Add support for rule hints

A rule hint is a target attribute, for example:

[rule_hint=cxx] exe{hello}: c{hello}

Rule hints can be used to resolve ambiguity when multiple rules match the same
target as well as to override an unambiguous match.

4 files changed, 14 insertions, 12 deletions

diff --git a/libbuild2/bash/init.cxx b/libbuild2/bash/init.cxx
index a1effa1..88c88ba 100644
--- a/libbuild2/bash/init.cxx
+++ b/libbuild2/bash/init.cxx
@@ -20,7 +20,7 @@ namespace build2
   namespace bash
   {
     static const in_rule in_rule_;
-    static const install_rule install_rule_ (in_rule_);
+    static const install_rule install_rule_ (in_rule_, "bash.in");
 
     bool
     init (scope& rs,
@@ -71,11 +71,11 @@ namespace build2
 
       if (install_loaded)
       {
-        bs.insert_rule<exe>  (perform_install_id,   "bash.install",   install_rule_);
-        bs.insert_rule<exe>  (perform_uninstall_id, "bash.uninstall", install_rule_);
+        bs.insert_rule<exe>  (perform_install_id,   "bash.install", install_rule_);
+        bs.insert_rule<exe>  (perform_uninstall_id, "bash.install", install_rule_);
 
-        bs.insert_rule<bash> (perform_install_id,   "bash.install",   install_rule_);
-        bs.insert_rule<bash> (perform_uninstall_id, "bash.uninstall", install_rule_);
+        bs.insert_rule<bash> (perform_install_id,   "bash.install", install_rule_);
+        bs.insert_rule<bash> (perform_uninstall_id, "bash.install", install_rule_);
       }
 
       return true;
diff --git a/libbuild2/bash/rule.cxx b/libbuild2/bash/rule.cxx
index ec24226..3048d3c 100644
--- a/libbuild2/bash/rule.cxx
+++ b/libbuild2/bash/rule.cxx
@@ -41,7 +41,7 @@ namespace build2
     // in_rule
     //
     bool in_rule::
-    match (action a, target& t, const string&) const
+    match (action a, target& t) const
     {
       tracer trace ("bash::in_rule::match");
 
@@ -424,12 +424,13 @@ namespace build2
     // install_rule
     //
     bool install_rule::
-    match (action a, target& t, const string& hint) const
+    match (action a, target& t) const
     {
       // We only want to handle installation if we are also the ones building
       // this target. So first run in's match().
       //
-      return in_.match (a, t, hint) && file_rule::match (a, t, "");
+      return in_.sub_match (in_name_, update_id, a, t) &&
+        file_rule::match (a, t);
     }
 
     recipe install_rule::
diff --git a/libbuild2/bash/rule.hxx b/libbuild2/bash/rule.hxx
index f69ac3b..1a0cb36 100644
--- a/libbuild2/bash/rule.hxx
+++ b/libbuild2/bash/rule.hxx
@@ -32,7 +32,7 @@ namespace build2
       in_rule (): rule ("bash.in 1", "bash.in", '@', false /* strict */) {}
 
       virtual bool
-      match (action, target&, const string&) const override;
+      match (action, target&) const override;
 
       virtual recipe
       apply (action, target&) const override;
@@ -68,16 +68,17 @@ namespace build2
     class LIBBUILD2_BASH_SYMEXPORT install_rule: public install::file_rule
     {
     public:
-      install_rule (const in_rule& in): in_ (in) {}
+      install_rule (const in_rule& r, const char* n): in_ (r), in_name_ (n) {}
 
       virtual bool
-      match (action, target&, const string&) const override;
+      match (action, target&) const override;
 
       virtual recipe
       apply (action, target&) const override;
 
     protected:
       const in_rule& in_;
+      const string in_name_;
     };
   }
 }
diff --git a/libbuild2/bash/target.cxx b/libbuild2/bash/target.cxx
index 6fa7cf4..5240fed 100644
--- a/libbuild2/bash/target.cxx
+++ b/libbuild2/bash/target.cxx
@@ -23,7 +23,7 @@ namespace build2
       &target_pattern_var<bash_ext_def>,
       nullptr,
       &file_search,
-      false
+      target_type::flag::none
     };
   }
 }