feat[compiler]: Compile to bytecode

src/Language/Scalie/Compiler/Bytecode.hs

@@ -1,16 +1,37 @@
-{-# LANGUAGE Safe #-}
-module Language.Scalie.Compiler.Bytecode (EntryPoint, compile) where
-import Language.Scalie.Ast.Module (Module)
+{-# LANGUAGE Trustworthy #-} -- uses vector operations
+{-# LANGUAGE OverloadedRecordDot #-}
+module Language.Scalie.Compiler.Bytecode (EntryPoint, compile, CompilationError(..)) where
+import Language.Scalie.Ast.Module (Module (definitions))
 import Data.Text (Text)
-import Language.Scalie.Ast.Provenance (Provenance)
+import Language.Scalie.Ast.Provenance (Provenance (value, Provenance, source))
 import Language.Scalie.Ast.Provenance.SourceLocation (SourceLocation)
 import Language.Scalie.Bytecode.Object qualified as Bytecode
 import Data.Kind (Type)
+import Data.Either (Either (Left, Right))
+import Data.Vector qualified as Vector
+import Control.Category ((.))
+import Data.Function (($))
+import Data.Functor ((<$>))
+import Data.Map.Implicit qualified as ImplicitMap
+import Data.Maybe (Maybe(Nothing, Just))
+import Language.Scalie.Ast.Definition (Definition(body, name))
+import Language.Scalie.Ast.Expression (Expression(RawInt))
+import Language.Scalie.Bytecode.Instruction qualified as Instruction
 
 -- | The name of the entrypoint function
 
 type EntryPoint :: Type
 type EntryPoint = Text
 
-compile :: Module (Provenance SourceLocation) -> EntryPoint -> Bytecode.Object
-compile = _
+type CompilationError :: Type
+newtype CompilationError = NameNotFound Text
+
+compile :: Module (Provenance SourceLocation) -> EntryPoint -> Either CompilationError Bytecode.Object
+compile mod entry = let
+  topLevelDefinitions = mod.definitions.value
+  in Bytecode.Object . Vector.fromList <$> case ImplicitMap.lookup entry topLevelDefinitions of
+    Nothing -> Left $ NameNotFound entry
+    Just def -> Right
+      [ (\(RawInt i) -> Instruction.PushInteger i) <$> def.body
+      , Provenance def.name.source (Instruction.ReturnValues 1)
+      ]