export const toString = (list: List) => {
if (!isList(list)) {
if (pairs.isPair(list)) {
return `pair: ${pairs.toString(list)}`;
} else if (typeof list === 'object') {
return JSON.stringify(list, null, 2);
}
return list;
}
if (isEmpty(list)) {
return '()';
}
const rec = (p) => {
const first = head(p);
const rest = tail(p);
if (isEmpty(rest)) {
return toString(first);
}
return `${toString(first)}, ${rec(rest)}`;
};
return `(${rec(list)})`;
};
export const isList = (mix: any) => {
if (mix === null) {
return true;
}
if (pairs.isPair(mix)) {
return isList(pairs.cdr(mix));
}
return false;
};
export const checkList = (list: ?List) => {
if (!isList(list)) {
let value;
if (pairs.isPair(list)) {
value = `pair: ${pairs.toString(list)}`;
} else if (typeof list === 'object') {
value = JSON.stringify(list, null, 2);
} else {
value = String(list);
}
throw new Error(`Argument must be list, but it was '${value}'`);
}
};
export const hasChildren = element => isPair(cdr(element));