Add local

app/elm/Compiler/Ast.elm

@@ -107,6 +107,7 @@ type Node
     | Run Node
     | Make Node Node
     | Localmake Node Node
+    | Local Node
     | Thing Node
     | Variable String
     | Value Type.Value
@@ -234,6 +235,9 @@ typeOfCallee node =
         Localmake _ _ ->
             Command { name = "localmake" }
 
+        Local _ ->
+            Command { name = "local" }
+
         Thing _ ->
             Primitive { name = "thing" }
 
@@ -881,6 +885,12 @@ compile context node =
             ]
                 |> List.concat
 
+        Local name ->
+            [ compileInContext (Expression { caller = "local" }) name
+            , [ Instruction.Local ]
+            ]
+                |> List.concat
+
         Thing name ->
             [ compileInContext (Expression { caller = "thing" }) name
             , [ Instruction.Thing ]

app/elm/Compiler/Parser.elm

@@ -374,6 +374,7 @@ statement state =
             , P.lazy (\_ -> run state)
             , stop
             , localmake state
+            , local state
             , make state
             , templateVariable
             , thing state
@@ -800,6 +801,16 @@ localmake state =
         )
 
 
+local : State -> Parser Ast.Node
+local state =
+    P.inContext Local <|
+        (P.succeed Ast.Local
+            |. Helper.keyword "local"
+            |. Helper.spaces
+            |= booleanExpression state
+        )
+
+
 make : State -> Parser Ast.Node
 make state =
     P.inContext Make <|

app/elm/Compiler/Parser/Context.elm

@@ -17,6 +17,7 @@ type Context
     | InParentheses
     | TemplateVariable
     | Localmake
+    | Local
     | Make
     | Thing
     | Variable

app/elm/Vm/Instruction.elm

@@ -30,6 +30,7 @@ type Instruction
     | LocalVariable String
     | Make
     | Localmake
+    | Local
     | Thing
     | Introspect0 I.Introspect0
     | Introspect1 I.Introspect1

app/elm/Vm/Vm.elm

@@ -124,6 +124,9 @@ encodeInstruction instruction =
                 Localmake ->
                     "Localmake"
 
+                Local ->
+                    "Local"
+
                 Thing ->
                     "Thing"
 
@@ -858,6 +861,27 @@ localmake vm =
             )
 
 
+local : Vm -> Result Error Vm
+local vm =
+    popValue1 vm
+        |> Result.andThen
+            (\( name, newVm ) ->
+                name
+                    |> Type.toWord
+                    |> Result.map
+                        (\word ->
+                            let
+                                newScopes =
+                                    vm.scopes
+                                        |> Scope.local word
+                            in
+                            { newVm | scopes = newScopes }
+                                |> incrementProgramCounter
+                        )
+                    |> Result.mapError (\_ -> WrongInput "local" (Type.toDebugString name))
+            )
+
+
 thing : Vm -> Result Error Vm
 thing vm =
     popValue1 vm
@@ -1134,6 +1158,9 @@ execute instruction vm =
         Localmake ->
             localmake vm
 
+        Local ->
+            local vm
+
         Thing ->
             thing vm
 

tests/Test/Error.elm

@@ -71,6 +71,7 @@ functionsWithInvalidArguments =
         , printsError "print fput \"wo \"rd" "fput doesn’t like wo as input"
         , printsError "make [] 1" "make doesn’t like [] as input"
         , printsError "localmake [] 1" "localmake doesn’t like [] as input"
+        , printsError "local []" "local doesn’t like [] as input"
         ]
 
 
@@ -151,6 +152,11 @@ undefinedVariable =
     describe "prints error if undefined variable is used" <|
         [ printsError "print :variable" "variable has no value"
         , printsError ":variable" "variable has no value"
+        , printsError """to f
+local "v make "v 1 print :v
+end
+f
+print :v""" "v has no value"
         ]
 
 

tests/Test/Run.elm

@@ -278,6 +278,18 @@ foo"""
         ]
 
 
+local : Test
+local =
+    describe "variable defined by local is available in called function" <|
+        [ printsLines
+            """to f :recurse
+ifelse :recurse [ local "v make "v "word f "false ] [ print :v ]
+end
+f "true"""
+            [ "word" ]
+        ]
+
+
 optionalArguments : Test
 optionalArguments =
     describe "define function with default value for optional parameter" <|