WIP feat: new asm parser

[novusnota]

This is another attempt at making the asm parser — now we're deliberately limiting ourselves to TVM instructions. In the current iteration it's still possible to write code in a very limited subset of Fift, but only if we won't restrict the list of supported TVM instructions in grammar.ts, i.e. during semantical actions on the lexed tokens.

TODO:

• check that I'm going in the right direction before proceeding further (@anton-trunov)
• grammar.ohm
• ast.ts
• grammar.ts
• prettyPrinter.ts → writeFunction.ts (to actually have asm instructions written)
• hash.ts
• compare.ts

Issue

Closes #837.
Closes #1030 (once the grammar.ts is written, there will be a small check for such gotchas).

Checklist

• I have updated CHANGELOG.md
• I have added tests to demonstrate the contribution is correctly implemented: this usually includes both positive and negative tests, showing the happy path(s) and featuring intentionally broken cases
• I have run all the tests locally and no test failure was reported
• I have run the linter, formatter and spellchecker
• I did not do unrelated and/or undiscussed refactorings

[anton-trunov]

Let's start with concrete examples of asm-functions we would like to write and then try to develop some grammar for it. As of now, we should start with instruction sequences and comments (let's use the Tact/Fift syntax for comments).

[novusnota]

we should start with instruction sequences and comments

i.e. no WHILE:<{ … }>DO<{ … }> loops and no similar constructs for now, right?

[anton-trunov]

i.e. no WHILE:<{ … }>DO<{ … }> loops and no similar constructs for now, right?

definitely not using this syntax :)

[anton-trunov]

we might allow asm-blocks to avoid introducing high-level constructions into the assembly language, so the user might able to insert those into loops, etc.

[novusnota]

Hmm, then, something like this we've showed earlier (and have in our tests) won't work anymore:

asm fun isIntAnInt(x: Int): Bool {
    <{
        TRY:<{
            0 PUSHINT ADD DROP -1 PUSHINT
        }>CATCH<{
            2DROP 0 PUSHINT
        }>
    }>CONT 1 1 CALLXARGS
}

Proceed with removing that? This kinda goes against POLA.

UPD: Edited the original post, saying that the full range of Fift+TVM syntax there was highly experimental and subject to change in next releases. Ok, now we can proceed.

[anton-trunov]

we haven't documented it, so there is no backwards compatibility violation

[anton-trunov]

and Tact Kitchen posts are about raw immature things, sneak peek