Add lput

app/elm/Compiler/Ast/Primitive.elm

@@ -43,6 +43,7 @@ all =
     , Primitive2 { name = "less?", f = P.lessp }
     , Primitive2 { name = "remainder", f = P.remainder }
     , Primitive2 { name = "fput", f = P.fput }
+    , Primitive2 { name = "lput", f = P.lput }
     , PrimitiveN { name = "array", f = P.array, numberOfDefaultArguments = 1 }
     , PrimitiveN { name = "sentence", f = P.sentence, numberOfDefaultArguments = 2 }
     , PrimitiveN { name = "se", f = P.sentence, numberOfDefaultArguments = 2 }

app/elm/Vm/Primitive.elm

@@ -22,6 +22,7 @@ module Vm.Primitive exposing
     , integerp
     , lessp
     , listp
+    , lput
     , lshift
     , minus
     , notequalp
@@ -613,6 +614,32 @@ fput value1 value2 =
                 Err <| WrongInput "fput" word_
 
 
+{-|
+
+> outputs a list equal to its second input with one extra member, the first
+> input, at the end. If the second input is a word, then the first input must
+> be a one-letter word, and LPUT is equivalent to WORD with its inputs in the
+> other order.
+
+-}
+lput : Type.Value -> Type.Value -> Result Error Type.Value
+lput value1 value2 =
+    case ( value1, value2 ) of
+        ( _, Type.List list ) ->
+            Ok <| Type.List <| list ++ [ value1 ]
+
+        _ ->
+            let
+                word_ =
+                    Type.toString value1
+            in
+            if String.length word_ == 1 then
+                Ok <| Type.Word <| Type.toString value2 ++ word_
+
+            else
+                Err <| WrongInput "lput" word_
+
+
 {-|
 
 > outputs an array of "size" members (must be a positive integer), each of which

tests/Test/Primitive.elm

@@ -210,6 +210,18 @@ primitives =
                         (P.fput (T.Word "wo") (T.Word "rd"))
                         (Err <| Error.WrongInput "fput" "wo")
             ]
+        , describe "lput"
+            [ test "works with 2 strings" <|
+                \_ ->
+                    Expect.equal
+                        (P.lput (T.Word "w") (T.List [ T.Word "o" ]))
+                        (Ok <| T.List [ T.Word "o", T.Word "w" ])
+            , test "fails with 2 words if first word has more than one character" <|
+                \_ ->
+                    Expect.equal
+                        (P.lput (T.Word "wo") (T.Word "rd"))
+                        (Err <| Error.WrongInput "lput" "wo")
+            ]
         , describe "bitand"
             [ test "works with 2 integers" <|
                 \_ ->

tests/Test/Run/Builtin.elm

@@ -142,6 +142,10 @@ primitives =
             [ printsLine "print fput \"w \"ord" "word"
             , printsLine "print fput \"w [ o r d ]" "w o r d"
             ]
+        , describe "lput" <|
+            [ printsLine "print lput \"w \"ord" "ordw"
+            , printsLine "print lput \"w [ o r d ]" "o r d w"
+            ]
         ]