joeldentici/monadic-js

Algebraic structure implementations, do-notation, and operators to truly live the fantasy

monadic-js's Issues

Left recursion results -- better approach

Right now left recursion curtailment is using parity of the parser to determine whether we should curtail at 1 + remaining length or remaining length. This is necessary for the result to be properly passed back up the recursive call stack when we finally find a parser that doesn't lead to curtailment.

An improvement on what is currently being done is to ignore parity all together and just accept the longest result (by comparing it to the stored result and storing whichever is longer). We can determine the longest result simply by whichever has the furthest position, which removes having to do any error-prone checks on the actual result (which literally should never be done on polymorphic code). This will work regardless of the parity of the parser.

Doing this will make it actually feasible to memoize a lot more of the parsers in the do-notation parse module (since right now it would require calculating the parity of all the parsers). This could lead to much faster parsing of do-notation. In fact, doing this will make it possible to just bring back default memoization if that is desired.