std/toml/_parser.ts
2024-08-21 16:15:14 +09:00

806 lines
20 KiB
TypeScript

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
import { deepMerge } from "@std/collections/deep-merge";
// ---------------------------
// Interfaces and base classes
// ---------------------------
interface Success<T> {
ok: true;
body: T;
}
interface Failure {
ok: false;
}
type ParseResult<T> = Success<T> | Failure;
type ParserComponent<T = unknown> = (scanner: Scanner) => ParseResult<T>;
type BlockParseResultBody = {
type: "Block";
value: Record<string, unknown>;
} | {
type: "Table";
key: string[];
value: Record<string, unknown>;
} | {
type: "TableArray";
key: string[];
value: Record<string, unknown>;
};
export class Scanner {
#whitespace = /[ \t]/;
#position = 0;
#source: string;
constructor(source: string) {
this.#source = source;
}
/**
* Get current character
* @param index - relative index from current position
*/
char(index = 0) {
return this.#source[this.#position + index] ?? "";
}
/**
* Get sliced string
* @param start - start position relative from current position
* @param end - end position relative from current position
*/
slice(start: number, end: number): string {
return this.#source.slice(this.#position + start, this.#position + end);
}
/**
* Move position to next
*/
next(count?: number) {
if (typeof count === "number") {
for (let i = 0; i < count; i++) {
this.#position++;
}
} else {
this.#position++;
}
}
/**
* Move position until current char is not a whitespace, EOL, or comment.
* @param options.inline - skip only whitespaces
*/
nextUntilChar(
options: { inline?: boolean; comment?: boolean } = { comment: true },
) {
if (options.inline) {
while (this.#whitespace.test(this.char()) && !this.eof()) {
this.next();
}
} else {
while (!this.eof()) {
const char = this.char();
if (this.#whitespace.test(char) || this.isCurrentCharEOL()) {
this.next();
} else if (options.comment && this.char() === "#") {
// entering comment
while (!this.isCurrentCharEOL() && !this.eof()) {
this.next();
}
} else {
break;
}
}
}
// Invalid if current char is other kinds of whitespace
if (!this.isCurrentCharEOL() && /\s/.test(this.char())) {
const escaped = "\\u" + this.char().charCodeAt(0).toString(16);
const position = this.#position;
throw new SyntaxError(
`Cannot parse the TOML: It contains invalid whitespace at position '${position}': \`${escaped}\``,
);
}
}
/**
* Position reached EOF or not
*/
eof() {
return this.position() >= this.#source.length;
}
/**
* Get current position
*/
position() {
return this.#position;
}
isCurrentCharEOL() {
return this.char() === "\n" || this.slice(0, 2) === "\r\n";
}
}
// -----------------------
// Utilities
// -----------------------
function success<T>(body: T): Success<T> {
return { ok: true, body };
}
function failure(): Failure {
return { ok: false };
}
export function unflat(
keys: string[],
values: unknown = {},
cObj?: unknown,
): Record<string, unknown> {
const out: Record<string, unknown> = {};
if (keys.length === 0) {
return cObj as Record<string, unknown>;
}
if (!cObj) cObj = values;
const key: string | undefined = keys[keys.length - 1];
if (typeof key === "string") out[key] = cObj;
return unflat(keys.slice(0, -1), values, out);
}
export function deepAssignWithTable(target: Record<string, unknown>, table: {
type: "Table" | "TableArray";
key: string[];
value: Record<string, unknown>;
}) {
if (table.key.length === 0 || table.key[0] == null) {
throw new Error(
"Cannot parse the TOML: key length is not a positive number",
);
}
const value = target[table.key[0]];
if (typeof value === "undefined") {
Object.assign(
target,
unflat(
table.key,
table.type === "Table" ? table.value : [table.value],
),
);
} else if (Array.isArray(value)) {
