C

Regular Expression Replace Full Matches

See more Regular Expressions Examples

Demonstrates replacing the full matches of a regular expression.

Note: Chilkat uses PCRE2. See PCRE2 Regular Expressions
Also see: PCRE2 Performance

C

#include <C_CkStringBuilder.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    const char *subject;
    const char *pattern;
    HCkStringBuilder sb;
    HCkJsonObject json;
    int timeoutMs;
    int numMatches;
    HCkStringBuilder sbTemp;
    int i;

    success = FALSE;

    success = FALSE;

    subject = "John Anders, +_+_+ Mary Robins $$$$";
    pattern = "\\w+\\s+\\w+";

    sb = CkStringBuilder_Create();
    CkStringBuilder_Append(sb,subject);

    json = CkJsonObject_Create();
    CkJsonObject_putEmitCompact(json,FALSE);

    timeoutMs = 2000;
    numMatches = CkStringBuilder_RegexMatch(sb,pattern,json,timeoutMs);
    if (numMatches < 0) {
        // Probably an error in the regular expression.
        // Suggestion: Use AI to help create and/or diagnose regular expressions.
        printf("%s\n",CkStringBuilder_lastErrorText(sb));
        CkStringBuilder_Dispose(sb);
        CkJsonObject_Dispose(json);
        return;
    }

    // Examine the matches:
    printf("%s\n",CkJsonObject_emit(json));

    // {
    //   "match": [
    //     {
    //       "group": [
    //         {
    //           "cap": "John Anders",
    //           "idx": 0,
    //           "len": 11
    //         }
    //       ]
    //     },
    //     {
    //       "group": [
    //         {
    //           "cap": "Mary Robins",
    //           "idx": 19,
    //           "len": 11
    //         }
    //       ]
    //     }
    //   ]
    // }

    sbTemp = CkStringBuilder_Create();

    i = 0;
    numMatches = CkJsonObject_SizeOfArray(json,"match");
    while (i < numMatches) {

        CkJsonObject_putI(json,i);

        // The full match is always in group 0.
        CkStringBuilder_Clear(sbTemp);
        CkJsonObject_StringOfSb(json,"match[i].group[0].cap",sbTemp);

        // Indicate that we wish to replace the full match with it's value converted to uppercase.
        CkStringBuilder_ToUppercase(sbTemp);
        CkJsonObject_UpdateSb(json,"match[i].group[0].rep",sbTemp);

        i = i + 1;
    }

    // The JSON now has replacement strings:
    printf("%s\n",CkJsonObject_emit(json));

    // {
    //   "match": [
    //     {
    //       "group": [
    //         {
    //           "cap": "John Anders",
    //           "idx": 0,
    //           "len": 11,
    //           "rep": "JOHN ANDERS"
    //         }
    //       ]
    //     },
    //     {
    //       "group": [
    //         {
    //           "cap": "Mary Robins",
    //           "idx": 19,
    //           "len": 11,
    //           "rep": "MARY ROBINS"
    //         }
    //       ]
    //     }
    //   ]
    // }

    // Call RegexReplace to update the StringBuilder with the replacements.
    success = CkStringBuilder_RegexReplace(sb,json);
    if (success == FALSE) {
        printf("%s\n",CkStringBuilder_lastErrorText(sb));
        CkStringBuilder_Dispose(sb);
        CkJsonObject_Dispose(json);
        CkStringBuilder_Dispose(sbTemp);
        return;
    }

    printf("Result after doing replacements:\n");
    printf("%s\n",CkStringBuilder_getAsString(sb));

    // Result after doing replacements:
    // JOHN ANDERS, +_+_+ MARY ROBINS $$$$


    CkStringBuilder_Dispose(sb);
    CkJsonObject_Dispose(json);
    CkStringBuilder_Dispose(sbTemp);

    }