Initial self-hosting commit

This is the initial version of our tool that is able to
build itself. In can be bootstrapped by

  ./bin/bootstrap.py

Co-authored-by: Oliver Reiche <oliver.reiche@huawei.com>
Co-authored-by: Victor Moreno <victor.moreno1@huawei.com>

10 files changed, 1965 insertions, 0 deletions

diff --git a/CC/EXPRESSIONS b/CC/EXPRESSIONS
new file mode 100644
index 0000000..f1e6592
--- /dev/null
+++ b/CC/EXPRESSIONS
@@ -0,0 +1,504 @@
+{ "default-CC":
+  { "expression":
+    { "type": "join"
+    , "$1":
+      { "type": "++"
+      , "$1":
+        { "type": "foreach"
+        , "var": "x"
+        , "range": {"type": "FIELD", "name": "defaults"}
+        , "body":
+          { "type": "DEP_PROVIDES"
+          , "provider": "CC"
+          , "dep": {"type": "var", "name": "x"}
+          }
+        }
+      }
+    }
+  }
+, "default-CXX":
+  { "expression":
+    { "type": "join"
+    , "$1":
+      { "type": "++"
+      , "$1":
+        { "type": "foreach"
+        , "var": "x"
+        , "range": {"type": "FIELD", "name": "defaults"}
+        , "body":
+          { "type": "DEP_PROVIDES"
+          , "provider": "CXX"
+          , "dep": {"type": "var", "name": "x"}
+          }
+        }
+      }
+    }
+  }
+, "default-CFLAGS":
+  { "expression":
+    { "type": "++"
+    , "$1":
+      { "type": "foreach"
+      , "var": "x"
+      , "range": {"type": "FIELD", "name": "defaults"}
+      , "body":
+        { "type": "DEP_PROVIDES"
+        , "provider": "CFLAGS"
+        , "dep": {"type": "var", "name": "x"}
+        }
+      }
+    }
+  }
+, "default-CXXFLAGS":
+  { "expression":
+    { "type": "++"
+    , "$1":
+      { "type": "foreach"
+      , "var": "x"
+      , "range": {"type": "FIELD", "name": "defaults"}
+      , "body":
+        { "type": "DEP_PROVIDES"
+        , "provider": "CXXFLAGS"
+        , "dep": {"type": "var", "name": "x"}
+        }
+      }
+    }
+  }
+, "default-ENV":
+  { "expression":
+    { "type": "foreach"
+    , "var": "x"
+    , "range": {"type": "FIELD", "name": "defaults"}
+    , "body":
+      { "type": "DEP_PROVIDES"
+      , "provider": "ENV"
+      , "dep": {"type": "var", "name": "x"}
+      }
+    }
+  }
+, "configure transition":
+  { "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "OS"
+        , { "type": "assert_non_empty"
+          , "msg": "Missing field \"os\" for \"configure\"."
+          , "$1": {"type": "join", "$1": {"type": "FIELD", "name": "os"}}
+          }
+        ]
+      , [ "ARCH"
+        , { "type": "assert_non_empty"
+          , "msg": "Missing field \"arch\" for \"configure\"."
+          , "$1": {"type": "join", "$1": {"type": "FIELD", "name": "arch"}}
+          }
+        ]
+      , ["HOST_ARCH", {"type": "var", "name": "ARCH"}]
+      , [ "TARGET_ARCH"
+        , {"type": "join", "$1": {"type": "FIELD", "name": "target_arch"}}
+        ]
+      , [ "TARGET_ARCH"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "TARGET_ARCH"}
+          , "then": {"type": "var", "name": "TARGET_ARCH"}
+          , "else": {"type": "var", "name": "ARCH"}
+          }
+        ]
+      ]
+    , "body":
+      { "type": "map_union"
+      , "$1":
+        [ { "type": "singleton_map"
+          , "key": "OS"
+          , "value": {"type": "var", "name": "OS"}
+          }
+        , { "type": "singleton_map"
+          , "key": "ARCH"
+          , "value": {"type": "var", "name": "TARGET_ARCH"}
+          }
+        , { "type": "singleton_map"
+          , "key": "HOST_ARCH"
+          , "value": {"type": "var", "name": "HOST_ARCH"}
+          }
+        , { "type": "singleton_map"
+          , "key": "TARGET_ARCH"
+          , "value": {"type": "var", "name": "TARGET_ARCH"}
+          }
+        ]
+      }
+    }
+  }
+, "compile-deps":
+  { "expression":
+    { "type": "disjoint_map_union"
+    , "$1":
+      { "type": "++"
+      , "$1":
+        [ { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "deps"}
+          , "body":
+            { "type": "DEP_PROVIDES"
+            , "dep": {"type": "var", "name": "dep"}
+            , "provider": "compile-deps"
+            , "default": {"type": "empty_map"}
+            }
+          }
+        , { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "deps"}
+          , "body":
+            {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "dep"}}
+          }
+        , { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "proto-deps"}
+          , "body":
+            { "type": "DEP_PROVIDES"
+            , "dep": {"type": "var", "name": "dep"}
+            , "provider": "compile-deps"
+            , "default": {"type": "empty_map"}
+            }
+          }
+        , { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "proto-deps"}
+          , "body":
+            {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "dep"}}
+          }
+        ]
+      }
+    }
+  }
+, "link-deps":
+  { "expression":
+    { "type": "disjoint_map_union"
+    , "$1":
+      { "type": "++"
+      , "$1":
+        [ { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "deps"}
+          , "body":
+            { "type": "DEP_PROVIDES"
+            , "dep": {"type": "var", "name": "dep"}
+            , "provider": "link-deps"
+            , "default": {"type": "empty_map"}
+            }
+          }
+        , { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "deps"}
+          , "body":
+            {"type": "DEP_ARTIFACTS", "dep": {"type": "var", "name": "dep"}}
+          }
+        , { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "proto-deps"}
+          , "body":
+            { "type": "DEP_PROVIDES"
+            , "dep": {"type": "var", "name": "dep"}
+            , "provider": "link-deps"
+            , "default": {"type": "empty_map"}
+            }
+          }
+        , { "type": "foreach"
+          , "var": "dep"
+          , "range": {"type": "FIELD", "name": "proto-deps"}
+          , "body":
+            {"type": "DEP_ARTIFACTS", "dep": {"type": "var", "name": "dep"}}
+          }
+        ]
+      }
+    }
+  }
+, "objects":
+  { "vars": ["CXX", "CXXFLAGS", "ENV", "srcs", "compile-deps", "local hdrs"]
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "include tree"
+        , { "type": "singleton_map"
+          , "key": "include"
+          , "value":
+            {"type": "TREE", "$1": {"type": "var", "name": "compile-deps"}}
+          }
+        ]
+      , [ "all hdrs"
+        , { "type": "map_union"
+          , "$1":
+            [ {"type": "var", "name": "include tree"}
+            , { "type": "to_subdir"
+              , "subdir": "work"
+              , "$1": {"type": "var", "name": "local hdrs"}
+              }
+            ]
+          }
+        ]
+      ]
+    , "body":
+      { "type": "map_union"
+      , "$1":
+        { "type": "foreach_map"
+        , "var_key": "src_name"
+        , "var_val": "src_val"
+        , "range": {"type": "var", "name": "srcs"}
+        , "body":
+          { "type": "let*"
+          , "bindings":
+            [ [ "work src_name"
+              , { "type": "join"
+                , "separator": "/"
+                , "$1": ["work", {"type": "var", "name": "src_name"}]
+                }
+              ]
+            , [ "inputs"
+              , { "type": "map_union"
+                , "$1":
+                  [ {"type": "var", "name": "all hdrs"}
+                  , { "type": "singleton_map"
+                    , "key": {"type": "var", "name": "work src_name"}
