[dev.typeparams] cmd/compile/internal/types2: better names for things (cleanup)

- use the symbol 𝓀 (as in 𝓀niverse) instead of ⊀ to denote the set
  of all types (for better readabilty, ⊀ is hard to distinguish from
  T in some fonts)

- use isAll instead of isTop to test for the set of all types

- use allTermlist instead of topTermlist to denote the termlist
  representing all types

Change-Id: Idcb0b3398782b38653338e65173c0dbb935e430a
Reviewed-on: https://go-review.googlesource.com/c/go/+/339891
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer 2021-08-04 15:18:37 -07:00
parent 110343e4a2
commit 5aac85ad5e
8 changed files with 100 additions and 101 deletions

View file

@ -174,7 +174,7 @@ func (check *Checker) satisfies(pos syntax.Pos, targ Type, tpar *TypeParam, smap
// if iface is comparable, targ must be comparable
// TODO(gri) the error messages needs to be better, here
if iface.IsComparable() && !Comparable(targ) {
if tpar := asTypeParam(targ); tpar != nil && tpar.iface().typeSet().IsTop() {
if tpar := asTypeParam(targ); tpar != nil && tpar.iface().typeSet().IsAll() {
check.softErrorf(pos, "%s has no constraints", targ)
return false
}

View file

@ -92,7 +92,7 @@ func (t *Interface) NumMethods() int { return t.typeSet().NumMethods() }
func (t *Interface) Method(i int) *Func { return t.typeSet().Method(i) }
// Empty reports whether t is the empty interface.
func (t *Interface) Empty() bool { return t.typeSet().IsTop() }
func (t *Interface) Empty() bool { return t.typeSet().IsAll() }
// IsComparable reports whether each type in interface t's type set is comparable.
func (t *Interface) IsComparable() bool { return t.typeSet().IsComparable() }

View file

@ -13,9 +13,9 @@ import "bytes"
// normal form.
type termlist []*term
// topTermlist represents the set of all types.
// allTermlist represents the set of all types.
// It is in normal form.
var topTermlist = termlist{new(term)}
var allTermlist = termlist{new(term)}
// String prints the termlist exactly (without normalization).
func (xl termlist) String() string {
@ -45,9 +45,9 @@ func (xl termlist) isEmpty() bool {
return true
}
// isTop reports whether the termlist xl represents the set of all types.
func (xl termlist) isTop() bool {
// If there's a ⊀ (top) term, the entire list is ⊀ (top).
// isAll reports whether the termlist xl represents the set of all types.
func (xl termlist) isAll() bool {
// If there's a 𝓀 term, the entire list is 𝓀.
// If the termlist is in normal form, this requires at most
// one iteration.
for _, x := range xl {
@ -74,14 +74,14 @@ func (xl termlist) norm() termlist {
continue
}
if u1, u2 := xi.union(xj); u2 == nil {
// If we encounter a ⊀ (top) term, the entire
// list is ⊀ (top). Exit early.
// If we encounter a 𝓀 term, the entire list is 𝓀.
// Exit early.
// (Note that this is not just an optimization;
// if we continue, we may end up with a ⊀ term
// if we continue, we may end up with a 𝓀 term
// and other terms and the result would not be
// in normal form.)
if u1.typ == nil {
return topTermlist
return allTermlist
}
xi = u1
used[j] = true // xj is now unioned into xi - ignore it in future iterations
@ -92,11 +92,11 @@ func (xl termlist) norm() termlist {
return rl
}
// If the type set represented by xl is specified by a single (non-⊀) term,
// If the type set represented by xl is specified by a single (non-𝓀) term,
// structuralType returns that type. Otherwise it returns nil.
func (xl termlist) structuralType() Type {
if nl := xl.norm(); len(nl) == 1 {
return nl[0].typ // if nl.isTop() then typ is nil, which is ok
return nl[0].typ // if nl.isAll() then typ is nil, which is ok
}
return nil
}

