From e2445d5d031b9489215cbac4f39db56cd40270df Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 2 Jun 2020 08:06:31 +0200
Subject: Add $target.process_path() analogous to $target.path()

---
 libbuild2/functions-name.cxx | 30 +++++++++++++++++++++++++++++-
 libbuild2/target.cxx         |  2 +-
 libbuild2/target.hxx         |  4 +++-
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/libbuild2/functions-name.cxx b/libbuild2/functions-name.cxx
index 70659ee..ca0f8ce 100644
--- a/libbuild2/functions-name.cxx
+++ b/libbuild2/functions-name.cxx
@@ -114,7 +114,7 @@ namespace build2
     fn["path"] = [](const scope* s, names ns)
     {
       if (s == nullptr)
-        fail << "target.path() called out of scope" << endf;
+        fail << "target.path() called out of scope";
 
       // Most of the time we will have a single target so optimize for that.
       //
@@ -150,6 +150,34 @@ namespace build2
                            make_move_iterator (r.end ())));
     };
 
+    // This one can only be called on a single target since we don't support
+    // containers of process_path's (though we probably could).
+    //
+    fn["process_path"] = [](const scope* s, names ns)
+    {
+      if (s == nullptr)
+        fail << "target.process_path() called out of scope";
+
+      if (ns.empty () || ns.size () != (ns[0].pair ? 2 : 1))
+        fail << "target.process_path() expects single target";
+
+      name o;
+      const target& t (
+        to_target (*s, move (ns[0]), move (ns[0].pair ? ns[1] : o)));
+
+      if (const auto* et = t.is_a<exe> ())
+      {
+        process_path r (et->process_path ());
+
+        if (r.empty ())
+          fail << "target " << t << " path is not assigned";
+
+        return r;
+      }
+      else
+        fail << "target " << t << " is not process_path-based" << endf;
+    };
+
     // Name-specific overloads from builtins.
     //
     function_family fb (m, "builtin");
diff --git a/libbuild2/target.cxx b/libbuild2/target.cxx
index b9cfea7..b65a4fa 100644
--- a/libbuild2/target.cxx
+++ b/libbuild2/target.cxx
@@ -1073,7 +1073,7 @@ namespace build2
                         bool search)
   {
     // If we are searching for an executable that is not a target, then use
-    // the build machine executable extension. Otherwise, if this is a target,
+    // the host machine executable extension. Otherwise, if this is a target,
     // then we expect the rule to supply the target machine extension. But if
     // it doesn't, then fallback to no extension (e.g., a script).
     //
diff --git a/libbuild2/target.hxx b/libbuild2/target.hxx
index 72b7acc..9a4aed5 100644
--- a/libbuild2/target.hxx
+++ b/libbuild2/target.hxx
@@ -1684,7 +1684,9 @@ namespace build2
     virtual const target_type& dynamic_type () const {return static_type;}
   };
 
-  // Executable file.
+  // Executable file (not necessarily binary, though we do fallback to the
+  // host machine executable extension in certain cases; see the default
+  // extension derivation for details).
   //
   class LIBBUILD2_SYMEXPORT exe: public file
   {
-- 
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