if (table.type === "TableArray" && table.key.length === 1) {
value.push(table.value);
} else {
const last = value[value.length - 1];
deepAssignWithTable(last, {
type: table.type,
key: table.key.slice(1),
value: table.value,
});
}
} else if (typeof value === "object" && value !== null) {
deepAssignWithTable(value as Record<string, unknown>, {
type: table.type,
key: table.key.slice(1),
value: table.value,
});
} else {
throw new Error("Unexpected assign");
}
}
// ---------------------------------
// Parser combinators and generators
// ---------------------------------
function or<T>(parsers: ParserComponent<T>[]): ParserComponent<T> {
return (scanner: Scanner): ParseResult<T> => {
for (const parse of parsers) {
const result = parse(scanner);
if (result.ok) return result;
}
return failure();
};
}
function join<T>(
parser: ParserComponent<T>,
separator: string,
): ParserComponent<T[]> {
const Separator = character(separator);
return (scanner: Scanner): ParseResult<T[]> => {
const first = parser(scanner);
if (!first.ok) return failure();
const out: T[] = [first.body];
while (!scanner.eof()) {
if (!Separator(scanner).ok) break;
const result = parser(scanner);
if (!result.ok) {
throw new SyntaxError(`Invalid token after "${separator}"`);
}
out.push(result.body);
}
return success(out);
};
}
function kv<T>(
keyParser: ParserComponent<string[]>,
separator: string,
valueParser: ParserComponent<T>,
): ParserComponent<{ [key: string]: unknown }> {
const Separator = character(separator);
return (scanner: Scanner): ParseResult<{ [key: string]: unknown }> => {
const key = keyParser(scanner);
if (!key.ok) return failure();
const sep = Separator(scanner);
if (!sep.ok) {
throw new SyntaxError(`key/value pair doesn't have "${separator}"`);
}
const value = valueParser(scanner);
if (!value.ok) {
throw new SyntaxError(
`Value of key/value pair is invalid data format`,
);
}
return success(unflat(key.body, value.body));
};
}
function merge(
parser: ParserComponent<unknown[]>,
): ParserComponent<Record<string, unknown>> {
return (scanner: Scanner): ParseResult<Record<string, unknown>> => {
const result = parser(scanner);
if (!result.ok) return failure();
let body = {};
for (const record of result.body) {
if (typeof body === "object" && body !== null) {
// deno-lint-ignore no-explicit-any
body = deepMerge(body, record as Record<any, any>);
}
}
return success(body);
};
}
function repeat<T>(
parser: ParserComponent<T>,
): ParserComponent<T[]> {
return (scanner: Scanner) => {
const body: T[] = [];
while (!scanner.eof()) {
const result = parser(scanner);
if (!result.ok) break;
body.push(result.body);
scanner.nextUntilChar();
}
if (body.length === 0) return failure();
return success(body);
};
}
function surround<T>(
left: string,
parser: ParserComponent<T>,
right: string,
): ParserComponent<T> {
const Left = character(left);
const Right = character(right);
return (scanner: Scanner) => {
if (!Left(scanner).ok) {
return failure();
}
const result = parser(scanner);
if (!result.ok) {
throw new SyntaxError(`Invalid token after "${left}"`);
}
if (!Right(scanner).ok) {
throw new SyntaxError(
`Not closed by "${right}" after started with "${left}"`,
);
}
return success(result.body);
};
}
function character(str: string) {
return (scanner: Scanner): ParseResult<void> => {
scanner.nextUntilChar({ inline: true });
if (scanner.slice(0, str.length) !== str) return failure();
scanner.next(str.length);
scanner.nextUntilChar({ inline: true });
return success(undefined);
};
}
// -----------------------
// Parser components
// -----------------------
const BARE_KEY_REGEXP = /[A-Za-z0-9_-]/;
const FLOAT_REGEXP = /[0-9_\.e+\-]/i;
const END_OF_VALUE_REGEXP = /[ \t\r\n#,}\]]/;
export function bareKey(scanner: Scanner): ParseResult<string> {
