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bef7a44fa8
Summary: . Reviewed By: JonCoens Differential Revision: D6838082 fbshipit-source-id: 94757bdb80c6d3c29a7a6554429940a1b7403108
229 lines
7.8 KiB
Haskell
229 lines
7.8 KiB
Haskell
-- Copyright (c) 2016-present, Facebook, Inc.
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-- All rights reserved.
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--
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-- This source code is licensed under the BSD-style license found in the
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-- LICENSE file in the root directory of this source tree. An additional grant
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-- of patent rights can be found in the PATENTS file in the same directory.
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{-# LANGUAGE GADTs #-}
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{-# LANGUAGE NamedFieldPuns #-}
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{-# LANGUAGE NoRebindableSyntax #-}
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module Duckling.Engine
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( parseAndResolve
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, lookupRegexAnywhere
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, runDuckling
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) where
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import Control.DeepSeq
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import Control.Monad.Extra
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import Data.Aeson
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import Data.ByteString (ByteString)
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import Data.Functor.Identity
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import Data.Maybe
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import Data.Text (Text)
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import Prelude
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import qualified Data.Array as Array
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import qualified Data.Foldable as Foldable
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import qualified Data.List as L
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import qualified Text.Regex.PCRE as PCRE
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import Duckling.Dimensions.Types
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import Duckling.Regex.Types
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import Duckling.Resolve
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import Duckling.Types
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import Duckling.Types.Document (Document)
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import Duckling.Types.Stash (Stash)
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import qualified Duckling.Engine.Regex as Regex
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import qualified Duckling.Types.Document as Document
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import qualified Duckling.Types.Stash as Stash
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-- -----------------------------------------------------------------
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-- Engine
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type Duckling a = Identity a
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runDuckling :: Duckling a -> a
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runDuckling ma = runIdentity ma
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parseAndResolve :: [Rule] -> Text -> Context -> [ResolvedToken]
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parseAndResolve rules input context = mapMaybe (resolveNode context) .
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force $ Stash.toPosOrderedList $ runDuckling $
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parseString rules (Document.fromText input)
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produce :: Match -> Maybe Node
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produce (_, _, []) = Nothing
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produce (Rule name _ production, _, etuor@(Node {nodeRange = Range _ e}:_)) = do
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let route = reverse etuor
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token <- force $ production $ map token route
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case route of
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(Node {nodeRange = Range p _}:_) -> Just Node
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{ nodeRange = Range p e
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, token = token
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, children = route
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, rule = Just name
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}
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[] -> Nothing
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-- | Handle a regex match at a given position
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lookupRegex :: Document -> PCRE.Regex -> Int -> Duckling [Node]
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lookupRegex doc _regex position | position >= Document.length doc = return []
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lookupRegex doc regex position =
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lookupRegexCommon doc regex position Regex.matchOnce
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-- | Handle a regex match anywhere in the text
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lookupRegexAnywhere :: Document -> PCRE.Regex -> Duckling [Node]
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lookupRegexAnywhere doc regex = lookupRegexCommon doc regex 0 Regex.matchAll
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{-# INLINE lookupRegexCommon #-}
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-- INLINE bloats the code a bit, but the code is better
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lookupRegexCommon
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:: Foldable t
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=> Document
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-> PCRE.Regex
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-> Int
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-> (PCRE.Regex -> ByteString -> t PCRE.MatchArray)
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-> Duckling [Node]
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lookupRegexCommon doc regex position matchFun = return nodes
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where
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-- See Note [Regular expressions and Text] to understand what's going
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-- on here
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(substring, rangeToText, translateRange) =
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Document.byteStringFromPos doc position
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nodes = mapMaybe (f . Array.elems) $ Foldable.toList $
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matchFun regex substring
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f :: [(Int, Int)] -> Maybe Node
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f [] = Nothing
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f ((0,0):_) = Nothing
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f ((bsStart, bsLen):groups) =
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if Document.isRangeValid doc start end
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then Just node
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else Nothing
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where
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textGroups = map rangeToText groups
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(start, end) = translateRange bsStart bsLen
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node = Node
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{ nodeRange = Range start end
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, token = Token RegexMatch (GroupMatch textGroups)
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, children = []
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, rule = Nothing
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}
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-- | Handle one PatternItem at a given position
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lookupItem :: Document -> PatternItem -> Stash -> Int -> Duckling [Node]
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lookupItem doc (Regex re) _ position =
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filter (isPositionValid position doc) <$>
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lookupRegex doc re position
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lookupItem doc (Predicate p) stash position =
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return $
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filter (p . token) $
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takeWhile (isPositionValid position doc) $
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Stash.toPosOrderedListFrom stash position
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-- | Handle one PatternItem anywhere in the text
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lookupItemAnywhere :: Document -> PatternItem -> Stash -> Duckling [Node]
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lookupItemAnywhere doc (Regex re) _ = lookupRegexAnywhere doc re
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lookupItemAnywhere _doc (Predicate p) stash =
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return $ filter (p . token) $ Stash.toPosOrderedList stash
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isPositionValid :: Int -> Document -> Node -> Bool
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isPositionValid position sentence Node{nodeRange = Range start _} =
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Document.isAdjacent sentence position start
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-- | A match is full if its rule pattern is empty.