+                    , "value": {"type": "var", "name": "src_val"}
+                    }
+                  ]
+                }
+              ]
+            , [ "out"
+              , { "type": "change_ending"
+                , "$1": {"type": "var", "name": "src_name"}
+                , "ending": ".o"
+                }
+              ]
+            , [ "work out"
+              , { "type": "join"
+                , "separator": "/"
+                , "$1": ["work", {"type": "var", "name": "out"}]
+                }
+              ]
+            , [ "action output"
+              , { "type": "ACTION"
+                , "outs": [{"type": "var", "name": "work out"}]
+                , "inputs": {"type": "var", "name": "inputs"}
+                , "cmd":
+                  { "type": "++"
+                  , "$1":
+                    [ [{"type": "var", "name": "CXX"}]
+                    , {"type": "var", "name": "CXXFLAGS"}
+                    , ["-I", "work", "-isystem", "include"]
+                    , ["-c", {"type": "var", "name": "work src_name"}]
+                    , ["-o", {"type": "var", "name": "work out"}]
+                    ]
+                  }
+                }
+              ]
+            , [ "staged output artifact"
+              , { "type": "map_union"
+                , "$1":
+                  { "type": "foreach_map"
+                  , "range": {"type": "var", "name": "action output"}
+                  , "var_val": "object"
+                  , "body":
+                    { "type": "singleton_map"
+                    , "key": {"type": "var", "name": "out"}
+                    , "value": {"type": "var", "name": "object"}
+                    }
+                  }
+                }
+              ]
+            ]
+          , "body": {"type": "var", "name": "staged output artifact"}
+          }
+        }
+      }
+    }
+  }
+, "lib result":
+  { "vars":
+    [ "CXX"
+    , "CXXFLAGS"
+    , "CC"
+    , "CFLAGS"
+    , "ENV"
+    , "AR"
+    , "srcs"
+    , "hdrs"
+    , "private-hdrs"
+    , "link external"
+    , "extra-provides"
+    ]
+  , "imports":
+    { "artifacts": ["./", "..", "field_artifacts"]
+    , "compile-deps": "compile-deps"
+    , "link-deps": "link-deps"
+    , "objects": "objects"
+    , "default-CC": "default-CC"
+    , "default-CXX": "default-CXX"
+    , "default-CFLAGS": "default-CFLAGS"
+    , "default-CXXFLAGS": "default-CXXFLAGS"
+    , "default-ENV": "default-ENV"
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "CXX"
+        , { "type": "if"
+          , "cond": {"type": "FIELD", "name": "pure C"}
+          , "then":
+            { "type": "var"
+            , "name": "CC"
+            , "default": {"type": "CALL_EXPRESSION", "name": "default-CC"}
+            }
+          , "else":
+            { "type": "var"
+            , "name": "CXX"
+            , "default": {"type": "CALL_EXPRESSION", "name": "default-CXX"}
+            }
+          }
+        ]
+      , [ "CXXFLAGS"
+        , { "type": "if"
+          , "cond": {"type": "FIELD", "name": "pure C"}
+          , "then":
+            { "type": "var"
+            , "name": "CFLAGS"
+            , "default": {"type": "CALL_EXPRESSION", "name": "default-CFLAGS"}
+            }
+          , "else":
+            { "type": "var"
+            , "name": "CXXFLAGS"
+            , "default":
+              {"type": "CALL_EXPRESSION", "name": "default-CXXFLAGS"}
+            }
+          }
+        ]
+      , [ "ENV"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "CALL_EXPRESSION", "name": "default-ENV"}
+              , [ { "type": "var"
+                  , "name": "ENV"
+                  , "default": {"type": "empty_map"}
+                  }
+                ]
+              ]
+            }
+          }
+        ]
+      , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
+      , ["link-deps", {"type": "CALL_EXPRESSION", "name": "link-deps"}]
+      , [ "local hdrs"
+        , { "type": "disjoint_map_union"
+          , "$1":
+            [ {"type": "var", "name": "hdrs"}
+            , {"type": "var", "name": "private-hdrs"}
+            ]
+          }
+        ]
+      , ["objects", {"type": "CALL_EXPRESSION", "name": "objects"}]
+      , [ "base name"
+        , {"type": "join", "$1": {"type": "FIELD", "name": "name"}}
+        ]
+      , [ "libname"
+        , { "type": "join"
+          , "$1": ["lib", {"type": "var", "name": "base name"}, ".a"]
+          }
+        ]
+      , [ "lib"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "objects"}
+          , "else": {"type": "empty_map"}
+          , "then":
+            { "type": "ACTION"
+            , "outs": [{"type": "var", "name": "libname"}]
+            , "inputs": {"type": "var", "name": "objects"}
+            , "cmd":
+              { "type": "++"
+              , "$1":
+                [ [ {"type": "var", "name": "AR", "default": "ar"}
+                  , "cqs"
+                  , {"type": "var", "name": "libname"}
+                  ]
+                , {"type": "keys", "$1": {"type": "var", "name": "objects"}}
+                ]
+              }
+            }
+          }
+        ]
+      , [ "lib"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1": {"type": "var", "name": "lib"}
+          }
+        ]
+      , [ "link-args"
+        , { "type": "nub_right"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "keys", "$1": {"type": "var", "name": "lib"}}
+              , { "type": "++"
+                , "$1":
+                  { "type": "foreach"
+                  , "var": "dep"
+                  , "range": {"type": "FIELD", "name": "deps"}
+                  , "body":
+                    { "type": "DEP_PROVIDES"
+                    , "dep": {"type": "var", "name": "dep"}
+                    , "provider": "link-args"
+                    }
+                  }
+                }
+              , { "type": "++"
+                , "$1":
+                  { "type": "foreach"
+                  , "var": "dep"
+                  , "range": {"type": "FIELD", "name": "proto-deps"}
+                  , "body":
+                    { "type": "DEP_PROVIDES"
+                    , "dep": {"type": "var", "name": "dep"}
+                    , "provider": "link-args"
+                    }
+                  }
+                }
+              , {"type": "var", "name": "link external", "default": []}
+              ]
+            }
+          }
+        ]
+      ]
+    , "body":
+      { "type": "RESULT"
+      , "artifacts": {"type": "var", "name": "lib"}
+      , "runfiles": {"type": "var", "name": "hdrs"}
+      , "provides":
+        { "type": "map_union"
+        , "$1":
+          [ { "type": "singleton_map"
+            , "key": "compile-deps"
+            , "value": {"type": "var", "name": "compile-deps"}
+            }
+          , { "type": "singleton_map"
+            , "key": "link-deps"
+            , "value": {"type": "var", "name": "link-deps"}
+            }
+          , { "type": "singleton_map"
+            , "key": "link-args"
+            , "value": {"type": "var", "name": "link-args"}
+            }
+          , { "type": "var"
+            , "name": "extra-provides"
+            , "default": {"type": "empty_map"}
+            }
+          ]
+        }
+      }
+    }
+  }
+}
diff --git a/CC/RULES b/CC/RULES
new file mode 100644
index 0000000..93d5afc
--- /dev/null
+++ b/CC/RULES
@@ -0,0 +1,538 @@
+{ "defaults":
+  { "doc":
+    [ "A rule to provide defaults."
