Add support for regex function family

4 files changed, 335 insertions, 1 deletions

diff --git a/build2/buildfile b/build2/buildfile
index 8525eb8..d2aa7c1 100644
--- a/build2/buildfile
+++ b/build2/buildfile
@@ -19,6 +19,7 @@ exe{b}:                                                   \
             {            cxx}{ functions-filesystem     } \
             {            cxx}{ functions-path           } \
             {            cxx}{ functions-process-path   } \
+            {            cxx}{ functions-regex          } \
             {            cxx}{ functions-string         } \
             {            cxx}{ functions-target-triplet } \
             {hxx         cxx}{ lexer                    } \
diff --git a/build2/function.cxx b/build2/function.cxx
index 399d679..f7de749 100644
--- a/build2/function.cxx
+++ b/build2/function.cxx
@@ -304,6 +304,7 @@ namespace build2
   void filesystem_functions ();     // functions-filesystem.cxx
   void path_functions ();           // functions-path.cxx
   void process_path_functions ();   // functions-process-path.cxx
+  void regex_functions ();          // functions-regex.cxx
   void string_functions ();         // functions-string.cxx
   void target_triplet_functions (); // functions-target-triplet.cxx
 
@@ -315,6 +316,7 @@ namespace build2
       filesystem_functions ();
       path_functions ();
       process_path_functions ();
+      regex_functions ();
       string_functions ();
       target_triplet_functions ();
     }
diff --git a/build2/functions-regex.cxx b/build2/functions-regex.cxx
new file mode 100644
index 0000000..bdecc14
--- /dev/null
+++ b/build2/functions-regex.cxx
@@ -0,0 +1,331 @@
+// file      : build2/functions-regex.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <sstream>
+
+#include <libbutl/regex.hxx>
+
+#include <build2/function.hxx>
+#include <build2/variable.hxx>
+
+using namespace std;
+using namespace butl;
+
+namespace build2
+{
+  // Convert value of an arbitrary type to string.
+  //
+  static inline string
+  to_string (value&& v)
+  {
+    // Optimize for the string value type.
+    //
+    if (v.type != &value_traits<string>::value_type)
+      untypify (v);
+
+    return convert<string> (move (v));
+  }
+
+  // Parse a regular expression. Throw invalid_argument if it is not valid.
+  //
+  static regex
+  parse_regex (const string& s, regex::flag_type f)
+  {
+    try
+    {
+      return regex (s, f);
+    }
+    catch (const regex_error& e)
+    {
+      // Print regex_error description if meaningful (no space).
+      //
+      ostringstream os;
+      os << "invalid regex '" << s << "'" << e;
+      throw invalid_argument (os.str ());
+    }
+  }
+
+  // Match value of an arbitrary type against the regular expression. See
+  // match() overloads (below) for details.
+  //
+  static value
+  match (value&& v, const string& re, optional<names>&& flags)
+  {
+    // Parse flags.
+    //
+    regex::flag_type rf (regex::ECMAScript);
+    bool subs (false);
+
+    if (flags)
+    {
+      for (auto& f: *flags)
+      {
+        string s (convert<string> (move (f)));
+
+        if (s == "icase")
+          rf |= regex::icase;
+        else if (s == "return_subs")
+          subs = true;
+        else
+          throw invalid_argument ("invalid flag '" + s + "'");
+      }
+    }
+
+    // Parse regex.
+    //
+    regex rge (parse_regex (re, rf));
+
+    // Match.
+    //
+    string s (to_string (move (v)));
+
+    if (!subs)
+      return value (regex_match (s, rge)); // Return boolean value.
+
+    names r;
+    match_results<string::const_iterator> m;
+
+    if (regex_match (s, m, rge))
+    {
+      assert (!m.empty ());
+
+      for (size_t i (1); i != m.size (); ++i)
+      {
+        if (m[i].matched)
+          r.emplace_back (m.str (i));
+      }
+    }
+
+    return value (r);
+  }
+
+  // Determine if there is a match between the regular expression and some
+  // part of a value of an arbitrary type. See search() overloads (below)
+  // for details.
+  //
+  static value
+  search (value&& v, const string& re, optional<names>&& flags)
+  {
+    // Parse flags.
+    //
+    regex::flag_type rf (regex::ECMAScript);
+    bool match (false);
+    bool subs (false);
+
+    if (flags)
+    {
+      for (auto& f: *flags)
+      {
+        string s (convert<string> (move (f)));
+
+        if (s == "icase")
+          rf |= regex::icase;
+        else if (s == "return_match")
+          match = true;
+        else if (s == "return_subs")
+          subs = true;
+        else
+          throw invalid_argument ("invalid flag '" + s + "'");
+      }
+    }
+
+    // Parse regex.
+    //
+    regex rge (parse_regex (re, rf));
+
+    // Search.
+    //
+    string s (to_string (move (v)));
+
+    if (!match && !subs)
+      return value (regex_search (s, rge)); // Return boolean value.
+
+    names r;
+    match_results<string::const_iterator> m;
+
+    if (regex_search (s, m, rge))
+    {
+      assert (!m.empty ());
+
+      if (match)
+      {
+        assert (m[0].matched);
+        r.emplace_back (m.str (0));
+      }
+
+      if (subs)
+      {
+        for (size_t i (1); i != m.size (); ++i)
+        {
+          if (m[i].matched)
+            r.emplace_back (m.str (i));
+        }
+      }
+    }
+
+    return value (r);
+  }
+
+  // Replace matched parts in a value of an arbitrary type, using the format
+  // string. See replace() overloads (below) for details.
+  //
+  static names
