module MyElm.Syntax exposing ( QualifiedName, local, valueName, typeName, constructorName , Expression, string, float, int, list, pair, triple, call0, call1, call2, call3, call4, calln, pipe, record , Type, type0, type1, type2, typen, recordType, functionType, pairType, tripleType, typeVar , Declaration, variable, fun1, customType, typeAlias , build, Exposing, opaque, withConstructors, exposeFn ) {-| This module is intended for autogenerating elm code with relatively minimal fuss and without needing to do bookkeeping about minor details like indentation, etc. This is meant as the simple, convenient module that you should get started with. It attempts to reduce boilerplate to a minimum, but makes some opinionated choice about what the results should look like. You can also use the Advanced module if you want to make different choices. The simplifcations made here are: - Helpers for naming things assume a particular import style. - Imports are generated for you automatically. - Custom types and type alaises generate their type variables implicitely. ### Naming things @docs QualifiedName, local, valueName, typeName, constructorName ### Expressions @docs Expression, string, float, int, list, pair, triple, call0, call1, call2, call3, call4, calln, pipe, record ### Type signatures @docs Type, type0, type1, type2, typen, recordType, functionType, pairType, tripleType, typeVar ### Declarations @docs Declaration, variable, fun1, customType, typeAlias ### Modules @docs build, Exposing, opaque, withConstructors, exposeFn -} import MyElm.Stringify import MyElm.Types exposing (..) import Set {-| The simplest thing you will need to do is keep track of what things in the program are called and where they come from. -} type alias QualifiedName = MyElm.Types.QualifiedName {-| This is a value (i.e. variable or function, but not type or constructor) from a module whose path is the first argument. -} valueName : List String -> String -> QualifiedName valueName modulePath name = FullyQualified modulePath (ValueOrType name) {-| This is a type from a module whose path is the first argument. -} typeName : List String -> String -> QualifiedName typeName modulePath name = Bare modulePath (ValueOrType name) {-| This is a constructor for a type (the second argument) from a module whose path is the first argument. just = constructorName [ "Result" ] "Result" "Just" -} constructorName : List String -> String -> String -> QualifiedName constructorName modulePath typeNm name = Bare modulePath (Constructor typeNm name) {-| This is a variable local to the module you are generating. -} local : String -> QualifiedName local name = Local (ValueOrType name) isLocal : QualifiedName -> Bool isLocal qualifiedName = case qualifiedName of Local _ -> True _ -> False {-| Create a module and return it as a pretty printed string. -} build : { name : List String , exposes : List Exposing , doc : Maybe String , declarations : List Declaration } -> String build m = Module { name = String.join "." m.name , exposes = m.exposes , doc = m.doc , imports = consolidateImports (extractImports m.declarations) , declarations = m.declarations } |> MyElm.Stringify.module2string {-| What you would like to expose from a module. -} type alias Exposing = MyElm.Types.Exposing {-| Expose a custom type, but leave the constructors hidden. -} opaque : String -> Exposing opaque = TypeExposed {-| Expose a custom type and all its constructors. -} withConstructors : String -> Exposing withConstructors = TypeAndConstructors {-| Expose a function or value. -} exposeFn : String -> Exposing exposeFn = ValueExposed {-| -} type alias Declaration = MyElm.Types.Declaration {-| This will do automatic type variable extraction for you in order of appearance in the type declaration. So for example: customType "Foo" [ ( "Bar", TypeVariable "g" ) , ( "Baz", TypeVariable "comparable" ) ] would generate the following code: type Foo g comparable = Bar g | Baz comparable If you would like to control the order in which type variables appear, you can use the function in the "Advanced" module. -} customType : String -> List ( String, List Type ) -> Declaration customType name variants = CustomType name (List.concatMap (Tuple.second >> List.concatMap extractVariables) variants |> unique) variants {-| Declare a type alias. Also does automatic type variable extraction. -} typeAlias : String -> Type -> Declaration typeAlias name type_ = TypeAlias name (extractVariables type_ |> unique) type_ unique : List comparable -> List comparable unique = Set.fromList >> Set.toList extractVariables : Type -> List String extractVariables tp = case tp of NamedType _ typeList -> List.concatMap extractVariables typeList RecordType branches -> List.concatMap (Tuple.second >> extractVariables) branches FunctionType typeList -> List.concatMap extractVariables typeList TupleType typeList -> List.concatMap extractVariables typeList TypeVariable variable_ -> [ variable_ ] {-| Declare a top level variable. -} variable : String -> Type -> Expression -> Declaration variable name typeAnno expression = ValueDeclaration name [ typeAnno ] [] expression {-| Declare a top level function with a single argument. fun1 "identity" (typeVar "a") (typeVar "a") "a" call0 would be turned into: identity : a -> a identity a = a -} fun1 : String -> Type -> Type -> String -> (QualifiedName -> Expression) -> Declaration fun1 name fromTp toTp arg f = ValueDeclaration name [ fromTp, toTp ] [ Argument arg ] (f (local arg)) {-| The heart of an elm program are the expressions that implement the computations. -} type alias Expression = MyElm.Types.Expression {-| Reference a variable by name. -} call0 : QualifiedName -> Expression call0 name = Call name [] {-| Call a function with 1 argument. -} call1 : QualifiedName -> Expression -> Expression call1 name arg = Call name [ arg ] {-| Call a function with 2 arguments. -} call2 : QualifiedName -> Expression -> Expression -> Expression call2 name arg1 arg2 = Call name [ arg1, arg2 ] {-| Call a function with 3 arguments. -} call3 : QualifiedName -> Expression -> Expression -> Expression -> Expression call3 name arg1 arg2 arg3 = Call name [ arg1, arg2, arg3 ] {-| Call a function with 4 arguments. -} call4 : QualifiedName -> Expression -> Expression -> Expression -> Expression -> Expression call4 name arg1 arg2 arg3 arg4 = Call name [ arg1, arg2, arg3, arg4 ] {-| Call a function with any number of arguments. -} calln : QualifiedName -> List Expression -> Expression calln name args = Call name args {-| A convenience helper for construcing pipelines. string "foo" |> pipe (valueName [ "String" ] "concat") [ string "bar" ] would generate: "foo" |> String.concat "bar" This is just a helper for: pipe name args subject = call2 (valueName [ "Basics" ] "|>") subject (calln name args) -} pipe : QualifiedName -> List Expression -> Expression -> Expression pipe name args subject = Call (valueName [ "Basics" ] "|>") [ subject, Call name args ] {-| A string literal. -} string : String -> Expression string s = Literal ("\"" ++ String.replace "\"" "\\\"" s ++ "\"") {-| A float literal. -} float : Float -> Expression float f = Literal (String.fromFloat f) {-| An integer literal. -} int : Int -> Expression int i = Literal (String.fromInt i) {-| A list literal -} list : List Expression -> Expression list = ListExpr {-| A two-tuple literal -} pair : Expression -> Expression -> Expression pair a b = Tuple [ a, b ] {-| A three-tuple literal -} triple : Expression -> Expression -> Expression -> Expression triple a b c = Tuple [ a, b, c ] {-| A record literal expression. -} record : List ( String, Expression ) -> Expression record = Record {-| A representation of a type as in a type annotation context. -} type alias Type = MyElm.Types.Type {-| A simple type, like `Int`. -} type0 : QualifiedName -> Type type0 qualifiedName = NamedType qualifiedName [] {-| A type with one argument, like `List`. -} type1 : QualifiedName -> Type -> Type type1 qualifiedName arg1 = NamedType qualifiedName [ arg1 ] {-| A type with 2 arguments. -} type2 : QualifiedName -> Type -> Type -> Type type2 qualifiedName arg1 arg2 = NamedType qualifiedName [ arg1, arg2 ] {-| A type with many arguments. -} typen : QualifiedName -> List Type -> Type typen qualifiedName args = NamedType qualifiedName args {-| A record type. For example we could model { foo = Int , bar = List String } so: recordType [ ( "foo", type0 (typeName [ "Basics" ] "Int") ) , ( "bar" , type1 (typeName [ "Basics" ] "List") (type0 (typeName [ "String" ] "String") ) ) ] -} recordType : List ( String, Type ) -> Type recordType = RecordType {-| A function type. -} functionType : List Type -> Type functionType = FunctionType {-| Pair type. -} pairType : Type -> Type -> Type pairType a b = TupleType [ a, b ] {-| -} tripleType : Type -> Type -> Type -> Type tripleType a b c = TupleType [ a, b, c ] {-| A type variable. -} typeVar : String -> Type typeVar = TypeVariable extractImports : List Declaration -> List QualifiedName extractImports = List.concatMap (\dec -> case dec of CustomType _ _ variants -> List.concatMap (\( _, args ) -> List.concatMap typeImports args) variants TypeAlias _ _ aliased -> typeImports aliased Comment _ -> [] ValueDeclaration _ signature _ expression -> List.concatMap typeImports signature ++ expressionImports expression ) typeImports : Type -> List QualifiedName typeImports tp = case tp of NamedType qualifiedName args -> qualifiedName :: List.concatMap typeImports args RecordType rec -> List.concatMap (\( _, typ ) -> typeImports typ) rec FunctionType typeList -> List.concatMap typeImports typeList TupleType typeList -> List.concatMap typeImports typeList TypeVariable _ -> [] expressionImports : Expression -> List QualifiedName expressionImports expression = case expression of Call qualifiedName expressionList -> qualifiedName :: List.concatMap expressionImports expressionList Literal _ -> [] ListExpr expressionList -> List.concatMap expressionImports expressionList Tuple expressionList -> List.concatMap expressionImports expressionList Record branches -> List.concatMap (Tuple.second >> expressionImports) branches consolidateImports : List QualifiedName -> List String consolidateImports qualifiedNames = qualifiedNames |> List.filter removeDefaults |> List.map toTupleRep |> Set.fromList |> Set.toList |> List.sort |> consolidateTuples |> List.map (\( mod, al, imps ) -> let name = "import " ++ mod alias_ = if al == "" then "" else " as " ++ al exposingList = if List.length imps > 0 then " exposing (" ++ String.join ", " imps ++ ")" else "" in String.join "" [ name, alias_, exposingList ] ) consolidateTuples : List ( String, String, List String ) -> List ( String, String, List String ) consolidateTuples tuples = case tuples of ( xm, xa, xl ) :: ( ym, ya, yl ) :: rest -> if xm == ym && (xa == ya || xa == "" || ya == "") then consolidateTuples (( xm , if xa == "" then ya else xa , xl ++ yl ) :: rest ) else ( xm, xa, xl ) :: consolidateTuples (( ym, ya, yl ) :: rest) x -> x iden2str : Ident -> List String iden2str ident = case ident of Constructor tpname _ -> [ tpname ++ "(..)" ] ValueOrType name -> [ name ] toTupleRep : QualifiedName -> ( String, String, List String ) toTupleRep qualifiedName = case qualifiedName of Local _ -> ( "not-possible", "", [] ) FullyQualified module_ id -> ( String.join "." module_, "", [] ) Aliased module_ alias_ id -> ( String.join "." module_, alias_, [] ) Bare module_ id -> ( String.join "." module_, "", iden2str id ) removeDefaults : QualifiedName -> Bool removeDefaults qualifedName = case qualifedName of Local _ -> False FullyQualified module_ id -> case module_ of [ "Basics" ] -> False [ "List" ] -> False [ "Maybe" ] -> False [ "Result" ] -> False [ "String" ] -> False [ "Char" ] -> False [ "Tuple" ] -> False [ "Debug" ] -> False [ "Platform" ] -> False _ -> True Aliased module_ alias_ id -> case ( module_, alias_ ) of ( [ "Platform", "Cmd" ], "Cmd" ) -> False ( [ "Platform", "Sub" ], "Sub" ) -> False _ -> True Bare module_ (Constructor tpname name) -> case ( module_, tpname ) of ( [ "Basics" ], _ ) -> False ( [ "List" ], "List" ) -> False ( [ "Maybe" ], "Maybe" ) -> False ( [ "Result" ], "Result" ) -> False _ -> True Bare module_ (ValueOrType tpname) -> case ( module_, tpname ) of ( [ "Basics" ], _ ) -> False ( [ "List" ], "List" ) -> False ( [ "List" ], "::" ) -> False ( [ "Maybe" ], "Maybe" ) -> False ( [ "Result" ], "Result" ) -> False ( [ "String" ], "String" ) -> False ( [ "Char" ], "Char" ) -> False ( [ "Platform" ], "Program" ) -> False ( [ "Platform", "Cmd" ], "Cmd" ) -> False ( [ "Platform", "Sub" ], "Sub" ) -> False _ -> True