Menu
So, it seems like Happy is a robust replacement for yacc in Haskell. Is there an equally robust lexer generator to replace lex/flex?
278
Happy is a parser generator system for Haskell, similar to the tool `yacc' for C. Like `yacc', it takes a file containing an annotated BNF specification of a grammar and produces a Haskell module containing a parser for the grammar.
Lex is a lexical analysis tool that can be used to identify specific text strings in a structured way from source text. Yacc is a grammar parser; it reads text and can be used to turn a sequence of words into a structured format for processing.
Lex and Yacc were created in the 1970s as parts of the Unix programming tool set. Both have a number of incarnations for various environments, and are still among the most widely used in their domain. Flex and Bison are improved, modern versions of Lex and Yacc, standardly distributed with most GNU/Linux variants.
The input to Yacc is a grammar with snippets of C code (called "actions") attached to its rules. Its output is a shift-reduce parser in C that executes the C snippets associated with each rule as soon as the rule is recognized.
Alex? http://www.haskell.org/alex/
a tool for generating lexical analysers in Haskell, given a description of the tokens to be recognised in the form of regular expressions. It is similar to the tool lex or flex for C/C++...
Alex is part of the Haskell Platform, so if you install the platform you will automatically have a working Alex.
Alex is also on Hackage. If you have the cabal-install tool (which also comes with the Haskell Platform), then you can build and install the latest version of Alex with
cabal install alexTo find out what the latest version of Alex is, and to download the source separately, go to Alex's HackageDB page.
Alex might also be pre-packaged for your OS...
170
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