scanner.nextUntilChar({ inline: true });
if (!scanner.char() || !BARE_KEY_REGEXP.test(scanner.char())) {
return failure();
}
const acc: string[] = [];
while (scanner.char() && BARE_KEY_REGEXP.test(scanner.char())) {
acc.push(scanner.char());
scanner.next();
}
const key = acc.join("");
return success(key);
}
function escapeSequence(scanner: Scanner): ParseResult<string> {
if (scanner.char() !== "\\") return failure();
scanner.next();
// See https://toml.io/en/v1.0.0-rc.3#string
switch (scanner.char()) {
case "b":
scanner.next();
return success("\b");
case "t":
scanner.next();
return success("\t");
case "n":
scanner.next();
return success("\n");
case "f":
scanner.next();
return success("\f");
case "r":
scanner.next();
return success("\r");
case "u":
case "U": {
// Unicode character
const codePointLen = scanner.char() === "u" ? 4 : 6;
const codePoint = parseInt(
"0x" + scanner.slice(1, 1 + codePointLen),
16,
);
const str = String.fromCodePoint(codePoint);
scanner.next(codePointLen + 1);
return success(str);
}
case '"':
scanner.next();
return success('"');
case "\\":
scanner.next();
return success("\\");
default:
throw new SyntaxError(
`Invalid escape sequence: \\${scanner.char()}`,
);
}
}
export function basicString(scanner: Scanner): ParseResult<string> {
scanner.nextUntilChar({ inline: true });
if (scanner.char() !== '"') return failure();
scanner.next();
const acc = [];
while (scanner.char() !== '"' && !scanner.eof()) {
if (scanner.char() === "\n") {
throw new SyntaxError("Single-line string cannot contain EOL");
}
const escapedChar = escapeSequence(scanner);
if (escapedChar.ok) {
acc.push(escapedChar.body);
} else {
acc.push(scanner.char());
scanner.next();
}
}
if (scanner.eof()) {
throw new SyntaxError(
`Single-line string is not closed:\n${acc.join("")}`,
);
}
scanner.next(); // skip last '""
return success(acc.join(""));
}
export function literalString(scanner: Scanner): ParseResult<string> {
scanner.nextUntilChar({ inline: true });
if (scanner.char() !== "'") return failure();
scanner.next();
const acc: string[] = [];
while (scanner.char() !== "'" && !scanner.eof()) {
if (scanner.char() === "\n") {
throw new SyntaxError("Single-line string cannot contain EOL");
}
acc.push(scanner.char());
scanner.next();
}
if (scanner.eof()) {
throw new SyntaxError(
`Single-line string is not closed:\n${acc.join("")}`,
);
}
scanner.next(); // skip last "'"
return success(acc.join(""));
}
export function multilineBasicString(
scanner: Scanner,
): ParseResult<string> {
scanner.nextUntilChar({ inline: true });
if (scanner.slice(0, 3) !== '"""') return failure();
scanner.next(3);
if (scanner.char() === "\n") {
// The first newline (LF) is trimmed
scanner.next();
} else if (scanner.slice(0, 2) === "\r\n") {
// The first newline (CRLF) is trimmed
scanner.next(2);
}
const acc: string[] = [];
while (scanner.slice(0, 3) !== '"""' && !scanner.eof()) {
// line ending backslash
if (scanner.slice(0, 2) === "\\\n") {
scanner.next();
scanner.nextUntilChar({ comment: false });
continue;
} else if (scanner.slice(0, 3) === "\\\r\n") {
scanner.next();
scanner.nextUntilChar({ comment: false });
continue;
}
const escapedChar = escapeSequence(scanner);
if (escapedChar.ok) {
acc.push(escapedChar.body);
} else {
acc.push(scanner.char());
scanner.next();
}
}
if (scanner.eof()) {
throw new SyntaxError(
`Multi-line string is not closed:\n${acc.join("")}`,
);
}
// if ends with 4 `"`, push the fist `"` to string
if (scanner.char(3) === '"') {
acc.push('"');
scanner.next();
}
scanner.next(3); // skip last '""""
return success(acc.join(""));
}
export function multilineLiteralString(
scanner: Scanner,
): ParseResult<string> {
scanner.nextUntilChar({ inline: true });
