Class PHPStan\TrinaryLogic

`final`

Three-valued logic used throughout PHPStan's type system.

Unlike boolean logic, TrinaryLogic has three states: Yes, No, and Maybe. This is essential for static analysis because type relationships aren't always certain. For example, a mixed type might be a string — that's Maybe.

Many Type methods return TrinaryLogic instead of bool because the answer may depend on runtime values that can't be known statically. Extension developers encounter TrinaryLogic extensively when querying type properties:

if ($type->isString()->yes()) {
    // Definitely a string
}
if ($type->isString()->maybe()) {
    // Could be a string (e.g. mixed)
}
if ($type->isString()->no()) {
    // Definitely not a string
}

TrinaryLogic supports logical operations (and, or, negate) that propagate uncertainty correctly. It is used as a flyweight — instances are cached and compared by identity.

Located at src/TrinaryLogic.php

Methods
`public static`	`createYes(): self`	#
`public static`	`createNo(): self`	#
`public static`	`createMaybe(): self`	#
`public static`	`createFromBoolean(bool $value): self`	#
`public`	`yes(): bool`	#
`public`	`maybe(): bool`	#
`public`	`no(): bool`	#
`public`	`toBooleanType(): BooleanType`	#
`public`	`and(?self $operand = null, self ...$rest): self`	#
`public`	`lazyAnd<T>(T[] $objects, callable(T): self $callback): self`	#
`public`	`or(?self $operand = null, self ...$rest): self`	#
`public`	`lazyOr<T>(T[] $objects, callable(T): self $callback): self`	#
`public static`	`extremeIdentity(self ...$operands): self` Returns the operands' value if they all agree, Maybe if any differ. Returns the operands' value if they all agree, Maybe if any differ.	#
`public static`	`lazyExtremeIdentity<T>(T[] $objects, callable(T): self $callback): self`	#
`public static`	`maxMin(self ...$operands): self` Returns Yes if any operand is Yes, otherwise the minimum. Returns Yes if any operand is Yes, otherwise the minimum.	#
`public static`	`lazyMaxMin<T>(T[] $objects, callable(T): self $callback): self`	#
`public`	`negate(): self`	#
`public`	`equals(self $other): bool`	#
`public`	`compareTo(self $other): ?self` Returns the stronger of the two values, or null if they are equal (Yes > Maybe > No). Returns the stronger of the two values, or null if they are equal (Yes > Maybe > No).	#
`public`	`describe(): string`	#

Namespaces

Classes

Exceptions

Class PHPStan\TrinaryLogic