classNullableSet

final class NullableSet

Restricted visibility: declared "@visibility root". Code outside that scope must not name this declaration.

The nonterminals that can derive the empty string.

Methods§

public function __construct(Grammar $grammar)

Computes the set by iterating over the rules until nothing changes.

$grammar Grammar Grammar to inspect

public function isNullable(int $symbol): bool

Reports whether a symbol derives the empty string.

$symbol int Symbol number

bool True for a nullable nonterminal, false for terminals and other nonterminals

Test cases 1

Called from 1

public function tailNullable(list<int> $symbols, int $from): bool

Reports whether every symbol from a position onward derives the empty string.

`$symbols`	`list<int>`	Symbols to inspect
`$from`	`int`	Position to start at

bool True when the tail is empty or all of it is nullable

Test cases 1

Called from 1

Calls 1

Implementation details, listed for orientation only.

private array<int, true> $nullable

Test cases that cover or call this symbol, from the coverage report and from the analyzed test sources.

Dedicated tests 2

Other tests reaching this symbol 5

Instantiated in 1

Method calls 2

Type declarations 2