Invalid code generation for "pluck"
LeviticusMB opened this issue · 5 comments
The list example from Peggy does not work as intended:
list = head:word tail:(_ "," _ @word)* { return [head, ...tail]; }
word = $[a-z]i+
_ = [ \t]*
If invoked via tspegjs, there is no code difference in the TypeScript output if I change @word to just word in the first rule. On the other hand, if I invoke peggy (1.2.0) directly, the generated code (JavaScript) differs as expected:
727c728,729
< s3 = s7;
---
> s4 = [s4, s5, s6, s7];
> s3 = s4;OK. I see. We will need to add support for the "pluck" operator. It is not supported currently.
Thanks for reporting it. @LeviticusMB
Would you take a PR on this? Just ran into it here.
How much do you want to bring your generate-bytecode-ts.js up to synchronization with peggy? What are the key differences? In particular, there are more invasive changes coming that you can use for sourcemaping, if you want.
I propose to start with a small patch that just adds support for opcode 36:
// [36] PLUCK n, k, p1, ..., pK
//
// value = [stack[p1], ..., stack[pK]]; // when k != 1
// -or-
// value = stack[p1]; // when k == 1
//
// stack.pop(n);
// stack.push(value);and the equivalent generate-ts bits.