if (scanner.slice(0, 3) !== "'''") return failure();
scanner.next(3);
if (scanner.char() === "\n") {
// The first newline (LF) is trimmed
scanner.next();
} else if (scanner.slice(0, 2) === "\r\n") {
// The first newline (CRLF) is trimmed
scanner.next(2);
}
const acc: string[] = [];
while (scanner.slice(0, 3) !== "'''" && !scanner.eof()) {
acc.push(scanner.char());
scanner.next();
}
if (scanner.eof()) {
throw new SyntaxError(
`Multi-line string is not closed:\n${acc.join("")}`,
);
}
// if ends with 4 `'`, push the fist `'` to string
if (scanner.char(3) === "'") {
acc.push("'");
scanner.next();
}
scanner.next(3); // skip last "'''"
return success(acc.join(""));
}
const symbolPairs: [string, unknown][] = [
["true", true],
["false", false],
["inf", Infinity],
["+inf", Infinity],
["-inf", -Infinity],
["nan", NaN],
["+nan", NaN],
["-nan", NaN],
];
export function symbols(scanner: Scanner): ParseResult<unknown> {
scanner.nextUntilChar({ inline: true });
const found = symbolPairs.find(([str]) =>
scanner.slice(0, str.length) === str
);
if (!found) return failure();
const [str, value] = found;
scanner.next(str.length);
return success(value);
}
export const dottedKey = join(or([bareKey, basicString, literalString]), ".");
export function integer(scanner: Scanner): ParseResult<number | string> {
scanner.nextUntilChar({ inline: true });
// If binary / octal / hex
const first2 = scanner.slice(0, 2);
if (first2.length === 2 && /0(?:x|o|b)/i.test(first2)) {
scanner.next(2);
const acc = [first2];
while (/[0-9a-f_]/i.test(scanner.char()) && !scanner.eof()) {
acc.push(scanner.char());
scanner.next();
}
if (acc.length === 1) return failure();
return success(acc.join(""));
}
const acc = [];
if (/[+-]/.test(scanner.char())) {
acc.push(scanner.char());
scanner.next();
}
while (/[0-9_]/.test(scanner.char()) && !scanner.eof()) {
acc.push(scanner.char());
scanner.next();
}
if (acc.length === 0 || (acc.length === 1 && /[+-]/.test(acc[0]!))) {
return failure();
}
const int = parseInt(acc.filter((char) => char !== "_").join(""));
return success(int);
}
export function float(scanner: Scanner): ParseResult<number> {
scanner.nextUntilChar({ inline: true });
// lookahead validation is needed for integer value is similar to float
let position = 0;
while (
scanner.char(position) &&
!END_OF_VALUE_REGEXP.test(scanner.char(position))
) {
if (!FLOAT_REGEXP.test(scanner.char(position))) return failure();
position++;
}
const acc = [];
if (/[+-]/.test(scanner.char())) {
acc.push(scanner.char());
scanner.next();
}
while (FLOAT_REGEXP.test(scanner.char()) && !scanner.eof()) {
acc.push(scanner.char());
scanner.next();
}
if (acc.length === 0) return failure();
const float = parseFloat(acc.filter((char) => char !== "_").join(""));
if (isNaN(float)) return failure();
return success(float);
}
export function dateTime(scanner: Scanner): ParseResult<Date> {
scanner.nextUntilChar({ inline: true });
let dateStr = scanner.slice(0, 10);
// example: 1979-05-27
if (!/^\d{4}-\d{2}-\d{2}/.test(dateStr)) return failure();
scanner.next(10);
const acc = [];
// example: 1979-05-27T00:32:00Z
while (/[ 0-9TZ.:-]/.test(scanner.char()) && !scanner.eof()) {
acc.push(scanner.char());
scanner.next();
}
dateStr += acc.join("");
const date = new Date(dateStr.trim());
// invalid date
if (isNaN(date.getTime())) {
throw new SyntaxError(`Invalid date string "${dateStr}"`);
}
return success(date);
}
export function localTime(scanner: Scanner): ParseResult<string> {
scanner.nextUntilChar({ inline: true });
let timeStr = scanner.slice(0, 8);
if (!/^(\d{2}):(\d{2}):(\d{2})/.test(timeStr)) return failure();
scanner.next(8);
const acc = [];
if (scanner.char() !== ".") return success(timeStr);
acc.push(scanner.char());
scanner.next();
