rules: Propagate PATH list from defaults

... instead of creating an ENV from it and propagating this.
The idea is to keep PATH entries separate and only join them
with ":" when we need it. In this way, we can accumulate
PATHs from multiple defaults later, and perform a
deduplication ("nub_left") to shorten the final string
length.

1 files changed, 20 insertions, 15 deletions

diff --git a/CC/RULES b/CC/RULES
index 8af70be..33b8520 100644
--- a/CC/RULES
+++ b/CC/RULES
@@ -66,7 +66,7 @@
       ]
     , "PATH":
       [ "Path for looking up the compilers. Individual paths are joined"
-      , "with \":\"."
+      , "with \":\". Specifying this field extends values from \"base\"."
       ]
     }
   , "config_vars": ["ARCH", "HOST_ARCH"]
@@ -74,6 +74,7 @@
     { "base-provides": "defaults-base-provides"
     , "base-provides-list": "defaults-base-provides-list"
     , "artifacts_list": ["./", "..", "field_artifacts_list"]
+    , "nub_left": ["", "nub_left"]
     , "compile-deps": "compile-deps"
     , "compile-args-deps": "compile-args-deps"
     , "link-deps": "link-deps"
@@ -142,23 +143,26 @@
           , "else": {"type": "CALL_EXPRESSION", "name": "base-provides"}
           }
         ]
-      , ["provider", "ENV"]
-      , ["default", {"type": "empty_map"}]
-      , [ "ENV"
-        , { "type": "if"
-          , "cond": {"type": "var", "name": "PATH"}
-          , "then":
-            { "type": "singleton_map"
-            , "key": "PATH"
-            , "value":
-              { "type": "join"
-              , "separator": ":"
-              , "$1": {"type": "var", "name": "PATH"}
+      , ["provider", "PATH"]
+      , [ "PATH"
+        , { "type": "++"
+          , "$1":
+            [ {"type": "var", "name": "PATH"}
+            , { "type": "++"
+              , "$1": {"type": "CALL_EXPRESSION", "name": "base-provides-list"}
               }
-            }
-          , "else": {"type": "CALL_EXPRESSION", "name": "base-provides"}
+            ]
+          }
+        ]
+      , [ "PATH"
+        , { "type": "let*"
+          , "bindings": [["list", {"type": "var", "name": "PATH"}]]
+          , "body": {"type": "CALL_EXPRESSION", "name": "nub_left"}
           }
         ]
+      , ["provider", "ENV"]
+      , ["default", {"type": "empty_map"}]
+      , ["ENV", {"type": "CALL_EXPRESSION", "name": "base-provides"}]
       , ["provider", "NON_SYSTEM_TOOLS"]
       , ["default", {"type": "empty_map"}]
       , [ "NON_SYSTEM_TOOLS"
@@ -299,6 +303,7 @@
           , "CXXFLAGS"
           , "LDFLAGS"
           , "AR"
+          , "PATH"
           , "ENV"
           , "TOOLCHAIN"
           , "NON_SYSTEM_TOOLS"