Writing a (dis-)assembler for 8-bit code in D - blog posts

[Brian]

On Tuesday, 20 April 2021 at 10:02:05 UTC, Dukc wrote:
> TlDr: `private` means the symbol can only be used in the same 
> file.

That's clearly what I was looking for, thanks.

> You probably want to learn about `foreach` loop.

Oh, yes. I certainly know what a foreach loop is. D is hardly the 
only language to provide it. I actively chose against using it; 
long boring story short, it's the result of some self-bias I have 
from many years on a particular kind of coding research team I 
used to be on as a grad student. Looking back at the finished 
code, it was a decision that didn't bear out as I was hoping. As 
there are only 12 for loops (and no other types of loops, again, 
on purpose) in the whole assembler, that's probably a design 
decision that I would not have selected if I were going to start 
over. In fact, the new parser abandons the idea already.

So I agree: converting all the for loops to foreach loops would 
be a nice additional blog post. Thanks.

> `static foreach` has a lot of potential to shorten your 
> assembler code.
> ```D
> sw: switch (op)
> {   //iterates over the array at compile time
>     static foreach(opStr; ["nop", "lxi", "stax", "inx", "inr", 
> "dcr", "mvi", <...>])
>     {	case opStr:
>         mixin(opStr)(); //inserts a call to function with name 
> opStr.
>         break sw; //breaks out of the switch statement
>     }
>
>     default: err("unknown opcode: " ~ op);
> }
> ```
>
> Even better is if you make a global array of opCodes and pass 
> that to `static foreach`. The opcode array needs to be 
> available in compile time, so mark it `enum` instead of 
> `immutable`, like: `enum opcodes = ["nop", "lxi", "stax", 
> <...>];`

I should spend some time looking at mixins. The rest you have 
there makes intuitive sense looking at it. (Crazy question: is 
there a way to dump internal state after semantic analysis?)

Looking at the mixins page here: 
https://dlang.org/articles/mixin.html, I am already disappointed 
to learn about the monkey business it won't let me do :) I was 
really hoping to radically alter the syntax of D to create my own 
language and then implement an entirely different language in 
that (I kid, but only slightly. That's exactly what Arthur 
Whitney does in his language development: K being a good example 
of this.)

~Brian