Function extract_directive

examples/js/repl.js:1079–1088

(a)

    }

    function extract_directive(a) {
        var pos;
        if (a[0] !== '\\')
            return "";
        for (pos = 1; pos < a.length; pos++) {
            if (!is_alpha(a[pos]))
                break;
        }
        return a.substring(1, pos);
    }

    /* return true if the string after cmd can be evaluated as JS */
    function handle_directive(cmd, expr) {