View file

@ -21,20 +21,20 @@ func maketl(s string) termlist {
}
func TestTermlistTop(t *testing.T) {
if !topTermlist.isTop() {
t.Errorf("topTermlist is not top")
if !allTermlist.isAll() {
t.Errorf("allTermlist is not the set of all types")
}
}
func TestTermlistString(t *testing.T) {
for _, want := range []string{
"βˆ…",
"⊀",
"𝓀",
"int",
"~int",
"βˆ… βˆͺ βˆ…",
"⊀ βˆͺ ⊀",
"βˆ… βˆͺ ⊀ βˆͺ int",
"𝓀 βˆͺ 𝓀",
"βˆ… βˆͺ 𝓀 βˆͺ int",
} {
if got := maketl(want).String(); got != want {
t.Errorf("(%v).String() == %v", want, got)
@ -46,9 +46,9 @@ func TestTermlistIsEmpty(t *testing.T) {
for test, want := range map[string]bool{
"βˆ…": true,
"βˆ… βˆͺ βˆ…": true,
"βˆ… βˆͺ βˆ… βˆͺ ⊀": false,
"⊀": false,
"⊀ βˆͺ int": false,
"βˆ… βˆͺ βˆ… βˆͺ 𝓀": false,
"𝓀": false,
"𝓀 βˆͺ int": false,
} {
xl := maketl(test)
got := xl.isEmpty()
@ -58,19 +58,19 @@ func TestTermlistIsEmpty(t *testing.T) {
}
}
func TestTermlistIsTop(t *testing.T) {
func TestTermlistIsAll(t *testing.T) {
for test, want := range map[string]bool{
"βˆ…": false,
"βˆ… βˆͺ βˆ…": false,
"int βˆͺ ~string": false,
"βˆ… βˆͺ βˆ… βˆͺ ⊀": true,
"⊀": true,
"⊀ βˆͺ int": true,
"βˆ… βˆͺ βˆ… βˆͺ 𝓀": true,
"𝓀": true,
"𝓀 βˆͺ int": true,
} {
xl := maketl(test)
got := xl.isTop()
got := xl.isAll()
if got != want {
t.Errorf("(%v).isTop() == %v; want %v", test, got, want)
t.Errorf("(%v).isAll() == %v; want %v", test, got, want)
}
}
}
@ -82,10 +82,10 @@ func TestTermlistNorm(t *testing.T) {
{"βˆ…", "βˆ…"},
{"βˆ… βˆͺ βˆ…", "βˆ…"},
{"βˆ… βˆͺ int", "int"},
{"⊀ βˆͺ int", "⊀"},
{"𝓀 βˆͺ int", "𝓀"},
{"~int βˆͺ int", "~int"},
{"int βˆͺ ~string βˆͺ int", "int βˆͺ ~string"},
{"~int βˆͺ string βˆͺ ⊀ βˆͺ ~string βˆͺ int", "⊀"},
{"~int βˆͺ string βˆͺ 𝓀 βˆͺ ~string βˆͺ int", "𝓀"},
} {
xl := maketl(test.xl)
got := maketl(test.xl).norm()
@ -106,7 +106,7 @@ func TestTermlistStructuralType(t *testing.T) {
for test, want := range map[string]string{
"βˆ…": "nil",
"⊀": "nil",
"𝓀": "nil",
"int": "int",
"~int": "int",
"~int βˆͺ string": "nil",
@ -128,15 +128,15 @@ func TestTermlistUnion(t *testing.T) {
}{
{"βˆ…", "βˆ…", "βˆ…"},
{"βˆ…", "⊀", "⊀"},
{"βˆ…", "𝓀", "𝓀"},
{"βˆ…", "int", "int"},
{"⊀", "~int", "⊀"},
{"𝓀", "~int", "𝓀"},
{"int", "~int", "~int"},
{"int", "string", "int βˆͺ string"},
{"int βˆͺ string", "~string", "int βˆͺ ~string"},
{"~int βˆͺ string", "~string βˆͺ int", "~int βˆͺ ~string"},
{"~int βˆͺ string βˆͺ βˆ…", "~string βˆͺ int", "~int βˆͺ ~string"},
{"~int βˆͺ string βˆͺ ⊀", "~string βˆͺ int", "⊀"},
{"~int βˆͺ string βˆͺ 𝓀", "~string βˆͺ int", "𝓀"},
} {
xl := maketl(test.xl)
yl := maketl(test.yl)
@ -153,15 +153,15 @@ func TestTermlistIntersect(t *testing.T) {
}{
{"βˆ…", "βˆ…", "βˆ…"},
{"βˆ…", "⊀", "βˆ…"},
{"βˆ…", "𝓀", "βˆ…"},
{"βˆ…", "int", "βˆ…"},
