Inside 245-5D

Existential Pontification and Generalized Abstract Digressions

Left-recursive parsing of Haskell imports and declarations

Suppose that you want to parse a list separated by newlines, but you want to automatically ignore extra newlines (just in the same way that import declarations in a Haskell file can be separated by one or more newlines.) Historically, GHC has used a curious grammar to perform this parse (here, semicolons represent newlines): decls […]

  • December 21, 2016