scmdoc

 1{-# LANGUAGE OverloadedStrings #-}
 2
 3-- | This module implements a 'Formatter' for Scheme variable definition.
 4--
 5-- For example:
 6--
 7-- > (define x 42)
 8module SchemeDoc.Format.Variable (Variable (..), mkVariable) where
 9
10import qualified Data.Text as T
11import SchemeDoc.Format.Types
12import SchemeDoc.Format.Util
13import SchemeDoc.Types
14
15-- | A R7RS Scheme variable definition.
16data Variable = Variable
17    { name :: T.Text
18    -- ^ Identifier, i.e. variable name.
19    , value :: Sexp
20    -- ^ Value assigned to the variable name.
21    }
22    deriving (Eq, Show)
23
24instance Formatable Variable where
25    fmt (Variable internalId _) desc =
26        mkDeclaration internalId desc $ \n ->
27            do
28                component "constant " n
29                fromMkd desc
30                htmlSexp (Id n)
31
32-- | Parses a Scheme definition.
33--
34-- > <definition> → (define <identifier> <expression>)
35mkVariable :: Sexp -> Maybe Variable
36mkVariable (List [Id "define", Id n, expr]) =
37    Just $ Variable n expr
38mkVariable _ = Nothing