feat: goroutines

[shenyih0ng]

Description

This PR implements support for goroutines (GoStatement) with a naive time-quanta based scheduler. Every goroutine is given a randomised quanta of time to run, and once it runs out it is scheduled out for other goroutines. Additionally, the scheduler also looks for the main goroutine, once the main goroutine terminates, the entire program is terminated.

Implementation Details

1. Goroutines exist in the same address space, hence a new goroutine does not reinitialise its own Heap, AstMap or Builtins. However, it does set up its own Control, Stash and Environment
   

   go-slang/src/go-slang/goroutine.ts

   Lines 283 to 290 in f3a4b5a

   	const _C: Control = new Stack()
   	_C.push(H.alloc(body))
   	const _S: Stash = new Stack()
   	const _E = E.copy()
   	.setId(envId)
   	.extend(Object.fromEntries(zip(paramNames, values)))
   	return sched.schedule(new GoRoutine({ C: _C, S: _S, E: _E, B, H, A }, sched))

2. I've also added parser support for strings (StringLit) just so i can print string to stdout to differentiate between goroutines. Note that there is still no string pools and strings do not yet get allocated on the heap! This is purely a convenience feature for debugging

Screen.Recording.2024-04-02.at.11.52.54.AM.mov

[shenyih0ng]

Majority of the diffs come from the changes to generated parser after adding StringLit support, the actual goroutine implementation is ~300-400 lines of changes