{"⊀", "~int", "~int"},
{"𝓀", "~int", "~int"},
{"int", "~int", "int"},
{"int", "string", "βˆ…"},
{"int βˆͺ string", "~string", "string"},
{"~int βˆͺ string", "~string βˆͺ int", "int βˆͺ string"},
{"~int βˆͺ string βˆͺ βˆ…", "~string βˆͺ int", "int βˆͺ string"},
{"~int βˆͺ string βˆͺ ⊀", "~string βˆͺ int", "int βˆͺ ~string"},
{"~int βˆͺ string βˆͺ 𝓀", "~string βˆͺ int", "int βˆͺ ~string"},
} {
xl := maketl(test.xl)
yl := maketl(test.yl)
@ -178,10 +178,10 @@ func TestTermlistEqual(t *testing.T) {
want bool
}{
{"βˆ…", "βˆ…", true},
{"βˆ…", "⊀", false},
{"⊀", "⊀", true},
{"⊀ βˆͺ int", "⊀", true},
{"⊀ βˆͺ int", "string βˆͺ ⊀", true},
{"βˆ…", "𝓀", false},
{"𝓀", "𝓀", true},
{"𝓀 βˆͺ int", "𝓀", true},
{"𝓀 βˆͺ int", "string βˆͺ 𝓀", true},
{"int βˆͺ ~string", "string βˆͺ int", false},
{"int βˆͺ ~string βˆͺ βˆ…", "string βˆͺ int βˆͺ ~string", true},
} {
@ -200,14 +200,14 @@ func TestTermlistIncludes(t *testing.T) {
want bool
}{
{"βˆ…", "int", false},
{"⊀", "int", true},
{"𝓀", "int", true},
{"~int", "int", true},
{"int", "string", false},
{"~int", "string", false},
{"int βˆͺ string", "string", true},
{"~int βˆͺ string", "int", true},
{"~int βˆͺ string βˆͺ βˆ…", "string", true},
{"~string βˆͺ βˆ… βˆͺ ⊀", "int", true},
{"~string βˆͺ βˆ… βˆͺ 𝓀", "int", true},
} {
xl := maketl(test.xl)
yl := testTerm(test.typ).typ
@ -224,12 +224,12 @@ func TestTermlistSupersetOf(t *testing.T) {
want bool
}{
{"βˆ…", "βˆ…", true},
{"βˆ…", "⊀", false},
{"βˆ…", "𝓀", false},
{"βˆ…", "int", false},
{"⊀", "βˆ…", true},
{"⊀", "⊀", true},
{"⊀", "int", true},
{"⊀", "~int", true},
{"𝓀", "βˆ…", true},
{"𝓀", "𝓀", true},
{"𝓀", "int", true},
{"𝓀", "~int", true},
{"~int", "int", true},
{"~int", "~int", true},
{"int", "~int", false},
@ -239,7 +239,7 @@ func TestTermlistSupersetOf(t *testing.T) {
{"int βˆͺ string", "~string", false},
{"~int βˆͺ string", "int", true},
{"~int βˆͺ string βˆͺ βˆ…", "string", true},
{"~string βˆͺ βˆ… βˆͺ ⊀", "int", true},
{"~string βˆͺ βˆ… βˆͺ 𝓀", "int", true},
} {
xl := maketl(test.xl)
y := testTerm(test.typ)
@ -256,16 +256,16 @@ func TestTermlistSubsetOf(t *testing.T) {
want bool
}{
{"βˆ…", "βˆ…", true},
{"βˆ…", "⊀", true},
{"⊀", "βˆ…", false},
{"⊀", "⊀", true},
{"βˆ…", "𝓀", true},
{"𝓀", "βˆ…", false},
{"𝓀", "𝓀", true},
{"int", "int βˆͺ string", true},
{"~int", "int βˆͺ string", false},
{"~int", "string βˆͺ string βˆͺ int βˆͺ ~int", true},
{"int βˆͺ string", "string", false},
{"int βˆͺ string", "string βˆͺ int", true},
{"int βˆͺ ~string", "string βˆͺ int", false},
{"int βˆͺ ~string", "string βˆͺ int βˆͺ ⊀", true},
{"int βˆͺ ~string", "string βˆͺ int βˆͺ 𝓀", true},
{"int βˆͺ ~string", "string βˆͺ int βˆͺ βˆ… βˆͺ string", false},
} {
xl := maketl(test.xl)

