Ornery Types and Their Associated Grammars

• December 2nd, 2010
• Posted in Uncategorized

My goals are simple: Represent an AST in Haskell and have the type system accurately describe what is permitted in the language. Almost immediately I was foiled. Consider this deceptively simple language: L ::= A | B | C | D A ::= 'a' B ::= 'b' C ::= 'c' '[' {B} ']' D ::= [ READ MORE ]