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-- (rule, endPosition, reversedRoute)
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type Match = (Rule, Int, [Node])
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-- | Recursively augments `matches`.
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-- Discards partial matches stuck by a regex.
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matchAll :: Document -> Stash -> [Match] -> Duckling [Match]
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matchAll sentence stash matches = concatMapM mkNextMatches matches
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where
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mkNextMatches :: Match -> Duckling [Match]
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mkNextMatches match@(Rule {pattern = []}, _, _) = return [ match ]
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mkNextMatches match@(Rule {pattern = p:_}, _, _) = do
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nextMatches <- matchAll sentence stash =<< matchFirst sentence stash match
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return $ case p of
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Regex _ -> nextMatches
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Predicate _ -> match:nextMatches
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-- | Returns all matches matching the first pattern item of `match`,
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-- resuming from a Match position
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matchFirst :: Document -> Stash -> Match -> Duckling [Match]
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matchFirst _ _ (Rule {pattern = []}, _, _) = return []
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matchFirst sentence stash (rule@Rule{pattern = p : ps}, position, route) =
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map (mkMatch route newRule) <$> lookupItem sentence p stash position
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where
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newRule = rule { pattern = ps }
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-- | Returns all matches matching the first pattern item of `match`,
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-- starting anywhere
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matchFirstAnywhere :: Document -> Stash -> Rule -> Duckling [Match]
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matchFirstAnywhere _sentence _stash Rule {pattern = []} = return []
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matchFirstAnywhere sentence stash rule@Rule{pattern = p : ps} =
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map (mkMatch [] newRule) <$> lookupItemAnywhere sentence p stash
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where
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newRule = rule { pattern = ps }
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{-# INLINE mkMatch #-}
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mkMatch :: [Node] -> Rule -> Node -> Match
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mkMatch route newRule (node@Node {nodeRange = Range _ pos'}) =
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newRoute `seq` (newRule, pos', newRoute)
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where newRoute = node:route
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-- | Finds new matches resulting from newly added tokens.
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-- Produces new tokens from full matches.
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parseString1
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:: [Rule] -> Document -> Stash -> Stash -> [Match]
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-> Duckling (Stash, [Match])
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parseString1 rules sentence stash new matches = do
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-- Recursively match patterns.
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-- Find which `matches` can advance because of `new`.
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newPartial <- concatMapM (matchFirst sentence new) matches
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-- Find new matches resulting from newly added tokens (`new`)
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newMatches <- concatMapM (matchFirstAnywhere sentence new) rules
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(full, partial) <- L.partition (\(Rule {pattern}, _, _) -> null pattern)
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<$> matchAll sentence stash (newPartial ++ newMatches)
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-- Produce full matches as new tokens
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return ( Stash.fromList $ mapMaybe produce full
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, partial ++ matches
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)
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-- | Produces all tokens recursively.
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saturateParseString
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:: [Rule] -> Document -> Stash -> Stash -> [Match] -> Duckling Stash
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saturateParseString rules sentence stash new matches = do
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(new', matches') <- parseString1 rules sentence stash new matches
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let stash' = Stash.union stash new'
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if Stash.null new'
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then return stash
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else saturateParseString rules sentence stash' new' matches'
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parseString :: [Rule] -> Document -> Duckling Stash
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parseString rules sentence = do
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(new, partialMatches) <-
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-- One the first pass we try all the rules
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parseString1 rules sentence Stash.empty Stash.empty []
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if Stash.null new
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then return Stash.empty
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else
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-- For subsequent passes, we only try rules starting with a predicate.
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saturateParseString headPredicateRules sentence new new partialMatches
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where
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headPredicateRules =
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[ rule | rule@Rule{pattern = (Predicate _ : _)} <- rules ]
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resolveNode :: Context -> Node -> Maybe ResolvedToken
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resolveNode context n@Node{token = (Token _ dd), nodeRange = nodeRange} = do
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val <- resolve context dd
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Just Resolved
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{ range = nodeRange
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, node = n
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, jsonValue = toJSON val
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}
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