View file

@ -25,17 +25,19 @@ type TypeSet struct {
// IsEmpty reports whether type set s is the empty set.
func (s *TypeSet) IsEmpty() bool { return s.terms.isEmpty() }
// IsTop reports whether type set s is the set of all types (corresponding to the empty interface).
func (s *TypeSet) IsTop() bool { return !s.comparable && len(s.methods) == 0 && s.terms.isTop() }
// IsAll reports whether type set s is the set of all types (corresponding to the empty interface).
func (s *TypeSet) IsAll() bool {
return !s.comparable && len(s.methods) == 0 && s.terms.isAll()
}
// TODO(gri) IsMethodSet is not a great name for this predicate. Find a better one.
// IsMethodSet reports whether the type set s is described by a single set of methods.
func (s *TypeSet) IsMethodSet() bool { return !s.comparable && s.terms.isTop() }
func (s *TypeSet) IsMethodSet() bool { return !s.comparable && s.terms.isAll() }
// IsComparable reports whether each type in the set is comparable.
func (s *TypeSet) IsComparable() bool {
if s.terms.isTop() {
if s.terms.isAll() {
return s.comparable
}
return s.is(func(t *term) bool {
@ -67,8 +69,8 @@ func (s *TypeSet) String() string {
switch {
case s.IsEmpty():
return "βˆ…"
case s.IsTop():
return "⊀"
case s.IsAll():
return "𝓀"
}
hasMethods := len(s.methods) > 0
@ -103,7 +105,7 @@ func (s *TypeSet) String() string {
// ----------------------------------------------------------------------------
// Implementation
func (s *TypeSet) hasTerms() bool { return !s.terms.isTop() }
func (s *TypeSet) hasTerms() bool { return !s.terms.isAll() }
func (s *TypeSet) structuralType() Type { return s.terms.structuralType() }
func (s *TypeSet) includes(t Type) bool { return s.terms.includes(t) }
func (s1 *TypeSet) subsetOf(s2 *TypeSet) bool { return s1.terms.subsetOf(s2.terms) }
@ -156,7 +158,7 @@ func (s *TypeSet) underIs(f func(Type) bool) bool {
}
// topTypeSet may be used as type set for the empty interface.
var topTypeSet = TypeSet{terms: topTermlist}
var topTypeSet = TypeSet{terms: allTermlist}
// computeInterfaceTypeSet may be called with check == nil.
func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
@ -195,7 +197,7 @@ func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *T
// have valid interfaces. Mark the interface as complete to avoid
// infinite recursion if the validType check occurs later for some
// reason.
ityp.tset = &TypeSet{terms: topTermlist} // TODO(gri) is this sufficient?
ityp.tset = &TypeSet{terms: allTermlist} // TODO(gri) is this sufficient?
// Methods of embedded interfaces are collected unchanged; i.e., the identity
// of a method I.m's Func Object of an interface I is the same as that of
@ -256,7 +258,7 @@ func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *T
}
// collect embedded elements
var allTerms = topTermlist
var allTerms = allTermlist
for i, typ := range ityp.embeddeds {
// The embedding position is nil for imported interfaces
// and also for interface copies after substitution (but