+    , "All CC targets take their defaults for CXX, CC, flags, etc from"
+    , "the target [\"CC\", \"defaults\"]. This is probably the only sensibe"
+    , "use of this rule. As targets form a different root, the defaults"
+    , "can be provided without changing this directory."
+    ]
+  , "string_fields": ["CC", "CXX", "CFLAGS", "CXXFLAGS", "PATH", "AR"]
+  , "expression":
+    { "type": "RESULT"
+    , "provides":
+      { "type": "map_union"
+      , "$1":
+        [ { "type": "singleton_map"
+          , "key": "CC"
+          , "value": {"type": "FIELD", "name": "CC"}
+          }
+        , { "type": "singleton_map"
+          , "key": "CXX"
+          , "value": {"type": "FIELD", "name": "CXX"}
+          }
+        , { "type": "singleton_map"
+          , "key": "CFLAGS"
+          , "value": {"type": "FIELD", "name": "CFLAGS"}
+          }
+        , { "type": "singleton_map"
+          , "key": "CXXFLAGS"
+          , "value": {"type": "FIELD", "name": "CXXFLAGS"}
+          }
+        , { "type": "singleton_map"
+          , "key": "AR"
+          , "value": {"type": "FIELD", "name": "AR"}
+          }
+        , { "type": "singleton_map"
+          , "key": "ENV"
+          , "value":
+            { "type": "singleton_map"
+            , "key": "PATH"
+            , "value":
+              { "type": "join"
+              , "separator": ":"
+              , "$1": {"type": "FIELD", "name": "PATH"}
+              }
+            }
+          }
+        ]
+      }
+    }
+  }
+, "configure":
+  { "doc":
+    [ "A rule to provide a static platform configuration for a target."
+    , "The artifacts and runfiles of the specified target will be propagated."
+    , "The target defined by this rule does not propagate any provides data."
+    ]
+  , "config_fields": ["os", "arch", "target_arch"]
+  , "target_fields": ["target"]
+  , "field_doc":
+    { "os": ["The operation system used for building."]
+    , "arch": ["The architecture used for building."]
+    , "target_arch":
+      [ "Non-mandatory target architecture to build for. If omitted, target"
+      , "architecture is derived from \"arch\"."
+      ]
+    , "target":
+      [ "The target to configure. Multiple targets are supported, but their"
+      , "artifacts and runfiles should not conflict."
+      ]
+    }
+  , "imports":
+    { "transition": "configure transition"
+    , "artifacts": ["./", "..", "field_artifacts"]
+    , "runfiles": ["./", "..", "field_runfiles"]
+    }
+  , "config_transitions":
+    {"target": [{"type": "CALL_EXPRESSION", "name": "transition"}]}
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ ["fieldname", "target"]
+      , ["transition", {"type": "CALL_EXPRESSION", "name": "transition"}]
+      ]
+    , "body":
+      { "type": "RESULT"
+      , "artifacts": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+      , "runfiles": {"type": "CALL_EXPRESSION", "name": "runfiles"}
+      }
+    }
+  }
+, "header directory":
+  { "doc":
+    [ "A directory of header files."
+    , ""
+    , "Define a directory of  header files that belong together and are staged"
+    , "in such a way that no other target (used together with this target) will"
+    , "have to put files in this directory. The typical use case is a library"
+    , "libfoo that expects all headers to be included as #include \"foo/bar.h\"."
+    , "In this case, one would define a header direcotry for \"foo\"."
+    , ""
+    , "Technically, a tree is created from the given files and staged to the"
+    , "specified location. Since trees are opaque, the directory name becomes"
+    , "essentially owned by target. In this way, staging conflicts can be"
+    , "avoided by detecting them early and not only once a file with the same"
+    , "name is  added to the staging location. Also, as only a tree identifier"
+    , "has to be passed around, such a directory can be handled more"
+    , "efficiently by the tool."
+    ]
+  , "target_fields": ["hdrs"]
+  , "string_fields": ["stage", "public stage"]
+  , "field_doc":
+    { "hdrs": ["The header files to be put into the header directory."]
+    , "stage":
+      [ "The location of the header directory."
+      , "Path segments are joined with \"/\"."
+      ]
+    , "public stage":
+      [ "If non-empty, no closure for the header directory's stage is created, "
+      , "so can be combined with other header directories having the same "
+      , "public staging directory."
+      ]
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "hdrs"
+        , { "type": "disjoint_map_union"
+          , "$1":
+            { "type": "foreach"
+            , "var": "x"
+            , "range": {"type": "FIELD", "name": "hdrs"}
+            , "body":
+              {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
+            }
+          }
+        ]
+      , [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "dir"
+        , { "type": "if"
+          , "cond": {"type": "FIELD", "name": "public stage"}
+          , "then":
+            { "type": "to_subdir"
+            , "subdir": {"type": "var", "name": "stage"}
+            , "$1": {"type": "var", "name": "hdrs"}
+            }
+          , "else":
+            { "type": "singleton_map"
+            , "key": {"type": "var", "name": "stage"}
+            , "value": {"type": "TREE", "$1": {"type": "var", "name": "hdrs"}}
+            }
+          }
+        ]
+      ]
+    , "body":
+      { "type": "RESULT"
+      , "artifacts": {"type": "var", "name": "dir"}
+      , "runfiles": {"type": "var", "name": "dir"}
+      }
+    }
+  }
+, "library":
+  { "doc": ["A C++ libaray"]
+  , "target_fields": ["srcs", "hdrs", "private-hdrs", "deps", "proto"]
+  , "string_fields":
+    ["name", "stage", "pure C", "local defines", "link external"]
+  , "config_vars": ["CXX", "CC", "CXXFLAGS", "CFLAGS", "ENV", "AR"]
+  , "implicit": {"defaults": ["defaults"]}
+  , "field_doc":
+    { "name":
+      ["The name of the library (without leading \"lib\" or trailing \".a\""]
+    , "srcs": ["The source files of the library."]
+    , "hdrs": ["Any public header files of the library."]
+    , "private-hdrs":
+      [ "Any header files that only need to be present when compiling the"
+      , "source files, but are not needed for any consumer of the library"
+      ]
+    , "stage":
+      [ "The logical location of all header and source files, as well as the"
+      , "resulting library file. Individual directory components are joined"
+      , "with \"/\"."
+      ]
+    , "pure C":
+      [ "If non-empty, compile as C sources rathter than C++ sources."
+      , "In particular, CC is used to compile rather than CXX"
+      ]
+    , "local defines":
+      [ "List of defines set for source files local to this target."
+      , "Each list entry will be prepended by \"-D\"."
+      ]
+    , "link external":
+      ["Additional linker flags for linking external libraries."]
+    , "deps": ["Any other libraries this library depends upon."]
+    }
+  , "config_doc":
+    { "CXX": ["The name of the C++ compiler to be used."]
+    , "CC":
+      ["The name of the C compiler to be used (when compiling pure C code)"]
+    , "AR": ["The archive tool to used for creating the library"]
+    , "ENV": ["The environment for any action generated."]
+    , "CXXFLAGS":
+      [ "The flags for CXX to be used instead of the default ones."
