Parse macro definitions with arguments

cruessler · Feb 18, 2024 · 01cb5a5 · 01cb5a5
1 parent 9c51a1b
commit 01cb5a5
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diff --git a/app/elm/Compiler/Ast.elm b/app/elm/Compiler/Ast.elm
@@ -3,6 +3,7 @@ module Compiler.Ast exposing
     , CompiledProgram
     , Context(..)
     , Function
+    , Macro
     , Node(..)
     , Program
     , compile
@@ -45,6 +46,13 @@ type alias Function =
     }
 
 
+type alias Macro =
+    { name : String
+    , requiredArguments : List String
+    , body : List Node
+    }
+
+
 {-| Represent a compiled function.
 -}
 type alias CompiledFunction =

diff --git a/app/elm/Compiler/Parser.elm b/app/elm/Compiler/Parser.elm
@@ -6,6 +6,7 @@ module Compiler.Parser exposing
     , booleanExpression
     , defaultState
     , functionDefinition
+    , macroDefinition
     , output
     , statement
     , term
@@ -235,6 +236,37 @@ functionBody_ state acc =
         ]
 
 
+defineMacro : State -> Ast.Macro -> Parser Ast.Macro
+defineMacro state newMacro =
+    functionBody state
+        |> P.map (\body -> { newMacro | body = body })
+
+
+macroDefinition : State -> Parser Ast.Macro
+macroDefinition state =
+    P.inContext MacroDefinition <|
+        (macroHeader
+            |> P.andThen (defineMacro state)
+        )
+
+
+macroHeader : Parser Ast.Macro
+macroHeader =
+    P.succeed Ast.Macro
+        |. Helper.keyword ".macro"
+        |. Helper.spaces
+        |= Helper.functionName
+        |= P.oneOf
+            [ P.succeed identity
+                |. P.backtrackable Helper.spaces
+                |= requiredArguments
+            , P.succeed []
+            ]
+        |. Helper.maybeSpaces
+        |. Helper.symbol "\n"
+        |= P.succeed []
+
+
 line : State -> Parser (List Ast.Node)
 line state =
     P.inContext Line <|

diff --git a/app/elm/Compiler/Parser/Context.elm b/app/elm/Compiler/Parser/Context.elm
@@ -6,6 +6,7 @@ type Context
     | Toplevel
     | FunctionDefinition
     | FunctionBody
+    | MacroDefinition
     | Line
     | Statements
     | Statement

diff --git a/tests/Test/Parser.elm b/tests/Test/Parser.elm
@@ -119,6 +119,46 @@ functionDefinition =
         ]
 
 
+parsesMacro : String -> Ast.Macro -> Expectation
+parsesMacro source macro =
+    let
+        result =
+            Parser.run (Parser.macroDefinition defaultState) source
+    in
+    Expect.equal result (Ok macro)
+
+
+macroDefinition : Test
+macroDefinition =
+    describe "define a macro" <|
+        [ test "with mandatory arguments and no body" <|
+            \_ ->
+                parsesMacro ".macro foo :bar :baz\nend\n"
+                    { name = "foo"
+                    , requiredArguments = [ "bar", "baz" ]
+                    , body = []
+                    }
+        , test "with mandatory argument and body" <|
+            \_ ->
+                parsesMacro ".macro foo :bar\nprint :bar\nend\n"
+                    { name = "foo"
+                    , requiredArguments = [ "bar" ]
+                    , body =
+                        [ Ast.CommandN
+                            { name = "print", f = C.printN, numberOfDefaultArguments = 1 }
+                            [ Ast.Variable "bar" ]
+                        ]
+                    }
+        , test "without arguments" <|
+            \_ ->
+                parsesMacro ".macro foo\nend\n"
+                    { name = "foo"
+                    , requiredArguments = []
+                    , body = []
+                    }
+        ]
+
+
 parsesArithmeticExpression : String -> Test
 parsesArithmeticExpression expression =
     let