+  replace (value&& v,
+           const string& re,
+           const string& fmt,
+           optional<names>&& flags)
+  {
+    // Parse flags.
+    //
+    regex::flag_type rf (regex::ECMAScript);
+    regex_constants::match_flag_type mf (regex_constants::match_default);
+
+    if (flags)
+    {
+      for (auto& f: *flags)
+      {
+        string s (convert<string> (move (f)));
+
+        if (s == "icase")
+          rf |= regex::icase;
+        else if (s == "format_first_only")
+          mf |= regex_constants::format_first_only;
+        else if (s == "format_no_copy")
+          mf |= regex_constants::format_no_copy;
+        else
+          throw invalid_argument ("invalid flag '" + s + "'");
+      }
+    }
+
+    // Parse regex.
+    //
+    regex rge (parse_regex (re, rf));
+
+    // Replace.
+    //
+    names r;
+
+    try
+    {
+      string s (to_string (move (v)));
+      r.emplace_back (regex_replace_ex (s, rge, fmt, mf).first);
+    }
+    catch (const regex_error& e)
+    {
+      fail << "unable to replace" << e;
+    }
+
+    return r;
+  }
+
+  void
+  regex_functions ()
+  {
+    function_family f ("regex");
+
+    // match
+    //
+    // Match a value of an arbitrary type against the regular expression.
+    // Convert the value to string prior to matching. Return the boolean value
+    // unless return_subs flag is specified (see below), in which case return
+    // names (empty if no match).
+    //
+    // The following flags are supported:
+    //
+    // icase       - match ignoring case
+    //
+    // return_subs - return names (rather than boolean), that contain
+    //               sub-strings that match the marked sub-expressions
+    //
+    f[".match"] = [](value s, string re, optional<names> flags)
+    {
+      return match (move (s), re, move (flags));
+    };
+
+    f[".match"] = [](value s, names re, optional<names> flags)
+    {
+      return match (move (s), convert<string> (move (re)), move (flags));
+    };
+
+    // search
+    //
+    // Determine if there is a match between the regular expression and some
+    // part of a value of an arbitrary type. Convert the value to string prior
+    // to searching. Return the boolean value unless return_match or
+    // return_subs flag is specified (see below) in which case return names
+    // (empty if no match).
+    //
+    // The following flags are supported:
+    //
+    // icase        - match ignoring case
+    //
+    // return_match - return names (rather than boolean), that contain a
+    //                sub-string that matches the whole regular expression
+    //
+    // return_subs -  return names (rather than boolean), that contain
+    //                sub-strings that match the marked sub-expressions
+    //
+    // If both return_match and return_subs flags are specified then the
+    // sub-string that matches the whole regular expression comes first.
+    //
+    f[".search"] = [](value s, string re, optional<names> flags)
+    {
+      return search (move (s), re, move (flags));
+    };
+
+    f[".search"] = [](value s, names re, optional<names> flags)
+    {
+      return search (move (s), convert<string> (move (re)), move (flags));
+    };
+
+    // replace
+    //
+    // Replace matched parts in a value of an arbitrary type, using the format
+    // string. Convert the value to string prior to matching. The result value
+    // is always untyped, regardless of the argument type.
+    //
+    // Substitution escape sequences are extended with a subset of Perl
+    // sequences (see regex_replace_ex() for details).
+    //
+    // The following flags are supported:
+    //
+    // icase             - match ignoring case
+    //
+    // format_first_only - only replace the first match
+    //
+    // format_no_copy    - do not copy unmatched value parts to the result
+    //
+    // If both format_first_only and format_no_copy flags are specified then
+    // all the result will contain is the replacement of the first match.
+    //
+    f[".replace"] = [](value s, string re, string fmt, optional<names> flags)
+    {
+      return replace (move (s), re, fmt, move (flags));
+    };
+
+    f[".replace"] = [](value s, string re, names fmt, optional<names> flags)
+    {
+      return replace (move (s),
+                      re,
+                      convert<string> (move (fmt)),
+                      move (flags));
+    };
+
+    f[".replace"] = [](value s, names re, string fmt, optional<names> flags)
+    {
+      return replace (move (s),
+                      convert<string> (move (re)),
+                      fmt,
+                      move (flags));
+    };
+
+    f[".replace"] = [](value s, names re, names fmt, optional<names> flags)
+    {
+      return replace (move (s),
+                      convert<string> (move (re)),
+                      convert<string> (move (fmt)),
+                      move (flags));
+    };
+  }
+}
diff --git a/build2/variable.hxx b/build2/variable.hxx
index 19a6c69..f0218fe 100644
--- a/build2/variable.hxx
+++ b/build2/variable.hxx
@@ -263,7 +263,7 @@ namespace build2
   bool operator>= (const value&, const value&);
 
   // Value cast. The first three expect the value to be not NULL. The cast
-  // from lookup expects the value to aslo be defined.
+  // from lookup expects the value to also be defined.
   //
   // Note that a cast to names expects the value to be untyped while a cast
   // to vector<names> -- typed.