Implement support for PCRE regular expressions for all criteria (for_window, commands, assignments)

include/regex.h

@@ -0,0 +1,28 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ */
+#ifndef _REGEX_H
+#define _REGEX_H
+
+/**
+ * Creates a new 'regex' struct containing the given pattern and a PCRE
+ * compiled regular expression. Also, calls pcre_study because this regex will
+ * most likely be used often (like for every new window and on every relevant
+ * property change of existing windows).
+ *
+ * Returns NULL if the pattern could not be compiled into a regular expression
+ * (and ELOGs an appropriate error message).
+ *
+ */
+struct regex *regex_new(const char *pattern);
+
+/**
+ * Checks if the given regular expression matches the given input and returns
+ * true if it does. In either case, it logs the outcome using LOG(), so it will
+ * be visible without any debug loglevel.
+ *
+ */
+bool regex_matches(struct regex *regex, const char *input);
+
+#endif