View file

@ -4,13 +4,10 @@
package types2
// TODO(gri) use a different symbol instead of ⊀ for the set of all types
// (⊀ is hard to distinguish from T in some fonts)
// A term describes elementary type sets:
//
// βˆ…: (*term)(nil) == βˆ… // set of no types (empty set)
// ⊀: &term{} == ⊀ // set of all types
// 𝓀: &term{} == 𝓀 // set of all types (𝓀niverse)
// T: &term{false, T} == {T} // set of type T
// ~t: &term{true, t} == {t' | under(t') == t} // set of types with underlying type t
//
@ -24,7 +21,7 @@ func (x *term) String() string {
case x == nil:
return "βˆ…"
case x.typ == nil:
return "⊀"
return "𝓀"
case x.tilde:
return "~" + x.typ.String()
default:
@ -41,7 +38,7 @@ func (x *term) equal(y *term) bool {
case x.typ == nil || y.typ == nil:
return x.typ == y.typ
}
// βˆ… βŠ‚ x, y βŠ‚ ⊀
// βˆ… βŠ‚ x, y βŠ‚ 𝓀
return x.tilde == y.tilde && Identical(x.typ, y.typ)
}
@ -57,11 +54,11 @@ func (x *term) union(y *term) (_, _ *term) {
case y == nil:
return x, nil // x βˆͺ βˆ… == x
case x.typ == nil:
return x, nil // ⊀ βˆͺ y == ⊀
return x, nil // 𝓀 βˆͺ y == 𝓀
case y.typ == nil:
return y, nil // x βˆͺ ⊀ == ⊀
return y, nil // x βˆͺ 𝓀 == 𝓀
}
// βˆ… βŠ‚ x, y βŠ‚ ⊀
// βˆ… βŠ‚ x, y βŠ‚ 𝓀
if x.disjoint(y) {
return x, y // x βˆͺ y == (x, y) if x ∩ y == βˆ…
@ -85,11 +82,11 @@ func (x *term) intersect(y *term) *term {
case x == nil || y == nil:
return nil // βˆ… ∩ y == βˆ… and ∩ βˆ… == βˆ…
case x.typ == nil:
return y // ⊀ ∩ y == y
return y // 𝓀 ∩ y == y
case y.typ == nil:
return x // x ∩ ⊀ == x
return x // x ∩ 𝓀 == x
}
// βˆ… βŠ‚ x, y βŠ‚ ⊀
// βˆ… βŠ‚ x, y βŠ‚ 𝓀
if x.disjoint(y) {
return nil // x ∩ y == βˆ… if x ∩ y == βˆ…
@ -113,9 +110,9 @@ func (x *term) includes(t Type) bool {
case x == nil:
return false // t ∈ βˆ… == false
case x.typ == nil:
return true // t ∈ ⊀ == true
return true // t ∈ 𝓀 == true
}
// βˆ… βŠ‚ x βŠ‚ ⊀
// βˆ… βŠ‚ x βŠ‚ 𝓀
u := t
if x.tilde {
@ -133,11 +130,11 @@ func (x *term) subsetOf(y *term) bool {
case y == nil:
return false // x βŠ† βˆ… == false since x != βˆ…
case y.typ == nil:
return true // x βŠ† ⊀ == true
return true // x βŠ† 𝓀 == true
case x.typ == nil:
return false // ⊀ βŠ† y == false since y != ⊀
return false // 𝓀 βŠ† y == false since y != 𝓀
}
// βˆ… βŠ‚ x, y βŠ‚ ⊀
// βˆ… βŠ‚ x, y βŠ‚ 𝓀
if x.disjoint(y) {
return false // x βŠ† y == false if x ∩ y == βˆ…

