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mirror of https://github.com/github/semantic.git synced 2024-12-21 13:51:44 +03:00
semantic/src/Syntax.hs
2016-06-29 11:23:11 -04:00

21 lines
1.2 KiB
Haskell

module Syntax where
import Prologue
import Data.OrderedMap
import qualified Data.Text as T
-- | A node in an abstract syntax tree.
data Syntax
a -- ^ The type of leaves in the syntax tree, typically String, but possibly some datatype representing different leaves more precisely.
f -- ^ The type representing another level of the tree, e.g. the children of branches. Often Cofree or Fix or similar.
=
-- | A terminal syntax node, e.g. an identifier, or atomic literal.
Leaf a
-- | An ordered branch of child nodes, expected to be variadic in the grammar, e.g. a list of statements or uncurried function parameters.
| Indexed [f]
-- | An ordered branch of child nodes, expected to be of fixed length in the grammar, e.g. a binary operator & its operands.
| Fixed [f]
-- | A branch of child nodes indexed by some String identity. This is useful for identifying e.g. methods & properties in a class scope by their names. Note that comments can generally occur in these scopes as well; one strategy for dealing with this is to identify comments by their text in the source.
| Keyed (OrderedMap T.Text f)
deriving (Eq, Foldable, Functor, Ord, Show, Traversable)