+      , "For libraries that should be built in a non-standard way; usually"
+      , "adapting the default target [\"CC\", \"defaults\"] is the better"
+      , "choice"
+      ]
+    , "CFLAGS":
+      [ "The flags for CC to be used instead of the default ones."
+      , "For libraries that should be built in a non-standard way; usually"
+      , "adapting the default target [\"CC\", \"defaults\"] is the better"
+      , "choice"
+      ]
+    }
+  , "anonymous":
+    { "proto-deps":
+      { "target": "proto"
+      , "provider": "proto"
+      , "rule_map":
+        { "library": ["./", "proto", "library"]
+        , "service library": ["./", "proto", "service library"]
+        }
+      }
+    }
+  , "imports":
+    { "artifacts": ["./", "..", "field_artifacts"]
+    , "default-CXXFLAGS": "default-CXXFLAGS"
+    , "default-CFLAGS": "default-CFLAGS"
+    , "result": "lib result"
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "local defines"
+        , { "type": "foreach"
+          , "var": "def"
+          , "range": {"type": "FIELD", "name": "local defines"}
+          , "body":
+            {"type": "join", "$1": ["-D", {"type": "var", "name": "def"}]}
+          }
+        ]
+      , [ "CFLAGS"
+        , { "type": "++"
+          , "$1":
+            [ { "type": "var"
+              , "name": "CFLAGS"
+              , "default":
+                {"type": "CALL_EXPRESSION", "name": "default-CFLAGS"}
+              }
+            , {"type": "var", "name": "local defines"}
+            ]
+          }
+        ]
+      , [ "CXXFLAGS"
+        , { "type": "++"
+          , "$1":
+            [ { "type": "var"
+              , "name": "CXXFLAGS"
+              , "default":
+                {"type": "CALL_EXPRESSION", "name": "default-CXXFLAGS"}
+              }
+            , {"type": "var", "name": "local defines"}
+            ]
+          }
+        ]
+      , [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "srcs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "srcs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , [ "hdrs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "hdrs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , [ "private-hdrs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "private-hdrs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , ["link external", {"type": "FIELD", "name": "link external"}]
+      ]
+    , "body": {"type": "CALL_EXPRESSION", "name": "result"}
+    }
+  }
+, "binary":
+  { "doc": ["A binary written in C++"]
+  , "target_fields": ["srcs", "private-hdrs", "deps", "proto"]
+  , "string_fields":
+    ["name", "stage", "pure C", "local defines", "link external"]
+  , "config_vars": ["CXX", "CC", "CXXFLAGS", "CFLAGS", "ENV"]
+  , "implicit": {"defaults": ["defaults"]}
+  , "field_doc":
+    { "name": ["The name of the binary"]
+    , "srcs": ["The source files of the library."]
+    , "private-hdrs":
+      [ "Any header files that need to be present when compiling the"
+      , "source files."
+      ]
+    , "stage":
+      [ "The logical location of all header and source files, as well as the"
+      , "resulting binary file. Individual directory components are joined"
+      , "with \"/\"."
+      ]
+    , "pure C":
+      [ "If non-empty, compile as C sources rathter than C++ sources."
+      , "In particular, CC is used to compile rather than CXX"
+      ]
+    , "local defines":
+      [ "List of defines set for source files local to this target."
+      , "Each list entry will be prepended by \"-D\"."
+      ]
+    , "link external":
+      ["Additional linker flags for linking external libraries."]
+    , "deps": ["Any other libraries this binary depends upon."]
+    }
+  , "config_doc":
+    { "CXX": ["The name of the C++ compiler to be used."]
+    , "CC":
+      ["The name of the C compiler to be used (when compiling pure C code)"]
+    , "ENV": ["The environment for any action generated."]
+    , "CXXFLAGS":
+      [ "The flags for CXX to be used instead of the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
+    , "CFLAGS":
+      [ "The flags for CXX to be used instead of the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
+    }
+  , "anonymous":
+    { "proto-deps":
+      { "target": "proto"
+      , "provider": "proto"
+      , "rule_map":
+        { "library": ["./", "proto", "library"]
+        , "service library": ["./", "proto", "service library"]
+        }
+      }
+    }
+  , "imports":
+    { "artifacts": ["./", "..", "field_artifacts"]
+    , "compile-deps": "compile-deps"
+    , "link-deps": "link-deps"
+    , "objects": "objects"
+    , "default-CC": "default-CC"
+    , "default-CXX": "default-CXX"
+    , "default-CFLAGS": "default-CFLAGS"
+    , "default-CXXFLAGS": "default-CXXFLAGS"
+    , "default-ENV": "default-ENV"
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "local defines"
+        , { "type": "foreach"
+          , "var": "def"
+          , "range": {"type": "FIELD", "name": "local defines"}
+          , "body":
+            {"type": "join", "$1": ["-D", {"type": "var", "name": "def"}]}
+          }
+        ]
+      , [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "srcs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "srcs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , [ "local hdrs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "private-hdrs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , [ "CXX"
+        , { "type": "if"
+          , "cond": {"type": "FIELD", "name": "pure C"}
+          , "then":
+            { "type": "var"
+            , "name": "CC"
+            , "default": {"type": "CALL_EXPRESSION", "name": "default-CC"}
+            }
+          , "else":
+            { "type": "var"
+            , "name": "CXX"
+            , "default": {"type": "CALL_EXPRESSION", "name": "default-CXX"}
+            }
+          }
+        ]
+      , [ "CXXFLAGS"
+        , { "type": "if"
+          , "cond": {"type": "FIELD", "name": "pure C"}
+          , "then":
+            { "type": "var"
+            , "name": "CFLAGS"
+            , "default": {"type": "CALL_EXPRESSION", "name": "default-CFLAGS"}
+            }
+          , "else":
+            { "type": "var"
+            , "name": "CXXFLAGS"
+            , "default":
+              {"type": "CALL_EXPRESSION", "name": "default-CXXFLAGS"}
+            }
+          }
+        ]
+      , [ "CXXFLAGS"
+        , { "type": "++"
+          , "$1":
+            [ {"type": "var", "name": "CXXFLAGS"}
+            , {"type": "var", "name": "local defines"}
+            ]
+          }
+        ]
+      , [ "ENV"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "CALL_EXPRESSION", "name": "default-ENV"}
+              , [ { "type": "var"
+                  , "name": "ENV"
+                  , "default": {"type": "empty_map"}
+                  }
+                ]
+              ]
+            }
+          }
+        ]
+      , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
+      , ["link-deps", {"type": "CALL_EXPRESSION", "name": "link-deps"}]
+      , ["objects", {"type": "CALL_EXPRESSION", "name": "objects"}]
+      , [ "base name"
+        , {"type": "join", "$1": {"type": "FIELD", "name": "name"}}
+        ]
+      , [ "binary name"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "stage"}
+          , "else": {"type": "var", "name": "base name"}
+          , "then":
+            { "type": "join"
+            , "separator": "/"
+            , "$1":
+              [ {"type": "var", "name": "stage"}
+              , {"type": "var", "name": "base name"}
+              ]
+            }
+          }
+        ]
+      , [ "link-args"
+        , { "type": "nub_right"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "keys", "$1": {"type": "var", "name": "objects"}}
