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import type { TracingLogger } from './utils';
import * as readline from 'node:readline/promises';
import { stdin as input, stdout as output } from 'node:process';
import { peggyParse } from './parser';
import { evaluate } from './interpreter';
// cool asci logo for CPS
const LOGO = `
_______ ________ ______ _______ __
/ \\ / | / \\ / \\ / |
$$$$$$$ |$$$$$$$$/ /$$$$$$ |$$$$$$$ |$$ |
$$ |__$$ |$$ |__ $$ | $$/ $$ |__$$ |$$ |
$$ $$< $$ | $$ | $$ $$/ $$ |
$$$$$$$ |$$$$$/ $$ | __ $$$$$$$/ $$ |
$$ | $$ |$$ |_____ $$ \\__/ |$$ | $$ |_____
$$ | $$ |$$ |$$ $$/ $$ | $$ |
$$/ $$/ $$$$$$$$/ $$$$$$/ $$/ $$$$$$$$/
`;
const HELP = `
This is the CPS REPL. You can enter CPS programs and see the result of evaluating them.
This REPL supports multi-line input. To end a multi-line input, enter an empty line.
Commands:
help - Show this message
exit - Exit the REPL
About:
Read "Compiling With Continuations" by Andrew W. Appel for more information about
this Intermediate Representation.
Example:
~> PRIMOP(+, [INT 1, INT 2], [result], [
| APP(LABEL id, [VAR result])
| ])
`;
export const doRepl = async (
logger: TracingLogger,
prompt = 0,
rl = readline.createInterface({ input, output }),
): Promise<any> => {
if (prompt === 0) {
logger.info('welcome to recpl (read eval continue print loop) :)' + LOGO);
}
const promptString = `[ ${prompt} ] ~> `;
const lines: string[] = [await rl.question(promptString)];
while (lines.at(-1)) {
const line = lines.at(-1)!;
if (lines.length === 1 && line === 'help') {
logger.info(HELP);
return doRepl(logger, prompt + 1, rl);
}
if (line === 'exit') {
logger.info('Exiting REPL...');
rl.close();
return;
}
lines.push(
await rl.question(`|`.padStart(promptString.length - 1, ' ') + ' '),
);
}
const program = lines.slice(0, -1).join('\n');
try {
const ast = peggyParse(program);
logger.debug('AST: ' + JSON.stringify(ast, null, 2));
const result = await evaluate(ast, logger.createChild('evaluate'));
logger.info('Result: ' + JSON.stringify(result, null, 2) + '\n');
} catch (e) {
logger.error(e!.toString() + '\n');
}
return doRepl(logger, prompt + 1, rl);
};
|
