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Struct `std.checkedint.ProperCompare`

Hook that provides arithmetically correct comparisons for equality and ordering. Comparing an object of type Checked!(X, ProperCompare) against another integral (for equality or ordering) ensures that no surprising conversions from signed to unsigned integral occur before the comparison. Using Checked!(X, ProperCompare) on either side of a comparison for equality against a floating-point number makes sure the integral can be properly converted to the floating point type, thus making sure equality is transitive.


						
				struct ProperCompare
				;

Methods

Name Description

hookOpCmp (lhs, rhs) Hook for <, <=, >, and >= that ensures comparison against integral values has the behavior expected by the usual arithmetic rules. The built-in semantics yield surprising behavior when comparing signed values against unsigned values, for example 0u < -1. The call hookOpCmp(x, y) returns -1 if and only if x is smaller than y in abstract arithmetic sense.

hookOpEquals (lhs, rhs) Hook for == and != that ensures comparison against integral values has the behavior expected by the usual arithmetic rules. The built-in semantics yield surprising behavior when comparing signed values against unsigned values for equality, for example uint.max == -1 or -1_294_967_296 == 3_000_000_000u. The call hookOpEquals(x, y) returns true if and only if x and y represent the same arithmetic number.

Name	Description
`hookOpCmp` (lhs, rhs)	Hook for `<`, `<=`, `>`, and `>=` that ensures comparison against integral values has the behavior expected by the usual arithmetic rules. The built-in semantics yield surprising behavior when comparing signed values against unsigned values, for example `0u < -1`. The call `hookOpCmp(x, y)` returns `-1` if and only if `x` is smaller than `y` in abstract arithmetic sense.
`hookOpEquals` (lhs, rhs)	Hook for `==` and `!=` that ensures comparison against integral values has the behavior expected by the usual arithmetic rules. The built-in semantics yield surprising behavior when comparing signed values against unsigned values for equality, for example `uint.max == -1` or `-1_294_967_296 == 3_000_000_000u`. The call `hookOpEquals(x, y)` returns `true` if and only if `x` and `y` represent the same arithmetic number.

Example

alias opEqualsProper = ProperCompare.hookOpEquals;
assert(opEqualsProper(42, 42));
assert(opEqualsProper(42.0, 42.0));
assert(opEqualsProper(42u, 42));
assert(opEqualsProper(42, 42u));
writeln(-1); // 4294967295u
assert(!opEqualsProper(-1, 4294967295u));
assert(!opEqualsProper(const uint(-1), -1));
assert(!opEqualsProper(uint(-1), -1.0));
writeln(3_000_000_000U); // -1_294_967_296
assert(!opEqualsProper(3_000_000_000U, -1_294_967_296));

API Documentation

Struct `std.checkedint.ProperCompare`

Methods

Example

Authors

License

API Documentation

Struct std.checkedint.ProperCompare

Methods

Example

Authors

License

Struct `std.checkedint.ProperCompare`