regexpr.h

This file exports functions for performing regular expression operations on C++ strings. It will be unnecessary once the C++11 regex library is widely available, but as of this writing the regex library is not supported on gcc and some other major C++ compilers.

Here is a short example usage of the functions in this library: 

string s = "aaaaaab";
if (regexMatch(s, "a*b")) {
    s = regexReplace(s, "a{3}b", "X");   // returns "aaaX"
}
...

The regular expression functions here are implemented by sending the strings and regexes to the Java Back-End to run the operations in Java. This is a bit kludgy but we don't want to write our own regex parser from scratch. Using Java's is a compromise for now. Note that the performance of this implementation is slow and should not be relied upon in tight loops or performance-critical code.

The syntax of regular expressions accepted is the same as that accepted by Java's java.util.regex.Pattern class and as described at the following URL:

Available since: 2014/03/01 version of C++ library

Functions
regexMatch(s, regexp) Returns true if the given string matches the given regular expression as a substring.
regexMatchCount(s, regexp) Returns the number of times the given regular expression is found inside the given string.
regexReplace(s, regexp, replacement) Replaces all occurrences of the given regular expression in the given string with the given replacement text, and returns the resulting string.

Function detail

bool regexMatch(string s, string regexp);
Returns true if the given string matches the given regular expression as a substring. If the regular expression is not matched, returns false.

Usage:

if (regexMatch(s, regexp)) {
    ...
}

int regexMatchCount(string s, string regexp);
Returns the number of times the given regular expression is found inside the given string. Returns 0 if there are no matches for the regular expression.

Usage:

int count = regexMatchCount(s, regexp);

string regexReplace(string s, string regexp, string replacement);
Replaces all occurrences of the given regular expression in the given string with the given replacement text, and returns the resulting string.

Usage:

s = regexReplace(s, regexp, replacement);