Fun programming exercise

Off and on I work on my implementation of JavaScript in PLT Scheme. Implementing the standard library means translating the spec's low-level, imperative pseudocode (think GW-BASIC) to Scheme. It's a fun and mostly mindless exercise to take code with assignments and goto, translate that into mutually tail-calling basic blocks, eliminate the assignments by parameterization, and then finally polish it into a more idiomatic style. Sort of my version of a Sudoku puzzle or something.