laid out basic closure object

src/types/closure.nim

@@ -0,0 +1,63 @@
+# Copyright 2020 Mattia Giambirtone
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+## Implements closures
+
+import baseObject
+import function
+import ../memory
+
+
+type Closure* = object of Obj
+    ## Represents a function
+    ## closing over values outside
+    ## of its lexical scope
+    function*: ptr Function
+
+
+proc newClosure(function: ptr Function): ptr Closure =
+    ## Initializes a new closure from a function
+    ## object
+    result = allocateObject(Closure, ObjectType.Closure)
+    result.function = function
+
+
+proc typeName*(self: ptr Closure): string =
+    result = "function"
+
+
+proc stringify*(self: ptr Closure): string =
+    if self.function.name != nil:
+        if self.function.name.toStr() == "<lambda function>":
+            result = self.function.name.toStr()
+        else:
+            result = "<function '" & self.function.name.toStr() & "'>"
+    else:
+        result = "<code object>"
+
+
+proc isFalsey*(self: ptr Closure): bool =
+    result = false
+
+
+proc hash*(self: ptr Closure): uint64 =
+    result = uint64(393027534)   # Arbitrary hash because ¯\_(ツ)_/¯
+
+
+proc eq*(self, other: ptr Closure): bool =
+    result = self.function == other.function  # Pointer equality
+
+
+proc eq*(self: ptr Closure, other: ptr Function): bool =
+    result = self.function == other