@eagleoutice/flowr-dev/cli/repl/ghost-hint.js

Static Dataflow Analyzer and Program Slicer for the R Programming Language

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ghostHintClearSequence = exports.defaultReplHint = void 0;
exports.ghostHintShowSequence = ghostHintShowSequence;
exports.ghostHintEnabled = ghostHintEnabled;
exports.installGhostHint = installGhostHint;
exports.defaultReplHint = ':help · Tab completes · :query @config +repl.hints=false to hide';
/** ANSI that draws the dimmed `hint` and restores the cursor to where it was. */
function ghostHintShowSequence(hint) {
    return `\x1b7\x1b[2m${hint}\x1b[0m\x1b8`;
}
exports.ghostHintClearSequence = '\x1b[0K';
const noopController = { show: () => { }, clear: () => { } };
/** Whether hints may be shown: enabled in the config and on an interactive TTY (honoring `NO_COLOR`/`TERM=dumb`). */
function ghostHintEnabled(config, env = process.env, stdout = process.stdout, stdin = process.stdin) {
    return Boolean(config.repl.hints && stdout.isTTY && stdin.isTTY && !env.NO_COLOR && env.TERM !== 'dumb');
}
/**
 * Installs an opt-out ghost hint on the REPL prompt: a dim placeholder on the empty prompt and, as the user
 * types, a dim preview of the best Tab-completion. A no-op on non-interactive terminals (see
 * {@link ghostHintEnabled}) and whenever the text would not fit the line, so it can never wrap or corrupt output.
 */
function installGhostHint(rl, config, { hint = exports.defaultReplHint, suggest } = {}, io = { stdin: process.stdin, stdout: process.stdout }) {
    if (!ghostHintEnabled(config, process.env, io.stdout, io.stdin)) {
        return noopController;
    }
    const state = rl;
    const getLine = () => state.line ?? '';
    const cursorAtEnd = () => state.cursor === undefined || state.cursor === getLine().length;
    const fits = (text) => getLine().length + text.length + 6 < (io.stdout.columns ?? 80);
    let shown = false;
    const clear = () => {
        if (shown) {
            io.stdout.write(exports.ghostHintClearSequence);
            shown = false;
        }
    };
    const render = (text) => {
        clear();
        if (text && fits(text)) {
            io.stdout.write(ghostHintShowSequence(text));
            shown = true;
        }
    };
    const update = () => {
        if (!config.repl.hints) {
            clear();
            return;
        }
        const line = getLine();
        if (line.length === 0) {
            render(hint);
        }
        else if (cursorAtEnd()) {
            render(suggest?.(line) ?? '');
        }
        else {
            clear();
        }
    };
    io.stdin.prependListener('keypress', clear);
    io.stdin.on('keypress', (_s, key) => {
        if (!isSubmitKey(key)) {
            update();
        }
    });
    return { show: update, clear };
}
function isSubmitKey(key) {
    return key?.name === 'return' || key?.name === 'enter';
}
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