Add regex utility functions

1 files changed, 57 insertions, 0 deletions

diff --git a/libbutl/regex.hxx b/libbutl/regex.hxx
new file mode 100644
index 0000000..4a93106
--- /dev/null
+++ b/libbutl/regex.hxx
@@ -0,0 +1,57 @@
+// file      : libbutl/regex.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUTL_REGEX_HXX
+#define LIBBUTL_REGEX_HXX
+
+#include <regex>
+#include <iosfwd>
+#include <string>  // basic_string
+#include <utility> // pair
+
+#include <libbutl/export.hxx>
+
+namespace butl
+{
+  // Like std::regex_match() but extends the standard ECMA-262
+  // substitution escape sequences with a subset of Perl sequences:
+  //
+  // \\, \u, \l, \U, \L, \E, \1, ..., \9
+  //
+  // Also return the resulting string as well as whether the search
+  // succeeded.
+  //
+  // Notes and limitations:
+  //
+  // - The only valid regex_constants flags are match_default,
+  //   format_first_only (format_no_copy can easily be supported).
+  //
+  // - If backslash doesn't start any of the listed sequences then it is
+  //   silently dropped and the following character is copied as is.
+  //
+  // - The character case conversion is performed according to the global
+  //   C++ locale (which is, unless changed, is the same as C locale and
+  //   both default to the POSIX locale aka "C").
+  //
+  template <typename C>
+  std::pair<std::basic_string<C>, bool>
+  regex_replace_ex (const std::basic_string<C>&,
+                    const std::basic_regex<C>&,
+                    const std::basic_string<C>& fmt,
+                    std::regex_constants::match_flag_type =
+                      std::regex_constants::match_default);
+}
+
+namespace std
+{
+  // Print regex error description but only if it is meaningful (this is also
+  // why we have to print leading colon).
+  //
+  LIBBUTL_EXPORT ostream&
+  operator<< (ostream&, const regex_error&);
+}
+
+#include <libbutl/regex.txx>
+
+#endif // LIBBUTL_REGEX_HXX