I’ve come up with a Haskell solution that is 30× faster than the Haskell solution you posted (with my concocted test expression). Major changes: Change Parsec/String to Attoparsec/ByteString In the fact function, change read & many1 digit to decimal Made the chainl1 recursion strict (remove $! for the lazier version). I tried to keep everything … Read more
Since Parsec 3.1.2 support of Data.Text is built-in! See http://hackage.haskell.org/package/parsec-3.1.2 If you are stuck with older version, the code snippets in other answers are helpful, too.
One of the main differences between the tools you listed, is that ANTLR, Bison and their friends are parser generators, whereas Parsec is a parser combinator library. A parser generator reads in a description of a grammar and spits out a parser. It is generally not possible to combine existing grammars into a new grammar, … Read more
At the moment there are two widely used major versions of Parsec: Parsec 2 and Parsec 3. My advice is simply to use the latest release of Parsec 3. But if you want to make a conscientious choice, read on. New in Parsec 3 Monad Transformer Parsec 3 introduces a monad transformer, ParsecT, which can … Read more
The most important difference is that lexing will translate your input domain. A nice result of this is that You do not have to think about whitespace anymore. In a direct (non-lexing) parser, you have to sprinkle space parsers in all places where whitespace is allowed to be, which is easy to forget and it … Read more
The main difference between monadic and applicative parsing is in how sequential composition is handled. In the case of an applicative parser, we use (<*>), whereas with a monad we use (>>=). (<*>) :: Parser (a -> b) -> Parser a -> Parser b (>>=) :: Parser a -> (a -> Parser b) -> Parser … Read more
Parsec Parsec is good for “user-facing” parsers: things where you have a bounded amount of input but error messages matter. It’s not terribly fast, but if you have small inputs this shouldn’t matter. For example, I would choose Parsec for virtually any programming language tools since–in absolute terms–even the largest source files are not that … Read more