With my growing constexpr fascination, I thought of using it for something that would be really hard using template meta-programs. How about implementing a compile-time regular expression matcher? Fortunately, a simple regular expression matcher has already been written by Rob Pike . I just rewrote it using constexpr: single return statement in functions, no modifications to the parameters, abundant ternery operators, and recursion. Here we go... constexpr int match_c(const char *regexp, const char *text); constexpr int matchhere_c(const char *regexp, const char *text); constexpr int matchstar_c(int c, const char *regexp, const char *text); constexpr int matchend_c(const char * regexp, const char * text); constexpr int matchend_c(const char * regexp, const char * text) { return matchhere_c(regexp, text) ? 1 : (*text == '\0') ? 0 : matchend_c(regexp, text+1); } constexpr int match_c(const char *regexp, const char *text) { return (regexp[0] == '^') ? matchher
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