Function parseFnExpr

src/parser/syntaxes/expressions.ts:415–439

* ```abnf * FnExpr = "@" [TypeParams] Params [":" Type] Block * ```

(s: ITokenStream)

 * ```
*/
function parseFnExpr(s: ITokenStream): Ast.Fn {
	const startPos = s.getPos();

	s.expect(TokenKind.At);
	s.next();

	let typeParams: Ast.TypeParam[];
	if (s.is(TokenKind.Lt)) {
		typeParams = parseTypeParams(s);
	} else {
		typeParams = [];
	}

	const params = parseParams(s);

	let type: Ast.TypeSource | undefined;
	if (s.is(TokenKind.Colon)) {
		s.next();
		type = parseType(s);
	}

	const body = parseBlock(s);

	return NODE('fn', { typeParams, params, retType: type, children: body }, startPos, s.getPos());
}

/**
 * ```abnf