name1, name2, flags)
    ClientData clientData;      /* Information about the variable trace. */
    Tcl_Interp *interp;         /* Interpreter containing variable. */
    char *name1;                /* Name of variable or array. */
    char *name2;                /* Name of element within array;  NULL means
                                 * scalar variable is being referenced. */
    int flags;                  /* OR-ed bits giving operation and other
                                 * information. */
{
    TraceVarInfo *tvarPtr = (TraceVarInfo *) clientData;
    char *result;
    int code, cmdLength, flags1, flags2;
    Interp dummy;
#define STATIC_SIZE 199
    char staticSpace[STATIC_SIZE+1];
    char *cmdPtr, *p;

    result = NULL;
    if ((tvarPtr->flags & flags) && !(flags & TCL_INTERP_DESTROYED)) {

        /*
         * Generate a command to execute by appending list elements
         * for the two variable names and the operation.  The five
         * extra characters are for three space, the opcode character,
         * and the terminating null.
         */

        if (name2 == NULL) {
            name2 = "";
        }
        cmdLength = tvarPtr->length + Tcl_ScanElement(name1, &flags1) +
                Tcl_ScanElement(name2, &flags2) + 5;
        if (cmdLength < STATIC_SIZE) {
            cmdPtr = staticSpace;
        } else {
            cmdPtr = (char *) ckalloc((unsigned) cmdLength);
        }
        p = cmdPtr;
        strcpy(p, tvarPtr->command);
        p += tvarPtr->length;
        *p = ' ';
        p++;
        p += Tcl_ConvertElement(name1, p, flags1);
        *p = ' ';
        p++;
        p += Tcl_ConvertElement(name2, p, flags2);
        *p = ' ';
        if (flags & TCL_TRACE_READS) {
            p[1] = 'r';
        } else if (flags & TCL_TRACE_WRITES) {
            p[1] = 'w';
        } else if (flags & TCL_TRACE_UNSETS) {
            p[1] = 'u';
        }
        p[2] = '\0';

        /*
         * Execute the command.  Be careful to save and restore the
         * result from the interpreter used for the command.
         */

        dummy.freeProc = interp->freeProc;
        if (interp->freeProc == 0) {
            Tcl_SetResult((Tcl_Interp *) &dummy, interp->result, TCL_VOLATILE);
        } else {
            dummy.result = interp->result;
        }
        code = Tcl_Eval(interp, cmdPtr, 0, (char **) NULL);
        if (cmdPtr != staticSpace) {
            ckfree(cmdPtr);
        }
        if (code != TCL_OK) {
            result = "access disallowed by trace command";
            Tcl_ResetResult(interp);            /* Must clear error state. */
        }
        Tcl_FreeResult(interp);
        interp->result = dummy.result;
        interp->freeProc = dummy.freeProc;
    }
    if (flags & TCL_TRACE_DESTROYED) {
        ckfree((char *) tvarPtr);
    }
    return result;
}
\f
/*
 *----------------------------------------------------------------------
 *
 * Tcl_WhileCmd --
 *
 *      This procedure is invoked to process the "while" Tcl command.
 *      See the user documentation for details on what it does.
 *
 * Results:
 *      A standard Tcl result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *----------------------------------------------------------------------
 */

        /* ARGSUSED */
int
Tcl_WhileCmd(dummy, interp, argc, argv)
    ClientData dummy;                   /* Not used. */
    Tcl_Interp *interp;                 /* Current interpreter. */
    int argc;                           /* Number of arguments. */
    char **argv;                        /* Argument strings. */
{
    int result, value;

    if (argc != 3) {
        Tcl_AppendResult(interp, "wrong # args: should be \"",
                argv[0], " test command\"", (char *) NULL);
        return TCL_ERROR;
    }

    while (1) {
        result = Tcl_ExprBoolean(interp, argv[1], &value);
        if (result != TCL_OK) {
            return result;
        }
        if (!value) {
            break;
        }
        result = Tcl_Eval(interp, argv[2], 0, (char **) NULL);
        if (result == TCL_CONTINUE) {
            result = TCL_OK;
        } else if (result != TCL_OK) {
            if (result == TCL_ERROR) {
                char msg[60];
                sprintf(msg, "\n    (\"while\" body line %d)",
                        interp->errorLine);
                Tcl_AddErrorInfo(interp, msg);
            }
            break;
        }
    }
    if (result == TCL_BREAK) {
        result = TCL_OK;
    }
    if (result == TCL_OK) {
        Tcl_ResetResult(interp);
    }
    return result;
}