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== Goal
A memory-safe language with a simple translator to x86 that can be feasibly written in x86.
== Definitions of terms
Memory-safe: it should be impossible to:
a) create a pointer out of arbitrary data, or
b) to access heap memory after it's been freed.
Simple: do all the work in a 2-pass translator:
Pass 1: check each instruction's types in isolation.
Pass 2: emit code for each instruction in isolation.
== types
int
char
(address _ t), t ∋ {stack, heap, global}
(array _ t), t ∋ {stack, heap, global}
stack addresses can't be copied to heap or global
heap addresses can't be copied [1]
global addresses you're free to use anywhere
[1] (address _ heap) can't be copied or stored, can't be part of a type or
choice. Only thing you can do with it is access it from the register you wrote
it to. And even that not past a call instruction. Important detail: `free()`
is a call. So an address to something on the heap can never be invalid if the
program type-checks.
<reg x> : (address T m) <- advance <reg/mem> : (array T m), <reg offset> : (index T)
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