Add a comptime interpreter

[mattco98]

This can process most expressions and statements. The primary goal is to be able to resolve comptime calls in import statements so that the IDE can continue to provide the user with a good experience, however this also comes with the benefit of allowing the user to evaluate arbitrary comptime expression straight from their IDE:

Demo of in-IDE comptime evaluation

Code:

comptime get_names() throws -> [String] {
    mut builder = StringBuilder::create()
    builder.append(b'f')
    builder.append_string("ile2")
    println("Hello.......")
    println("....world!")
    eprintln("oops, some error occurred")
    return ["file1", builder.to_string()]
}

function main() {
    let a = get_names()
}

TODO:

• Struct support
• Match expressions
• Tracking integer/float types (instead of just always using i64/f64)
• Styling the element in the popup that appears when the user evaluates a comptime element. This will require some architectural work in the renderer
• IDE debugging support? It is absolutely possible, just a matter of figuring it out