mirror of
https://github.com/golang/go
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63 lines
1.2 KiB
Go
63 lines
1.2 KiB
Go
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// run -gcflags=-G=3
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"fmt"
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)
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// Numeric expresses a type constraint satisfied by any numeric type.
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type Numeric interface {
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~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 |
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~int | ~int8 | ~int16 | ~int32 | ~int64 |
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~float32 | ~float64 |
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~complex64 | ~complex128
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}
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// Sum returns the sum of the provided arguments.
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func Sum[T Numeric](args ...T) T {
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var sum T
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for i := 0; i < len(args); i++ {
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sum += args[i]
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}
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return sum
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}
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// Ledger is an identifiable, financial record.
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type Ledger[T ~string, K Numeric] struct {
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// ID identifies the ledger.
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ID T
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// Amounts is a list of monies associated with this ledger.
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Amounts []K
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// SumFn is a function that can be used to sum the amounts
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// in this ledger.
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SumFn func(...K) K
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}
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func PrintLedger[
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T ~string,
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K Numeric,
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L ~struct {
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ID T
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Amounts []K
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SumFn func(...K) K
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},
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](l L) {
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fmt.Printf("%s has a sum of %v\n", l.ID, l.SumFn(l.Amounts...))
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}
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func main() {
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PrintLedger(Ledger[string, int]{
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ID: "fake",
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Amounts: []int{1, 2, 3},
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SumFn: Sum[int],
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})
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}
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