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https://github.com/golang/go
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70d54df4f6
For Builtin ops, we currently stay with using the old typechecker to transform the call to a more specific expression and possibly use more specific ops. However, for a bunch of the ops, we delay calling the old typechecker if any of the args have type params, for a variety of reasons. In the near future, we will start creating separate functions that do the same transformations as the old typechecker for calls, builtins, indexing, comparisons, etc. These functions can then be called at noder time for nodes with no type params, and at stenciling time for nodes with type params. Remove unnecessary calls to types1 typechecker for most kinds of statements (still need it for SendStmt, AssignStmt, ReturnStmt, and SelectStmt). In particular, we don't need it for RangeStmt, and this avoids some complaints by the types1 typechecker on generic code. Other small changes: - Fix check on whether to delay calling types1-typechecker on type conversions. Should check if HasTParam is true, rather than if the type is directly a TYPEPARAM. - Don't call types1-typechecker on an indexing operation if the left operand has a typeparam in its type and is not obviously a TMAP, TSLICE, or TARRAY. As above, we will eventually have to create a new function that can do the required transformations (for complicated cases) at noder time or stenciling time. - Copy n.BuiltinOp in subster.node() - The complex arithmetic example in absdiff.go now works. - Added new tests double.go and append.go - Added new example with a new() call in settable.go Change-Id: I8f377afb6126cab1826bd3c2732aa8cdf1f7e0b4 Reviewed-on: https://go-review.googlesource.com/c/go/+/301951 Run-TryBot: Dan Scales <danscales@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Dan Scales <danscales@google.com> Trust: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>
99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
// run -gcflags=-G=3
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// Copyright 2020 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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"math"
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)
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type Numeric interface {
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type int, int8, int16, int32, int64,
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uint, uint8, uint16, uint32, uint64, uintptr,
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float32, float64,
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complex64, complex128
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}
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// numericAbs matches numeric types with an Abs method.
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type numericAbs[T any] interface {
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Numeric
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Abs() T
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}
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// AbsDifference computes the absolute value of the difference of
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// a and b, where the absolute value is determined by the Abs method.
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func absDifference[T numericAbs[T]](a, b T) T {
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d := a - b
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return d.Abs()
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}
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// orderedNumeric matches numeric types that support the < operator.
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type orderedNumeric interface {
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type int, int8, int16, int32, int64,
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uint, uint8, uint16, uint32, uint64, uintptr,
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float32, float64
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}
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// Complex matches the two complex types, which do not have a < operator.
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type Complex interface {
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type complex64, complex128
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}
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// orderedAbs is a helper type that defines an Abs method for
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// ordered numeric types.
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type orderedAbs[T orderedNumeric] T
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func (a orderedAbs[T]) Abs() orderedAbs[T] {
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// TODO(danscales): orderedAbs[T] conversion shouldn't be needed
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if a < orderedAbs[T](0) {
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return -a
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}
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return a
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}
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// complexAbs is a helper type that defines an Abs method for
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// complex types.
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type complexAbs[T Complex] T
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func (a complexAbs[T]) Abs() complexAbs[T] {
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r := float64(real(a))
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i := float64(imag(a))
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d := math.Sqrt(r * r + i * i)
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return complexAbs[T](complex(d, 0))
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}
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// OrderedAbsDifference returns the absolute value of the difference
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// between a and b, where a and b are of an ordered type.
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func orderedAbsDifference[T orderedNumeric](a, b T) T {
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return T(absDifference(orderedAbs[T](a), orderedAbs[T](b)))
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}
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// ComplexAbsDifference returns the absolute value of the difference
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// between a and b, where a and b are of a complex type.
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func complexAbsDifference[T Complex](a, b T) T {
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return T(absDifference(complexAbs[T](a), complexAbs[T](b)))
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}
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func main() {
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if got, want := orderedAbsDifference(1.0, -2.0), 3.0; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := orderedAbsDifference(-1.0, 2.0), 3.0; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := orderedAbsDifference(-20, 15), 35; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := complexAbsDifference(5.0 + 2.0i, 2.0 - 2.0i), 5+0i; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := complexAbsDifference(2.0 - 2.0i, 5.0 + 2.0i), 5+0i; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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}
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