add let code gen

Author: emptyflash

src/Gen.hs

@@ -0,0 +1,37 @@
+module Gen where
+
+import Infer
+import Syntax
+import Type
+
+
+generateType :: GlslTypes -> String
+generateType ty = case ty of
+    Bool -> "bool"
+    Int -> "int"
+    Float -> "float"
+    Vec2 -> "vec2"
+    Vec3 -> "vec3"
+
+
+generateLet :: TypeEnv -> [Decl] -> Expr -> String -> String
+generateLet env [] inExpr state = state ++ "return " ++ (generateExpr env inExpr) ++ ";\n"
+generateLet env ((var, expr):xs) inExpr state = let
+  typeResult = inferExpr env expr
+  (newEnv, newState) = case typeResult of
+    Left error -> (env, state ++ (show error))
+    Right scheme@(Forall [] (TCon ty)) -> (extend env (var, scheme), state ++ (generateType ty) ++ " " ++ var ++ " = " ++ (generateExpr env expr) ++ ";\n")
+  in generateLet newEnv xs inExpr newState
+
+generateExpr :: TypeEnv -> Expr -> String
+generateExpr env expr = case expr of
+  Var x -> x
+
+  Let decls expr -> generateLet env decls expr ""
+
+  Lit lit -> case lit of
+    LInt int -> show int
+
+    LBool bool -> show bool
+
+    LFloat float -> show float

stack.yaml.lock

@@ -0,0 +1,26 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: megaparsec-7.0.4@sha256:890d317e75151a48567900cdbe39d3c44e83918d79a39ce97b9245cab5402d5e,6222
+    pantry-tree:
+      size: 2647
+      sha256: 550e6fd35a8fde17f7fa005e823ee7a23b5415e73c8d5058825832d256ab5609
+  original:
+    hackage: megaparsec-7.0.4
+- completed:
+    hackage: primitive-0.6.4.0@sha256:5b6a2c3cc70a35aabd4565fcb9bb1dd78fe2814a36e62428a9a1aae8c32441a1,2079
+    pantry-tree:
+      size: 1517
+      sha256: 5d5e591311664886e88ade3da6880c32adf0d1fe80c55f40a3c93bb91df8fdeb
+  original:
+    hackage: primitive-0.6.4.0
+snapshots:
+- completed:
+    size: 506735
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/12/19.yaml
+    sha256: 78de20c2fce471a4c4a19e935e216538e7f0308f6f15ad72aedc5484de45f09b
+  original: lts-12.19

test/Spec.hs

@@ -8,6 +8,7 @@ import Syntax
 import Lexer
 import Infer
 import Type
+import Gen
 
 
 
@@ -94,3 +95,11 @@ main = hspec $ do
             case P.parseModule "std.yin" stdLib of
                 Right a -> True `shouldBe` True
                 Left err -> do { putStrLn $ show err; False `shouldBe` True }
+
+    describe "code generation" $ do
+        
+        it "should generate simple let expr" $ do
+            let expr = (Let [ ("a", Lit $ LInt 1)
+                            , ("b", Var "a")] (Var "b"))
+            let result = generateExpr glslStdLib expr
+            result `shouldBe` "int a = 1;\nint b = a;\nreturn b;\n"