src/syntax/parsers/lazy_parser.ghul

1		namespace Syntax.Parsers is
2		use IO.Std
3
4		class LAZY_PARSER[T: class]: Parser[T] is
5		_parser: System.Lazy[Parser[T]]?
6
7		create: () -> Parser[T] public
8		= value is
9		_parser = System.Lazy[Parser[T]](value)
10		si
11
12		init() is
13		super.init()
14		si
15
16		// The parser this stands in for, created on first use.
17		value() -> Parser[T] is
18		let parser = _parser
19
20		assert parser? else "Lazy parser is null: {self}"
21
22		let v = parser.value
23
24		assert v? else "Lazy parser value is null: {_parser}"
25
26		return v
27		si
28
29		parse(context: CONTEXT) -> T? is
30		let parser = _parser
31
32		assert parser? else "Lazy parser is null: {self}"
33
34		let v = parser.value
35
36		assert v? else "Lazy parser value is null: {_parser}"
37
38		return v.parse(context)
39		si
40		si
41
42		si