62df06c385
This PR adds Merge() helper function for choosing which value of two pointers to use during a larger merge operation. If 'next' is not nil, use that value, otherwise use the 'previous' value.
47 lines
1 KiB
Go
47 lines
1 KiB
Go
// Package pointer provides helper functions related to Go pointers.
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package pointer
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import (
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"golang.org/x/exp/constraints"
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)
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// Primitive represents basic types that are safe to do basic comparisons by
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// pointer dereference (checking nullity first).
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type Primitive interface {
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constraints.Ordered | bool
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}
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// Of returns a pointer to a.
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func Of[A any](a A) *A {
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return &a
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}
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// Copy returns a new pointer to a.
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func Copy[A any](a *A) *A {
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if a == nil {
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return nil
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}
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na := *a
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return &na
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}
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// Merge will return Copy(next) if next is not nil, otherwise return Copy(previous).
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func Merge[P Primitive](previous, next *P) *P {
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if next != nil {
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return Copy(next)
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}
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return Copy(previous)
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}
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// Eq returns whether a and b are equal in underlying value.
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//
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// May only be used on pointers to primitive types, where the comparison is
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// guaranteed to be sensible. For complex types (i.e. structs) consider implementing
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// an Equal method.
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func Eq[P Primitive](a, b *P) bool {
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if a == nil || b == nil {
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return a == b
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}
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return *a == *b
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}
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