+              , { "type": "++"
+                , "$1":
+                  { "type": "foreach"
+                  , "var": "dep"
+                  , "range": {"type": "FIELD", "name": "deps"}
+                  , "body":
+                    { "type": "DEP_PROVIDES"
+                    , "dep": {"type": "var", "name": "dep"}
+                    , "provider": "link-args"
+                    }
+                  }
+                }
+              , {"type": "FIELD", "name": "link external"}
+              ]
+            }
+          }
+        ]
+      , [ "binary"
+        , { "type": "ACTION"
+          , "outs": [{"type": "var", "name": "binary name"}]
+          , "inputs":
+            { "type": "disjoint_map_union"
+            , "$1":
+              [ {"type": "var", "name": "objects"}
+              , {"type": "var", "name": "link-deps"}
+              ]
+            }
+          , "cmd":
+            { "type": "++"
+            , "$1":
+              [ [ {"type": "var", "name": "CXX"}
+                , "-o"
+                , {"type": "var", "name": "binary name"}
+                ]
+              , {"type": "var", "name": "link-args"}
+              ]
+            }
+          , "env": {"type": "var", "name": "ENV"}
+          }
+        ]
+      ]
+    , "body":
+      {"type": "RESULT", "artifacts": {"type": "var", "name": "binary"}}
+    }
+  }
+}
diff --git a/CC/proto/EXPRESSIONS b/CC/proto/EXPRESSIONS
new file mode 100644
index 0000000..a98c51c
--- /dev/null
+++ b/CC/proto/EXPRESSIONS
@@ -0,0 +1,301 @@
+{ "protoc-deps":
+  { "expression":
+    { "type": "disjoint_map_union"
+    , "$1":
+      { "type": "foreach"
+      , "var": "dep"
+      , "range": {"type": "FIELD", "name": "deps"}
+      , "body":
+        { "type": "DEP_PROVIDES"
+        , "dep": {"type": "var", "name": "dep"}
+        , "provider": "protoc-deps"
+        , "default": {"type": "empty_map"}
+        }
+      }
+    }
+  }
+, "protoc-compile":
+  { "vars": ["transition", "service support"]
+  , "imports":
+    { "stage": ["", "stage_singleton_field"]
+    , "result": ["./", "..", "lib result"]
+    , "field_runfiles": ["", "field_runfiles"]
+    , "protoc-deps": "protoc-deps"
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "protoc"
+        , { "type": "let*"
+          , "bindings": [["fieldname", "protoc"], ["location", "protoc"]]
+          , "body": {"type": "CALL_EXPRESSION", "name": "stage"}
+          }
+        ]
+      , [ "grpc_cpp_plugin"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "service support"}
+          , "then":
+            { "type": "let*"
+            , "bindings":
+              [ ["fieldname", "grpc_cpp_plugin"]
+              , ["location", "grpc_cpp_plugin"]
+              ]
+            , "body": {"type": "CALL_EXPRESSION", "name": "stage"}
+            }
+          , "else": {"type": "empty_map"}
+          }
+        ]
+      , ["protoc-deps", {"type": "CALL_EXPRESSION", "name": "protoc-deps"}]
+      , [ "proto deps"
+        , { "type": "to_subdir"
+          , "subdir": "work"
+          , "$1":
+            { "type": "disjoint_map_union"
+            , "$1":
+              { "type": "foreach"
+              , "var": "x"
+              , "range": {"type": "FIELD", "name": "well_known_protos"}
+              , "body":
+                {"type": "DEP_ARTIFACTS", "dep": {"type": "var", "name": "x"}}
+              }
+            }
+          }
+        ]
+      , [ "proto srcs"
+        , { "type": "disjoint_map_union"
+          , "msg": "Sources may not conflict"
+          , "$1":
+            { "type": "foreach"
+            , "var": "x"
+            , "range": {"type": "FIELD", "name": "srcs"}
+            , "body":
+              {"type": "DEP_ARTIFACTS", "dep": {"type": "var", "name": "x"}}
+            }
+          }
+        ]
+      , [ "all proto srcs"
+        , { "type": "disjoint_map_union"
+          , "msg": "Conflict with proto files of dependencies"
+          , "$1":
+            [ {"type": "var", "name": "protoc-deps"}
+            , {"type": "var", "name": "proto srcs"}
+            ]
+          }
+        ]
+      , [ "staged srcs"
+        , { "type": "to_subdir"
+          , "subdir": "work"
+          , "$1": {"type": "var", "name": "proto srcs"}
+          }
+        ]
+      , [ "staged all proto srcs"
+        , { "type": "to_subdir"
+          , "subdir": "work"
+          , "$1": {"type": "var", "name": "all proto srcs"}
+          }
+        ]
+      , [ "outs"
+        , { "type": "++"
+          , "$1":
+            { "type": "foreach"
+            , "var": "f"
+            , "range":
+              {"type": "keys", "$1": {"type": "var", "name": "staged srcs"}}
+            , "body":
+              { "type": "++"
+              , "$1":
+                [ [ { "type": "change_ending"
+                    , "$1": {"type": "var", "name": "f"}
+                    , "ending": ".pb.h"
+                    }
+                  , { "type": "change_ending"
+                    , "$1": {"type": "var", "name": "f"}
+                    , "ending": ".pb.cc"
+                    }
+                  ]
+                , { "type": "if"
+                  , "cond": {"type": "var", "name": "service support"}
+                  , "then":
+                    [ { "type": "change_ending"
+                      , "$1": {"type": "var", "name": "f"}
+                      , "ending": ".grpc.pb.h"
+                      }
+                    , { "type": "change_ending"
+                      , "$1": {"type": "var", "name": "f"}
+                      , "ending": ".grpc.pb.cc"
+                      }
+                    ]
+                  , "else": []
+                  }
+                ]
+              }
+            }
+          }
+        ]
+      , [ "cmd"
+        , { "type": "++"
+          , "$1":
+            [ ["./protoc", "--proto_path=work", "--cpp_out=work"]
+            , { "type": "if"
+              , "cond": {"type": "var", "name": "service support"}
+              , "then":
+                [ "--grpc_out=work"
+                , "--plugin=protoc-gen-grpc=./grpc_cpp_plugin"
+                ]
+              , "else": []
+              }
+            , {"type": "keys", "$1": {"type": "var", "name": "staged srcs"}}
+            ]
+          }
+        ]
+      , [ "generated"
+        , { "type": "ACTION"
+          , "inputs":
+            { "type": "map_union"
+            , "$1":
+              [ {"type": "var", "name": "staged all proto srcs"}
+              , {"type": "var", "name": "protoc"}
+              , {"type": "var", "name": "grpc_cpp_plugin"}
+              , {"type": "var", "name": "proto deps"}
+              ]
+            }
+          , "outs": {"type": "var", "name": "outs"}
+          , "cmd": {"type": "var", "name": "cmd"}
+          }
+        ]
+      , [ "srcs"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "foreach"
+            , "var": "name"
+            , "range":
+              {"type": "keys", "$1": {"type": "var", "name": "proto srcs"}}
+            , "body":
+              { "type": "map_union"
+              , "$1":
+                [ { "type": "singleton_map"
+                  , "key":
+                    { "type": "change_ending"
+                    , "$1": {"type": "var", "name": "name"}
+                    , "ending": ".pb.cc"
+                    }
+                  , "value":
+                    { "type": "lookup"
+                    , "map": {"type": "var", "name": "generated"}
+                    , "key":
+                      { "type": "join"
+                      , "$1":
+                        [ "work/"
+                        , { "type": "change_ending"
