commit 2adfe1e78c53e130e138f0d44f894d5a0edfad46
parent 4039f027a606a2a044a862a610eca7e4dc934020
Author: Robert Russell <robert@rr3.xyz>
Date: Tue, 27 Aug 2024 00:01:46 -0700
Delete lex{,M}
It's cool, but unnecessary once you have bytesOf. Maybe it's still
worthwhile to have a state machine-like parser combinator; we'll
see if we ever end up wanting it.
Diffstat:
| M | Sparsec.hs | | | 36 | ------------------------------------ |
1 file changed, 0 insertions(+), 36 deletions(-)
diff --git a/Sparsec.hs b/Sparsec.hs
@@ -355,39 +355,3 @@ natural = \case
numeral >>= iter (\n -> (nat b * n +) <$> (underscores *> numeral))
_ -> error "natural: invalid base"
-
-data LexAction e t s
- = LexFail
- | LexError e
- | LexRejectEmit t -- Reject rune and emit token.
- | LexAcceptCont s -- Accept rune and continue lexing in the given state.
-
--- TODO: Delete this.
--- lexM (and it's non-monadic counterpart lex) lexes a token (of some type t)
--- in the manner of an automaton. That is, given a start state (of some type
--- s) and a transition function that maps (s, Rune) pairs to "actions", lexM
--- tracks the current state and repeatedly calls the transition function with
--- runes from the input until it returns an action indicating it should stop.
-lexM :: forall m e t s. (Utf8Error e, Monad m)
- => s
- -> ((s, Rune) -> m (LexAction e t s))
- -> ParseT e m (ByteString, t)
-lexM startState trans = do
- (input, beg) <- save
- let gobble :: s -> ParseT e m t
- gobble s = do
- r <- lookahead nextRune
- (lift $ trans (s, r)) >>= \case
- LexFail -> fail
- LexError e -> err e
- LexRejectEmit t -> pure t
- LexAcceptCont s -> nextRune *> gobble s
- t <- gobble startState
- end <- getLoc
- pure (ByteString.take (end.byte - beg.byte) input, t)
-
-lex :: (Utf8Error e, Monad m)
- => s
- -> ((s, Rune) -> LexAction e t s)
- -> ParseT e m (ByteString, t)
-lex startState trans = lexM startState (pure . trans)
