["data", "staged"]: support dropping paths

In this way, GLOB constructs can be used more easily. As the dropping
happens early, this can also be used to solve staging conflicts, by
removing that logical path and later add a consolidated artifact to
that path.

3 files changed, 148 insertions, 5 deletions

diff --git a/README.md b/README.md
index 2e5d427..627c300 100644
--- a/README.md
+++ b/README.md
@@ -328,6 +328,7 @@ Stage data to a logical subdirectory.
 | Field | Description |
 | ----- | ----------- |
 | `"stage"` | The logical directory to stage the files to. Individual directory components are joined with `"/"`. |
+| `"drop"` | List of paths to drop from (each of) the `"srcs"` targets before joining and staging. In this way, GLOB constructs can be used is `"srcs"`. |
 | `"srcs"` | The files to be staged |
 | `"deps"` | Targets of with their runfiles should be added as well. Their staging is not changed. |
 
diff --git a/rules/data/EXPRESSIONS b/rules/data/EXPRESSIONS
new file mode 100644
index 0000000..929eaf8
--- /dev/null
+++ b/rules/data/EXPRESSIONS
@@ -0,0 +1,113 @@
+{ "field_artifacts_without":
+  { "doc":
+    [ "Query and merge artifacts from target_field's targets,"
+    , "leaving out the specified logical paths."
+    ]
+  , "vars": ["fieldname", "transition", "exclude"]
+  , "vars_doc":
+    { "fieldname": ["The name of the target_field to query."]
+    , "transition": ["The optional configuration transition for the targets."]
+    , "exclude": ["The logical paths to exclude"]
+    }
+  , "expression":
+    { "type": "disjoint_map_union"
+    , "msg":
+      [ "artifacts"
+      , {"type": "var", "name": "fieldname"}
+      , "must not overlap after dropping paths"
+      , {"type": "var", "name": "exclude"}
+      ]
+    , "$1":
+      { "type": "foreach"
+      , "var": "x"
+      , "range":
+        {"type": "FIELD", "name": {"type": "var", "name": "fieldname"}}
+      , "body":
+        { "type": "map_union"
+        , "$1":
+          { "type": "foreach_map"
+          , "range":
+            { "type": "DEP_ARTIFACTS"
+            , "dep": {"type": "var", "name": "x"}
+            , "transition":
+              { "type": "var"
+              , "name": "transition"
+              , "default": {"type": "empty_map"}
+              }
+            }
+          , "body":
+            { "type": "if"
+            , "cond":
+              { "type": "lookup"
+              , "key": {"type": "var", "name": "_"}
+              , "map": {"type": "var", "name": "exclude"}
+              }
+            , "then": {"type": "empty_map"}
+            , "else":
+              { "type": "singleton_map"
+              , "key": {"type": "var", "name": "_"}
+              , "value": {"type": "var", "name": "$_"}
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+, "field_runfiles_without":
+  { "doc":
+    [ "Query and merge runfiles from target_field's targets,"
+    , "leaving out the specified logical paths."
+    ]
+  , "vars": ["fieldname", "transition", "exclude"]
+  , "vars_doc":
+    { "fieldname": ["The name of the target_field to query."]
+    , "transition": ["The optional configuration transition for the targets."]
+    , "exclude": ["The logical paths to exclude"]
+    }
+  , "expression":
+    { "type": "disjoint_map_union"
+    , "msg":
+      [ "artifacts"
+      , {"type": "var", "name": "fieldname"}
+      , "must not overlap after dropping paths"
+      , {"type": "var", "name": "exclude"}
+      ]
+    , "$1":
+      { "type": "foreach"
+      , "var": "x"
+      , "range":
+        {"type": "FIELD", "name": {"type": "var", "name": "fieldname"}}
+      , "body":
+        { "type": "map_union"
+        , "$1":
+          { "type": "foreach_map"
+          , "range":
+            { "type": "DEP_RUNFILES"
+            , "dep": {"type": "var", "name": "x"}
+            , "transition":
+              { "type": "var"
+              , "name": "transition"
+              , "default": {"type": "empty_map"}
+              }
+            }
+          , "body":
+            { "type": "if"
+            , "cond":
+              { "type": "lookup"
+              , "key": {"type": "var", "name": "_"}
+              , "map": {"type": "var", "name": "exclude"}
+              }
+            , "then": {"type": "empty_map"}
+            , "else":
+              { "type": "singleton_map"
+              , "key": {"type": "var", "name": "_"}
+              , "value": {"type": "var", "name": "$_"}
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/rules/data/RULES b/rules/data/RULES
index feb1a73..d1f8975 100644
--- a/rules/data/RULES
+++ b/rules/data/RULES
@@ -1,7 +1,7 @@
 { "staged":
   { "doc": ["Stage data to a logical subdirectory."]
   , "target_fields": ["srcs", "deps"]
-  , "string_fields": ["stage"]
+  , "string_fields": ["stage", "drop"]
   , "field_doc":
     { "srcs": ["The files to be staged"]
     , "stage":
@@ -12,9 +12,15 @@
       [ "Targets of with their runfiles should be added as well."
       , "Their staging is not changed."
       ]
+    , "drop":
+      [ "List of paths to drop from (each of) the \"srcs\" targets"
+      , "before joining and staging. In this way, GLOB constructs can"
+      , "be used is \"srcs\"."
+      ]
     }
   , "artifacts_doc":
-    [ "The runfiles of the \"srcs\" targets staged to the directory"
+    [ "The runfiles and artifacts of the \"srcs\" targets, leaving out"
+    , "the ones with logical path in \"drop\", staged to the directory"
     , "specified in \"stage\" together the runfiles of the targets"
     , "specied in the field \"deps\" (in their original location)."
     ]
@@ -22,6 +28,8 @@
   , "imports":
     { "runfiles": ["./", "..", "field_runfiles"]
     , "artifacts": ["./", "..", "field_artifacts"]
+    , "runfiles w/o": "field_artifacts_without"
+    , "artifacts w/o": "field_artifacts_without"
     }
   , "expression":
     { "type": "let*"
@@ -32,15 +40,36 @@
           , "$1": {"type": "FIELD", "name": "stage"}
           }
         ]
+      , [ "exclude"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "foreach"
+            , "range": {"type": "FIELD", "name": "drop"}
+            , "body":
+              { "type": "singleton_map"
+              , "key": {"type": "var", "name": "_"}
+              , "value": true
+              }
+            }
+          }
+        ]
       , [ "srcs"
         , { "type": "let*"
           , "bindings": [["fieldname", "srcs"]]
           , "body":
             { "type": "map_union"
             , "$1":
-              [ {"type": "CALL_EXPRESSION", "name": "runfiles"}
-              , {"type": "CALL_EXPRESSION", "name": "artifacts"}
-              ]
+              { "type": "if"
+              , "cond": {"type": "var", "name": "exclude"}
+              , "then":
+                [ {"type": "CALL_EXPRESSION", "name": "runfiles w/o"}
+                , {"type": "CALL_EXPRESSION", "name": "artifacts w/o"}
+                ]
+              , "else":
+                [ {"type": "CALL_EXPRESSION", "name": "runfiles"}
+                , {"type": "CALL_EXPRESSION", "name": "artifacts"}
+                ]
+              }
             }
           }
         ]