Beautiful Code

Sup /prog/-riders
In this thread we post beautiful code. They can be from your job, school, whatever.

Here's a recursive regex parser with support for character classes, $ and & anchors, and the . and * metachars.


int matchhere(char* regexp, char* text);
int matchstar(int c, char* regexp, char* text)
{
    do {
        if (matchhere(regexp, text))
            return 1;
    } while (*text != '\0' && (*text++ == c || c == '.'));
    return 0;
}

int matchhere(char* regexp, char* text)
{
    if (regexp[0] == '\0')
        return 1;
    if (regexp[1] == '*')
        return matchstar(regexp[0], regexp+2, text);
    if (regexp[0] == '$' && regexp[1] == '\0')
        return *text == '\0';
    if (*text != '\0' && (regexp[0] == '.' || regexp[0] == *text))
        return matchhere(regexp+1, text+1);
    return 0;
}

int match(char* regexp, char* text)
{
    if (regexp[0] == '^')
        return matchhere(regexp+1, text);
    do {
        if (matchhere(regexp, text))
            return 1;
    } while (*text++ != '\0');
    return 0;
}