Using Parsec to parse regular expressions - Stack Overflow 13 You should use Parsec Expr buildExprParser; it is ideal for this purpose You simply describe your operators, their precedence and associativity, and how to parse an atom, and the combinator builds the parser for you! You probably also want to add the ability to group terms with parens so that you can apply * to more than just a single literal
Simply using parsec in python - Stack Overflow The design of parsec requires a Parser to act independently on an input stream without knowledge of any other Parser To do this effectively a Parser must manage an index position of the input string
ghc error: hidden package, but its actually exposed parsec-3 1 14 0 is not the same package as parsec-3 1 13 0 Something else is going on How did you install the package? What environment are you running ghc in? What's the full output of ghc-pkg list?
parsing - Parsec `try` should backtrack - Stack Overflow Isn't Parsec's try supposed to backtrack when it encounters failure? For instance, if I have the code import Control Applicative (( lt;| gt;)) import Debug Trace import Text Parsec (try) import Text
Parsec vs Yacc Bison Antlr: Why and when to use Parsec? My understanding is that Parsec creates a nice DSL of writing parsers and Haskell makes it very easy and expressive But parsing is such a standard popular technology that deserves its own language, which outputs to multiple target languages So when shall we use Parsec instead of, say, generating Haskell code from Bison Antlr?
Parsec: difference between try and lookAhead? The combinators try and lookAhead are similar in that they both let Parsec "rewind", but they apply in different circumstances In particular, try rewinds failure while lookAhead rewinds success
Writing a parser from scratch in Haskell - Stack Overflow It's actually surprisingly easy to build Parsec-from-scratch The actual library code itself is heavily generalized and optimized which contorts the core abstraction, but if you're just building things from scratch to understand more about what's going on you can write it in just a few lines of code I'll build a slightly weaker Applicative parser below Essentially, we want to produce a
Whats the cleanest way to do case-insensitive parsing with Text . . . No, Parsec cannot do that in clean way string is implemented on top of primitive tokens combinator that is hard-coded to use equality test (==) It's a bit simpler to parse case-insensitive character, but you probably want more