{-| Copyright: (c) 2018-2019 Kowainik SPDX-License-Identifier: MPL-2.0 Maintainer: Kowainik This module contains the definition of the 'TomlItem' data type which represents either key-value pair or table name. This data type serves the purpose to be the intermediate representation of parsing a TOML file which will be assembled to TOML AST later. @since 1.2.0.0 -} module Toml.Parser.Item ( TomlItem (..) , Table (..) , setTableName , tomlP ) where import Control.Applicative (liftA2, many) import Control.Applicative.Combinators.NonEmpty (sepEndBy1) import Control.Monad.Combinators (between, sepEndBy) import Data.Foldable (asum) import Data.List.NonEmpty (NonEmpty) import Toml.Parser.Core (Parser, eof, sc, text, try, ()) import Toml.Parser.Key (keyP, tableArrayNameP, tableNameP) import Toml.Parser.Value (anyValueP) import Toml.PrefixTree (Key) import Toml.Type (AnyValue) {- | One item of a TOML file. It could be either: * A name of a table * A name of a table array * Key-value pair * Inline table * Inline array of tables Knowing a list of 'TomlItem's, it's possible to construct 'Toml.Type.TOML.TOML' from this information. -} data TomlItem = TableName !Key | TableArrayName !Key | KeyVal !Key !AnyValue | InlineTable !Key !Table | InlineTableArray !Key !(NonEmpty Table) deriving stock (Show, Eq) {- | Changes name of table to a new one. Works only for 'TableName' and 'TableArrayName' constructors. -} setTableName :: Key -> TomlItem -> TomlItem setTableName new = \case TableName _ -> TableName new TableArrayName _ -> TableArrayName new item -> item {- | Table that contains only @key = val@ pairs. -} newtype Table = Table { unTable :: [(Key, AnyValue)] } deriving stock (Show) deriving newtype (Eq) ---------------------------------------------------------------------------- -- Parser ---------------------------------------------------------------------------- -- | Parser for inline tables. inlineTableP :: Parser Table inlineTableP = fmap Table $ between (text "{") (text "}") $ (liftA2 (,) (keyP <* text "=") anyValueP) `sepEndBy` text "," -- | Parser for inline arrays of tables. inlineTableArrayP :: Parser (NonEmpty Table) inlineTableArrayP = between (text "[") (text "]") $ inlineTableP `sepEndBy1` text "," -- | Parser for a single item in the TOML file. tomlItemP :: Parser TomlItem tomlItemP = asum [ TableName <$> try tableNameP "table name" , TableArrayName <$> tableArrayNameP "array of tables name" , keyValP ] where -- parser for "key = val" pairs; can be one of three forms: -- 1. key = { ... } -- 2. key = [ {...}, {...}, ... ] -- 3. key = ... keyValP :: Parser TomlItem keyValP = do key <- keyP <* text "=" asum [ InlineTable key <$> inlineTableP "inline table" , InlineTableArray key <$> try inlineTableArrayP "inline array of tables" , KeyVal key <$> anyValueP "key-value pair" ] -- | Parser for the full content of the .toml file. tomlP :: Parser [TomlItem] tomlP = sc *> many tomlItemP <* eof