sepBy package:streamly-core

Apply two parsers alternately to an input stream. Parsing starts at the first parser and stops at the first parser. The output of the first parser is emiited and the output of the second parser is discarded. It can be used to parse a infix style pattern e.g. p1 p2 p1 . Empty input or single parse of the first parser is accepted. Definitions:

>>> sepBy p1 p2 f = Parser.deintercalate p1 p2 (Fold.catLefts f)

>>> sepBy p1 p2 f = Parser.sepBy1 p1 p2 f <|> Parser.fromEffect (Fold.extractM f)

Examples:

>>> p1 = Parser.takeWhile1 (not . (== '+')) Fold.toList

>>> p2 = Parser.satisfy (== '+')

>>> p = Parser.sepBy p1 p2 Fold.toList

>>> Stream.parse p $ Stream.fromList ""
Right []

>>> Stream.parse p $ Stream.fromList "1"
Right ["1"]

>>> Stream.parse p $ Stream.fromList "1+"
Right ["1"]

>>> Stream.parse p $ Stream.fromList "1+2+3"
Right ["1","2","3"]

Like sepBy but requires at least one successful parse. Definition:

>>> sepBy1 p1 p2 f = Parser.deintercalate1 p1 p2 (Fold.catLefts f)

Examples:

>>> p1 = Parser.takeWhile1 (not . (== '+')) Fold.toList

>>> p2 = Parser.satisfy (== '+')

>>> p = Parser.sepBy1 p1 p2 Fold.toList

>>> Stream.parse p $ Stream.fromList ""
Left (ParseError "takeWhile1: end of input")

>>> Stream.parse p $ Stream.fromList "1"
Right ["1"]

>>> Stream.parse p $ Stream.fromList "1+"
Right ["1"]

>>> Stream.parse p $ Stream.fromList "1+2+3"
Right ["1","2","3"]

Non-backtracking version of sepBy. Several times faster.

Take either the separator or the token. Separator is a Left value and token is Right value. Unimplemented