BNFC.Backend.Haskell.Utils

Haskell line comments.

Haskell line comment including mode hint for emacs.

Create a valid parser function name for a given category.

>>> parserName (Cat "Abcd")pAbcd

>>> parserName (ListCat (Cat "Xyz"))pListXyz

Haskell's reserved words.

Avoid Haskell keywords plus additional reserved words.

Modifier to avoid clashes in definition.

Convert a function type to Haskell syntax in curried form.

Render a category from the grammar to a Haskell type.

>>> catToType id empty (Cat "A")A>>> catToType id empty (ListCat (Cat "A"))[A]>>> catToType ("Foo." P.<>) empty (TokenCat "Ident")Foo.Ident

Note that there is no haskell type for coerced categories: they should be normalized: >>> catToType id empty (CoercCat Expr 2) Expr

If a type parameter is given it is added to the type name: >>> catToType id (text "a") (Cat A) (A a)

>>> catToType id (text "a") (ListCat (Cat "A"))[A a]

but not added to Token categories: >>> catToType ("Foo." P.<>) (text "a") (TokenCat Integer) Integer

>>> catToType id (text "a") (ListCat (TokenCat "Integer"))[Integer]

>>> catToType id empty (ListCat (CoercCat "Exp" 2))[Exp]

>>> catToType ("Foo." P.<>) (text "()") (ListCat (CoercCat "Exp" 2))[Foo.Exp ()]

Make a variable name for a category.

Gives a list of variables usable for pattern matching.

Example: Given the rule Aba. S ::= A B A ; with the generated data type data S = Aba A B A from the list of categories on the RHS of the rule [A,B,A], we generate the list [a1,b,a2] to be used in a pattern matching like case s of Aba a1 b a2 -> ... ...

>>> catvars [] [Cat "A", Cat "B", Cat "A"][a1,b,a2]

It should avoid reserved words: >>> catvars ["foo"] [Cat Foo, Cat IF, Cat Case, Cat Type, Cat If] [foo_,if_1,case_,type_,if_2]

It uses a suffix -s to mark lists: >>> catvars [] [Cat A, ListCat (Cat A), ListCat (ListCat (Cat A))] [a,as_,ass]