+                          , "$1": {"type": "var", "name": "name"}
+                          , "ending": ".pb.cc"
+                          }
+                        ]
+                      }
+                    }
+                  }
+                , { "type": "if"
+                  , "cond": {"type": "var", "name": "service support"}
+                  , "then":
+                    { "type": "singleton_map"
+                    , "key":
+                      { "type": "change_ending"
+                      , "$1": {"type": "var", "name": "name"}
+                      , "ending": ".grpc.pb.cc"
+                      }
+                    , "value":
+                      { "type": "lookup"
+                      , "map": {"type": "var", "name": "generated"}
+                      , "key":
+                        { "type": "join"
+                        , "$1":
+                          [ "work/"
+                          , { "type": "change_ending"
+                            , "$1": {"type": "var", "name": "name"}
+                            , "ending": ".grpc.pb.cc"
+                            }
+                          ]
+                        }
+                      }
+                    }
+                  , "else": {"type": "empty_map"}
+                  }
+                ]
+              }
+            }
+          }
+        ]
+      , [ "hdrs"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "foreach"
+            , "var": "name"
+            , "range":
+              {"type": "keys", "$1": {"type": "var", "name": "proto srcs"}}
+            , "body":
+              { "type": "map_union"
+              , "$1":
+                [ { "type": "singleton_map"
+                  , "key":
+                    { "type": "change_ending"
+                    , "$1": {"type": "var", "name": "name"}
+                    , "ending": ".pb.h"
+                    }
+                  , "value":
+                    { "type": "lookup"
+                    , "map": {"type": "var", "name": "generated"}
+                    , "key":
+                      { "type": "join"
+                      , "$1":
+                        [ "work/"
+                        , { "type": "change_ending"
+                          , "$1": {"type": "var", "name": "name"}
+                          , "ending": ".pb.h"
+                          }
+                        ]
+                      }
+                    }
+                  }
+                , { "type": "if"
+                  , "cond": {"type": "var", "name": "service support"}
+                  , "then":
+                    { "type": "singleton_map"
+                    , "key":
+                      { "type": "change_ending"
+                      , "$1": {"type": "var", "name": "name"}
+                      , "ending": ".grpc.pb.h"
+                      }
+                    , "value":
+                      { "type": "lookup"
+                      , "map": {"type": "var", "name": "generated"}
+                      , "key":
+                        { "type": "join"
+                        , "$1":
+                          [ "work/"
+                          , { "type": "change_ending"
+                            , "$1": {"type": "var", "name": "name"}
+                            , "ending": ".grpc.pb.h"
+                            }
+                          ]
+                        }
+                      }
+                    }
+                  , "else": {"type": "empty_map"}
+                  }
+                ]
+              }
+            }
+          }
+        ]
+      , ["private-hdrs", {"type": "empty_map"}]
+      , [ "extra-provides"
+        , { "type": "singleton_map"
+          , "key": "protoc-deps"
+          , "value": {"type": "var", "name": "all proto srcs"}
+          }
+        ]
+      ]
+    , "body": {"type": "CALL_EXPRESSION", "name": "result"}
+    }
+  }
+}
diff --git a/CC/proto/RULES b/CC/proto/RULES
new file mode 100644
index 0000000..04082c1
--- /dev/null
+++ b/CC/proto/RULES
@@ -0,0 +1,72 @@
+{ "library":
+  { "doc":
+    [ "A library C++ library, generated from proto files."
+    , ""
+    , "This rule usually is used to bind anonymous targets generated from"
+    , "proto libraries."
+    ]
+  , "string_fields": ["name", "stage"]
+  , "target_fields": ["srcs", "deps"]
+  , "config_vars":
+    ["OS", "ARCH", "HOST_ARCH", "CXX", "CC", "CXXFLAGS", "CFLAGS", "ENV", "AR"]
+  , "implicit":
+    { "protoc": [["@", "protoc", "", "protoc"]]
+    , "defaults": [["./", "..", "defaults"]]
+    , "proto-deps": [["@", "protoc", "", "C++ runtime"]]
+    , "well_known_protos": [["@", "protoc", "", "well_known_protos"]]
+    , "pure C": []
+    }
+  , "imports":
+    { "protoc-compile": "protoc-compile"
+    , "host transition": ["transitions", "for host"]
+    }
+  , "config_transitions":
+    {"protoc": [{"type": "CALL_EXPRESSION", "name": "host transition"}]}
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [["transition", {"type": "CALL_EXPRESSION", "name": "host transition"}]]
+    , "body": {"type": "CALL_EXPRESSION", "name": "protoc-compile"}
+    }
+  }
+, "service library":
+  { "doc":
+    [ "A service library C++ library, generated from proto files."
+    , ""
+    , "Calls protoc with gRPC plugin to additionally generate gRPC services"
+    , "from proto libraries."
+    ]
+  , "string_fields": ["name", "stage"]
+  , "target_fields": ["srcs", "deps"]
+  , "config_vars":
+    ["OS", "ARCH", "HOST_ARCH", "CXX", "CC", "CXXFLAGS", "CFLAGS", "ENV", "AR"]
+  , "implicit":
+    { "protoc": [["@", "protoc", "", "protoc"]]
+    , "grpc_cpp_plugin": [["@", "grpc", "src/compiler", "grpc_cpp_plugin"]]
+    , "defaults": [["./", "..", "defaults"]]
+    , "proto-deps":
+      [ ["@", "grpc", "", "grpc++_codegen_proto"]
+      , ["@", "protoc", "", "C++ runtime"]
+      ]
+    , "well_known_protos": [["@", "protoc", "", "well_known_protos"]]
+    , "pure C": []
+    }
+  , "imports":
+    { "protoc-compile": "protoc-compile"
+    , "host transition": ["transitions", "for host"]
+    }
+  , "config_transitions":
+    { "protoc": [{"type": "CALL_EXPRESSION", "name": "host transition"}]
+    , "grpc_cpp_plugin":
+      [{"type": "CALL_EXPRESSION", "name": "host transition"}]
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ ["service support", true]
+      , ["transition", {"type": "CALL_EXPRESSION", "name": "host transition"}]
+      ]
+    , "body": {"type": "CALL_EXPRESSION", "name": "protoc-compile"}
+    }
+  }
+}
diff --git a/CC/test/RULES b/CC/test/RULES
new file mode 100644
index 0000000..de5a485
--- /dev/null
+++ b/CC/test/RULES
@@ -0,0 +1,265 @@
+{ "test":
+  { "doc":
+    [ "A test written in C++"
+    , "FIXME: the test binary and data must be built for host"
+    ]
+  , "tainted": ["test"]
+  , "target_fields": ["srcs", "private-hdrs", "deps", "data"]
+  , "string_fields": ["name", "stage"]
+  , "config_vars": ["CXX", "CC", "CXXFLAGS", "CFLAGS", "ENV"]
+  , "implicit":
+    { "defaults": [["./", "..", "defaults"]]
+    , "proto-deps": []
+    , "runner": ["test_runner.sh"]
+    }
+  , "field_doc":
+    { "name":
+      [ "The name of the test"
+      , ""
+      , "Used to name the test binary as well as for staging the test result"
+      ]
+    , "srcs": ["The sources of the test binary"]
+    , "private-hdrs":
+      [ "Any additional header files that need to be present when compiling"
+      , "the test binary."
+      ]
+    , "stage":
+      [ "The logical location of all header and source files."
+      , "Individual directory components are joined with \"/\"."
+      ]
+    , "data": ["Any files the test binary needs access to when running"]
+    }
+  , "config_doc":
+    { "CXX": ["The name of the C++ compiler to be used."]