while (/[0-9]/.test(scanner.char()) && !scanner.eof()) {
acc.push(scanner.char());
scanner.next();
}
timeStr += acc.join("");
return success(timeStr);
}
export function arrayValue(scanner: Scanner): ParseResult<unknown[]> {
scanner.nextUntilChar({ inline: true });
if (scanner.char() !== "[") return failure();
scanner.next();
const array: unknown[] = [];
while (!scanner.eof()) {
scanner.nextUntilChar();
const result = value(scanner);
if (!result.ok) break;
array.push(result.body);
scanner.nextUntilChar({ inline: true });
// may have a next item, but trailing comma is allowed at array
if (scanner.char() !== ",") break;
scanner.next();
}
scanner.nextUntilChar();
if (scanner.char() !== "]") throw new SyntaxError("Array is not closed");
scanner.next();
return success(array);
}
export function inlineTable(
scanner: Scanner,
): ParseResult<Record<string, unknown>> {
scanner.nextUntilChar();
if (scanner.char(1) === "}") {
scanner.next(2);
return success({});
}
const pairs = surround(
"{",
join(pair, ","),
"}",
)(scanner);
if (!pairs.ok) return failure();
let table = {};
for (const pair of pairs.body) {
table = deepMerge(table, pair);
}
return success(table);
}
export const value = or([
multilineBasicString,
multilineLiteralString,
basicString,
literalString,
symbols,
dateTime,
localTime,
float,
integer,
arrayValue,
inlineTable,
]);
export const pair = kv(dottedKey, "=", value);
export function block(
scanner: Scanner,
): ParseResult<BlockParseResultBody> {
scanner.nextUntilChar();
const result = merge(repeat(pair))(scanner);
if (result.ok) return success({ type: "Block", value: result.body });
return failure();
}
export const tableHeader = surround("[", dottedKey, "]");
export function table(scanner: Scanner): ParseResult<BlockParseResultBody> {
scanner.nextUntilChar();
const header = tableHeader(scanner);
if (!header.ok) return failure();
scanner.nextUntilChar();
const b = block(scanner);
return success({
type: "Table",
key: header.body,
value: b.ok ? b.body.value : {},
});
}
export const tableArrayHeader = surround("[[", dottedKey, "]]");
export function tableArray(
scanner: Scanner,
): ParseResult<BlockParseResultBody> {
scanner.nextUntilChar();
const header = tableArrayHeader(scanner);
if (!header.ok) return failure();
scanner.nextUntilChar();
const b = block(scanner);
return success({
type: "TableArray",
key: header.body,
value: b.ok ? b.body.value : {},
});
}
export function toml(
scanner: Scanner,
): ParseResult<Record<string, unknown>> {
const blocks = repeat(or([block, tableArray, table]))(scanner);
if (!blocks.ok) return failure();
let body = {};
for (const block of blocks.body) {
switch (block.type) {
case "Block": {
body = deepMerge(body, block.value);
break;
}
case "Table": {
deepAssignWithTable(body, block);
break;
}
case "TableArray": {
deepAssignWithTable(body, block);
break;
}
}
}
return success(body);
}
export function parserFactory<T>(parser: ParserComponent<T>) {
return (tomlString: string): T => {
const scanner = new Scanner(tomlString);
let parsed: ParseResult<T> | null = null;
let err: Error | null = null;
try {
parsed = parser(scanner);
} catch (e) {
err = e instanceof Error ? e : new Error("Invalid error type caught");
}
if (err || !parsed || !parsed.ok || !scanner.eof()) {
const position = scanner.position();
const subStr = tomlString.slice(0, position);
const lines = subStr.split("\n");
const row = lines.length;
const column = (() => {
let count = subStr.length;
for (const line of lines) {
if (count <= line.length) break;
count -= line.length + 1;
}
return count;
})();
const message = `Parse error on line ${row}, column ${column}: ${
err ? err.message : `Unexpected character: "${scanner.char()}"`
}`;
throw new SyntaxError(message);
}
return parsed.body;
};
}