Having finished the first half of https://craftinginterpreters.com in Java (see https://github.com/WanderingStar/jlox), I've embarked in a perhaps silly project to do the second half not in C, but in Swift.
Why? To get myself back in the habit of writing Swift.
But I didn't really feel like using Unsafe pointers, so I'm going to cheat and use Swift arrays (which are dynamic) and pretend that they're not dynamic. Update: Joke's on me. I had to use unsafe pointers for strings.
Also complicating things: I arbitrarily decided to not make the parser, vm, compiler etc. global variables. So I have to store the vm in the compiler and pass it around a bit, and all of the memory allocation code is in the vm, but extensions let me put it in its own file.
Challenges:
- 14.1 RLE line numbers
- 15.3 but lazy. Replaced stack with a Swift stack
- 21.1 lookup constants in the value array
- 22 added PopN
- 22.2 support for
{ var a = 1; { var a = a + 1; print a; } print a; }- which is just commenting out the error line...
- 22.3 added
condeclaration for constants- error if not initialized
- error if assigned after initialization
- global
cons can be redefined, analogously to globalvars
- 25.5 switch
- added Jump if Unequal that only pops one