+    , "ENV": ["The environment for any action generated."]
+    , "CXXFLAGS":
+      [ "The flags for CXX to be used instead of the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
+    }
+  , "imports":
+    { "artifacts": ["./", "../..", "field_artifacts"]
+    , "compile-deps": ["./", "..", "compile-deps"]
+    , "link-deps": ["./", "..", "link-deps"]
+    , "objects": ["./", "..", "objects"]
+    , "default-CXX": ["./", "..", "default-CXX"]
+    , "default-CXXFLAGS": ["./", "..", "default-CXXFLAGS"]
+    , "default-ENV": ["./", "..", "default-ENV"]
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "srcs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "srcs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , [ "local hdrs"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1":
+            { "type": "let*"
+            , "bindings": [["fieldname", "private-hdrs"]]
+            , "body": {"type": "CALL_EXPRESSION", "name": "artifacts"}
+            }
+          }
+        ]
+      , [ "CXX"
+        , { "type": "var"
+          , "name": "CXX"
+          , "default": {"type": "CALL_EXPRESSION", "name": "default-CXX"}
+          }
+        ]
+      , [ "CXXFLAGS"
+        , { "type": "var"
+          , "name": "CXXFLAGS"
+          , "default": {"type": "CALL_EXPRESSION", "name": "default-CXXFLAGS"}
+          }
+        ]
+      , [ "ENV"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "CALL_EXPRESSION", "name": "default-ENV"}
+              , [ { "type": "var"
+                  , "name": "ENV"
+                  , "default": {"type": "empty_map"}
+                  }
+                ]
+              ]
+            }
+          }
+        ]
+      , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
+      , ["link-deps", {"type": "CALL_EXPRESSION", "name": "link-deps"}]
+      , ["objects", {"type": "CALL_EXPRESSION", "name": "objects"}]
+      , [ "base name"
+        , { "type": "assert_non_empty"
+          , "msg": "A non-empy name has to be provided"
+          , "$1": {"type": "join", "$1": {"type": "FIELD", "name": "name"}}
+          }
+        ]
+      , [ "binary name"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "stage"}
+          , "else": {"type": "var", "name": "base name"}
+          , "then":
+            { "type": "join"
+            , "separator": "/"
+            , "$1":
+              [ {"type": "var", "name": "stage"}
+              , {"type": "var", "name": "base name"}
+              ]
+            }
+          }
+        ]
+      , [ "link-args"
+        , { "type": "nub_right"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "keys", "$1": {"type": "var", "name": "objects"}}
+              , { "type": "++"
+                , "$1":
+                  { "type": "foreach"
+                  , "var": "dep"
+                  , "range": {"type": "FIELD", "name": "deps"}
+                  , "body":
+                    { "type": "DEP_PROVIDES"
+                    , "dep": {"type": "var", "name": "dep"}
+                    , "provider": "link-args"
+                    }
+                  }
+                }
+              ]
+            }
+          }
+        ]
+      , [ "binary"
+        , { "type": "ACTION"
+          , "outs": [{"type": "var", "name": "binary name"}]
+          , "inputs":
+            { "type": "disjoint_map_union"
+            , "$1":
+              [ {"type": "var", "name": "objects"}
+              , {"type": "var", "name": "link-deps"}
+              ]
+            }
+          , "cmd":
+            { "type": "++"
+            , "$1":
+              [ [ {"type": "var", "name": "CXX"}
+                , "-o"
+                , {"type": "var", "name": "binary name"}
+                ]
+              , {"type": "var", "name": "link-args"}
+              ]
+            }
+          , "env": {"type": "var", "name": "ENV"}
+          }
+        ]
+      , [ "staged test binary"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "foreach_map"
+            , "range": {"type": "var", "name": "binary"}
+            , "var_val": "binary"
+            , "body":
+              { "type": "singleton_map"
+              , "key": "test"
+              , "value": {"type": "var", "name": "binary"}
+              }
+            }
+          }
+        ]
+      , [ "runner"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "foreach"
+            , "var": "runner"
+            , "range": {"type": "FIELD", "name": "runner"}
+            , "body":
+              { "type": "map_union"
+              , "$1":
+                { "type": "foreach"
+                , "var": "runner"
+                , "range":
+                  { "type": "values"
+                  , "$1":
+                    { "type": "DEP_ARTIFACTS"
+                    , "dep": {"type": "var", "name": "runner"}
+                    }
+                  }
+                , "body":
+                  { "type": "singleton_map"
+                  , "key": "runner.sh"
+                  , "value": {"type": "var", "name": "runner"}
+                  }
+                }
+              }
+            }
+          }
+        ]
+      , [ "data"
+        , { "type": "disjoint_map_union"
+          , "msg": "Data runfiles may not conflict"
+          , "$1":
+            { "type": "foreach"
+            , "var": "dep"
+            , "range": {"type": "FIELD", "name": "data"}
+            , "body":
+              {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "dep"}}
+            }
+          }
+        ]
+      , [ "test-results"
+        , { "type": "ACTION"
+          , "outs": ["result", "stdout", "stderr", "time-start", "time-stop"]
+          , "inputs":
+            { "type": "map_union"
+            , "$1":
+              [ { "type": "to_subdir"
+                , "subdir": "work"
+                , "$1": {"type": "var", "name": "data"}
+                }
+              , {"type": "var", "name": "runner"}
+              , {"type": "var", "name": "staged test binary"}
+              ]
+            }
+          , "cmd": ["sh", "./runner.sh"]
+          , "may_fail": ["test"]
+          , "fail_message":
+            { "type": "join"
+            , "$1":
+              ["CC test ", {"type": "var", "name": "binary name"}, " failed"]
+            }
+          }
+        ]
+      , [ "runfiles"
+        , { "type": "singleton_map"
+          , "key": {"type": "var", "name": "base name"}
+          , "value":
+            {"type": "TREE", "$1": {"type": "var", "name": "test-results"}}
+          }
+        ]
+      ]
+    , "body":
+      { "type": "RESULT"
+      , "artifacts": {"type": "var", "name": "test-results"}
+      , "runfiles": {"type": "var", "name": "runfiles"}
+      }
+    }
+  }
+}
diff --git a/CC/test/test_runner.sh b/CC/test/test_runner.sh
new file mode 100644
index 0000000..ed9f48a
--- /dev/null
+++ b/CC/test/test_runner.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+# ensure all required outputs are present
+touch stdout
+touch stderr
+RESULT=UNKNOWN
+echo "${RESULT}" > result
+echo UNKNOWN > time-start
+echo UNKNOWN > time-stop
+
+mkdir scratch
+export TEST_TMPDIR=$(realpath scratch)
+# Change to the working directory; note: the test might not
+# have test data, so we have to ensure the presence of the work
+# directory.
