tree 4b6f2dedc4115a3dcec65778d5faad42236fa459
parent 3dc5f4e948b1114c37a9afd3060dacf099892689
author William Langford <wlangfor@gmail.com> 1534560433 -0400
committer William Langford <wlangfor@gmail.com> 1534562148 -0400

Fix destructuring alternation

Attempting to use the existing FORK_OPT opcode resulted in difficulty
knowing when to pop an error message off the stack and when not to. This
commit makes DESTRUCTURE_ALT a real opcode that is identical to
FORK_OPT, except for never pushing the error message onto the stack when
continuing from an error backtrack.

Some small changes were necessary to the DUP/POP behavior surrounding
destructuring to accomodate this.