str/src/vm/commands/quote.ts

import {Command, ParseContext, StrTerm} from "./command.js";
import {LexInput} from "../lexer.js";
import {StrVM} from "../vm.js";
import {Awaitable} from "../../util/types.js";

export const QUOTEMARKS = ['"', '\'', '`']

export const stripQuotemarkLayer = (s: string, marks?: string[]): string => {
    if ( !marks ) {
        marks = QUOTEMARKS
    }

    for ( const mark of marks ) {
        if ( !s.startsWith(mark) || !s.endsWith(mark) ) {
            continue
        }

        s = s.substring(mark.length, s.length - mark.length)
        break
    }

    return s
}

export class Quote extends Command<{ with?: StrTerm }> {
    attemptParse(context: ParseContext): { with?: StrTerm } {
        return {
            with: context.popOptionalTerm(),
        }
    }

    getDisplayName(): string {
        return 'quote'
    }

    isParseCandidate(token: LexInput): boolean {
        return this.isKeyword(token, 'quote')
    }

    execute(vm: StrVM, data: { with?: StrTerm }): Awaitable<StrVM> {
        return vm.replaceContextMatchingTerm(ctx => ({
            string: sub => {
                let quote = '\''
                if ( data.with ) {
                    quote = ctx.resolveString(data.with)
                }

                sub = stripQuotemarkLayer(sub)
                sub = sub.replaceAll(quote, `\\${quote}`)
                return `${quote}${sub}${quote}`
            }
        }))
    }
}