+
+mkdir -p work
+cd work
+
+date +%s > ../time-start
+# TODO:
+# - proper wrapping with timeout
+# - test arguments to select specific test cases
+if ../test > ../stdout 2> ../stderr
+then
+    RESULT=PASS
+else
+    RESULT=FAIL
+fi
+date +%s > ../time-stop
+echo "${RESULT}" > result
+
+if [ "${RESULT}" '!=' PASS ]
+then
+   exit 1;
+fi
diff --git a/EXPRESSIONS b/EXPRESSIONS
new file mode 100644
index 0000000..9b35b0a
--- /dev/null
+++ b/EXPRESSIONS
@@ -0,0 +1,89 @@
+{ "field_artifacts":
+  { "vars": ["fieldname", "transition"]
+  , "expression":
+    { "type": "map_union"
+    , "$1":
+      { "type": "foreach"
+      , "var": "x"
+      , "range":
+        {"type": "FIELD", "name": {"type": "var", "name": "fieldname"}}
+      , "body":
+        { "type": "DEP_ARTIFACTS"
+        , "dep": {"type": "var", "name": "x"}
+        , "transition":
+          { "type": "var"
+          , "name": "transition"
+          , "default": {"type": "empty_map"}
+          }
+        }
+      }
+    }
+  }
+, "field_runfiles":
+  { "vars": ["fieldname", "transition"]
+  , "expression":
+    { "type": "map_union"
+    , "$1":
+      { "type": "foreach"
+      , "var": "x"
+      , "range":
+        {"type": "FIELD", "name": {"type": "var", "name": "fieldname"}}
+      , "body":
+        { "type": "DEP_RUNFILES"
+        , "dep": {"type": "var", "name": "x"}
+        , "transition":
+          { "type": "var"
+          , "name": "transition"
+          , "default": {"type": "empty_map"}
+          }
+        }
+      }
+    }
+  }
+, "action_env":
+  { "vars": ["ENV"]
+  , "expression":
+    { "type": "map_union"
+    , "$1":
+      [ {"type": "singleton_map", "key": "PATH", "value": "/bin:/usr/bin"}
+      , {"type": "var", "name": "ENV", "default": {"type": "empty_map"}}
+      ]
+    }
+  }
+, "stage_singleton_field":
+  { "vars": ["fieldname", "transition", "location"]
+  , "expression":
+    { "type": "disjoint_map_union"
+    , "$1":
+      { "type": "foreach"
+      , "var": "src"
+      , "range":
+        {"type": "FIELD", "name": {"type": "var", "name": "fieldname"}}
+      , "body":
+        { "type": "disjoint_map_union"
+        , "$1":
+          { "type": "foreach"
+          , "var": "artifact"
+          , "range":
+            { "type": "values"
+            , "$1":
+              { "type": "DEP_ARTIFACTS"
+              , "dep": {"type": "var", "name": "src"}
+              , "transition":
+                { "type": "var"
+                , "name": "transition"
+                , "default": {"type": "empty_map"}
+                }
+              }
+            }
+          , "body":
+            { "type": "singleton_map"
+            , "key": {"type": "var", "name": "location"}
+            , "value": {"type": "var", "name": "artifact"}
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/data/RULES b/data/RULES
new file mode 100644
index 0000000..34bc624
--- /dev/null
+++ b/data/RULES
@@ -0,0 +1,42 @@
+{ "staged":
+  { "doc": ["Stage data to a logical subdirectory."]
+  , "target_fields": ["srcs"]
+  , "string_fields": ["stage"]
+  , "field_doc":
+    { "srcs": ["The (run)files to be staged"]
+    , "stage":
+      [ "The logical directory to stage the files to."
+      , "Individual directory components are joined with \"/\"."
+      ]
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "srcs"
+        , { "type": "disjoint_map_union"
+          , "$1":
+            { "type": "foreach"
+            , "var": "x"
+            , "range": {"type": "FIELD", "name": "srcs"}
+            , "body":
+              {"type": "DEP_RUNFILES", "dep": {"type": "var", "name": "x"}}
+            }
+          }
+        ]
+      , [ "staged"
+        , { "type": "to_subdir"
+          , "subdir": {"type": "var", "name": "stage"}
+          , "$1": {"type": "var", "name": "srcs"}
+          }
+        ]
+      ]
+    , "body": {"type": "RESULT", "runfiles": {"type": "var", "name": "staged"}}
+    }
+  }
+}
diff --git a/proto/RULES b/proto/RULES
new file mode 100644
index 0000000..b6ce000
--- /dev/null
+++ b/proto/RULES
@@ -0,0 +1,105 @@
+{ "library":
+  { "target_fields": ["srcs", "deps"]
+  , "string_fields": ["stage", "name", "service"]
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ [ "stage"
+        , { "type": "join"
+          , "separator": "/"
+          , "$1": {"type": "FIELD", "name": "stage"}
+          }
+        ]
+      , [ "name"
+        , { "type": "assert_non_empty"
+          , "msg": "Have to provide a name, unique in the stage"
+          , "$1": {"type": "join", "$1": {"type": "FIELD", "name": "name"}}
+          }
+        ]
+      , [ "srcs"
+        , [ { "type": "VALUE_NODE"
+            , "$1":
+              { "type": "RESULT"
+              , "artifacts":
+                { "type": "to_subdir"
+                , "subdir": {"type": "var", "name": "stage"}
+                , "$1":
+                  { "type": "disjoint_map_union"
+                  , "msg": "Sources have to be conflict free"
+                  , "$1":
+                    { "type": "foreach"
+                    , "var": "x"
+                    , "range": {"type": "FIELD", "name": "srcs"}
+                    , "body":
+                      { "type": "DEP_ARTIFACTS"
+                      , "dep": {"type": "var", "name": "x"}
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          ]
+        ]
+      , [ "deps"
+        , { "type": "++"
+          , "$1":
+            { "type": "foreach"
+            , "var": "x"
+            , "range": {"type": "FIELD", "name": "deps"}
+            , "body":
+              { "type": "DEP_PROVIDES"
+              , "dep": {"type": "var", "name": "x"}
+              , "provider": "proto"
+              }
+            }
+          }
+        ]
+      , [ "node"
+        , { "type": "ABSTRACT_NODE"
+          , "node_type":
+            { "type": "if"
+            , "cond": {"type": "FIELD", "name": "service"}
+            , "then": "service library"
+            , "else": "library"
+            }
+          , "target_fields":
+            { "type": "map_union"
+            , "$1":
+              [ { "type": "singleton_map"
+                , "key": "srcs"
+                , "value": {"type": "var", "name": "srcs"}
+                }
+              , { "type": "singleton_map"
+                , "key": "deps"
+                , "value": {"type": "var", "name": "deps"}
+                }
+              ]
+            }
+          , "string_fields":
+            { "type": "map_union"
+            , "$1":
+              [ { "type": "singleton_map"
+                , "key": "name"
+                , "value": [{"type": "var", "name": "name"}]
+                }
+              , { "type": "singleton_map"
+                , "key": "stage"
+                , "value": [{"type": "var", "name": "stage"}]
+                }
+              ]
+            }
+          }
+        ]
+      ]
+    , "body":
+      { "type": "RESULT"
+      , "provides":
+        { "type": "singleton_map"
+        , "key": "proto"
+        , "value": [{"type": "var", "name": "node"}]
+        }
+      }
+    }
+  }
+}
diff --git a/transitions/EXPRESSIONS b/transitions/EXPRESSIONS
new file mode 100644
index 0000000..8ea7550
--- /dev/null
+++ b/transitions/EXPRESSIONS
@@ -0,0 +1,13 @@
+{ "for host":
+  { "vars": ["ARCH", "HOST_ARCH"]
+  , "expression":
+    { "type": "singleton_map"
+    , "key": "TARGET_ARCH"
+    , "value":
+      { "type": "var"
+      , "name": "HOST_ARCH"
+      , "default": {"type": "var", "name": "ARCH"}
+      }
+    }
+  }
+}