Parse and execute for

app/elm/Compiler/Ast.elm

@@ -66,6 +66,7 @@ type Node
     | Repeat Node (List Node)
     | Until Node (List Node)
     | Foreach Node (List Node)
+    | For String Node Node (List Node)
     | Map Node (List Node)
     | Filter Node (List Node)
     | If Node (List Node)
@@ -161,6 +162,9 @@ typeOfCallee node =
         Foreach _ _ ->
             Command { name = "foreach" }
 
+        For _ _ _ _ ->
+            Command { name = "for" }
+
         Map _ _ ->
             Primitive { name = "map" }
 
@@ -606,6 +610,33 @@ compile context node =
             ]
                 |> List.concat
 
+        For variable start end children ->
+            let
+                compiledStart =
+                    compileInContext (Expression { caller = "for" }) start
+
+                compiledEnd =
+                    compileInContext (Expression { caller = "for" }) end
+
+                compiledChildren =
+                    List.concatMap (compileInContext Statement) children
+            in
+            [ compiledStart
+            , [ StoreVariable variable ]
+            , compiledChildren
+            , [ PushVariable variable ]
+            , compiledEnd
+            , [ Eval2 { name = "greaterp", f = P.greaterp }
+              , JumpIfFalse 6
+              , PushVariable variable
+              , PushValue (Type.Int 1)
+              , Eval2 { name = "+", f = P.sum2 }
+              , StoreVariable variable
+              , Jump (List.length compiledChildren + List.length compiledEnd + 7 |> negate)
+              ]
+            ]
+                |> List.concat
+
         Map iterator children ->
             compileMap iterator children
 

app/elm/Compiler/Parser.elm

@@ -7,6 +7,7 @@ module Compiler.Parser exposing
     , defaultState
     , functionDefinition
     , output
+    , statement
     , term
     , withExistingFunctions
     )
@@ -279,6 +280,7 @@ statement state =
             [ inParentheses state
             , P.lazy (\_ -> ifElse state)
             , P.lazy (\_ -> foreach state)
+            , P.lazy (\_ -> for state)
             , P.lazy (\_ -> map state)
             , P.lazy (\_ -> filter state)
             , P.lazy (\_ -> repeat state)
@@ -395,6 +397,25 @@ foreach state =
     P.lazy (\_ -> controlStructure state { keyword = "foreach", constructor = Ast.Foreach })
 
 
+for : State -> Parser Ast.Node
+for state =
+    P.inContext (Keyword "for") <|
+        P.succeed Ast.For
+            |. Helper.keyword "for"
+            |. Helper.spaces
+            |. Helper.symbol "["
+            |. Helper.maybeSpaces
+            |= Value.rawWordInList
+            |. Helper.spaces
+            |= booleanExpression state
+            |. Helper.spaces
+            |= booleanExpression state
+            |. Helper.maybeSpaces
+            |. Helper.symbol "]"
+            |. Helper.spaces
+            |= instructionList state
+
+
 map : State -> Parser Ast.Node
 map state =
     P.lazy (\_ -> invertedControlStructure state { keyword = "map", constructor = Ast.Map })

app/elm/Compiler/Parser/Value.elm

@@ -1,6 +1,6 @@
 module Compiler.Parser.Value exposing
-    ( value
-    , wordOutsideList
+    ( rawWordInList
+    , value
     )
 
 {-| This module provides functions for parsing Logo values.
@@ -22,7 +22,6 @@ import Parser.Advanced as P
         , map
         , oneOf
         , succeed
-        , symbol
         )
 import Vm.Type as Type
 
@@ -117,8 +116,8 @@ valueInList =
             ]
 
 
-wordInList : Parser context Problem Type.Value
-wordInList =
+rawWordInList : Parser context Problem String
+rawWordInList =
     let
         isWordCharacter : Char -> Bool
         isWordCharacter c =
@@ -136,10 +135,14 @@ wordInList =
                 && (c /= '<')
                 && (c /= '>')
     in
-    ((succeed ()
+    (succeed ()
         |. chompIf isWordCharacter ExpectingStartOfWord
         |. chompWhile isWordCharacter
-     )
-        |> getChompedString
     )
+        |> getChompedString
+
+
+wordInList : Parser context Problem Type.Value
+wordInList =
+    rawWordInList
         |> map Type.Word

tests/Test/Parser.elm

@@ -208,3 +208,31 @@ booleanAlgebra =
         , parsesBooleanExpression "1 <> 1"
         , parsesBooleanExpression "2 * (3 + 1) = (4 + 4) * 7"
         ]
+
+
+parsesStatement : String -> Test
+parsesStatement statement =
+    let
+        match : Result (List (DeadEnd context problem)) Ast.Node -> Expectation
+        match result =
+            case result of
+                Ok _ ->
+                    Expect.pass
+
+                Err _ ->
+                    Expect.fail <| "could not parse statement \"" ++ statement ++ "\""
+    in
+    test statement <|
+        \_ ->
+            match
+                (Parser.run (Parser.statement defaultState) statement)
+
+
+controlStructures : Test
+controlStructures =
+    describe "control structures" <|
+        [ describe "for" <|
+            [ parsesStatement "for [ i 0 10 ] [ print :i ]"
+            , parsesStatement "for [i 0 10] [ print :i ]"
+            ]
+        ]

tests/Test/Run.elm

@@ -79,6 +79,14 @@ foreachWithTemplateVariable =
         ]
 
 
+for : Test
+for =
+    describe "for" <|
+        [ printsLines "for [ i 0 3 ] [ print :i ]" [ "0", "1", "2", "3" ]
+        , printsLines "make \"a 0 make \"b 3 for [ i :a :b ] [ print :i ]" [ "0", "1", "2", "3" ]
+        ]
+
+
 map : Test
 map =
     describe "map" <|

tests/Test/Run/Builtin.elm

@@ -99,10 +99,12 @@ primitives =
         , describe "greaterp" <|
             [ printsLine "print greaterp 1 1" "false"
             , printsLine "print greater? 1 1" "false"
+            , printsLine "print greaterp 2 1" "true"
             ]
         , describe "lessp" <|
             [ printsLine "print lessp 1 1" "false"
             , printsLine "print less? 1 1" "false"
+            , printsLine "print lessp 1 2" "true"
             ]
         , describe "remainder" <|
             [ printsLine "print remainder 1 1" "0" ]