View file

@ -11,7 +11,7 @@ import (
var testTerms = map[string]*term{
"βˆ…": nil,
"⊀": {},
"𝓀": {},
"int": {false, Typ[Int]},
"~int": {true, Typ[Int]},
"string": {false, Typ[String]},
@ -46,14 +46,14 @@ func testTerm(name string) *term {
func TestTermEqual(t *testing.T) {
for _, test := range []string{
"βˆ… βˆ… T",
"⊀ ⊀ T",
"𝓀 𝓀 T",
"int int T",
"~int ~int T",
"βˆ… ⊀ F",
"βˆ… 𝓀 F",
"βˆ… int F",
"βˆ… ~int F",
"⊀ int F",
"⊀ ~int F",
"𝓀 int F",
"𝓀 ~int F",
"int ~int F",
} {
args := split(test, 3)
@ -74,12 +74,12 @@ func TestTermEqual(t *testing.T) {
func TestTermUnion(t *testing.T) {
for _, test := range []string{
"βˆ… βˆ… βˆ… βˆ…",
"βˆ… ⊀ ⊀ βˆ…",
"βˆ… 𝓀 𝓀 βˆ…",
"βˆ… int int βˆ…",
"βˆ… ~int ~int βˆ…",
"⊀ ⊀ ⊀ βˆ…",
"⊀ int ⊀ βˆ…",
"⊀ ~int ⊀ βˆ…",
"𝓀 𝓀 𝓀 βˆ…",
"𝓀 int 𝓀 βˆ…",
"𝓀 ~int 𝓀 βˆ…",
"int int int βˆ…",
"int ~int ~int βˆ…",
"int string int string",
@ -87,11 +87,11 @@ func TestTermUnion(t *testing.T) {
"~int ~string ~int ~string",
// union is symmetric, but the result order isn't - repeat symmetric cases explictly
"⊀ βˆ… ⊀ βˆ…",
"𝓀 βˆ… 𝓀 βˆ…",
"int βˆ… int βˆ…",
"~int βˆ… ~int βˆ…",
"int ⊀ ⊀ βˆ…",
"~int ⊀ ⊀ βˆ…",
"int 𝓀 𝓀 βˆ…",
"~int 𝓀 𝓀 βˆ…",
"~int int ~int βˆ…",
"string int string int",
"~string int ~string int",
@ -111,12 +111,12 @@ func TestTermUnion(t *testing.T) {
func TestTermIntersection(t *testing.T) {
for _, test := range []string{
"βˆ… βˆ… βˆ…",
"βˆ… ⊀ βˆ…",
"βˆ… 𝓀 βˆ…",
"βˆ… int βˆ…",
"βˆ… ~int βˆ…",
"⊀ ⊀ ⊀",
"⊀ int int",
"⊀ ~int ~int",
"𝓀 𝓀 𝓀",
"𝓀 int int",
"𝓀 ~int ~int",
"int int int",
"int ~int int",
"int string βˆ…",
@ -141,7 +141,7 @@ func TestTermIntersection(t *testing.T) {
func TestTermIncludes(t *testing.T) {
for _, test := range []string{
"βˆ… int F",
"⊀ int T",
"𝓀 int T",
"int int T",
"~int int T",
"string int F",
@ -160,14 +160,14 @@ func TestTermIncludes(t *testing.T) {
func TestTermSubsetOf(t *testing.T) {
for _, test := range []string{
"βˆ… βˆ… T",
"⊀ ⊀ T",
"𝓀 𝓀 T",
"int int T",
"~int ~int T",
"βˆ… ⊀ T",
"βˆ… 𝓀 T",
"βˆ… int T",
"βˆ… ~int T",
"⊀ int F",
"⊀ ~int F",
"𝓀 int F",
"𝓀 ~int F",
"int ~int T",
} {
args := split(test, 3)

View file

@ -99,7 +99,7 @@ func defPredeclaredTypes() {
{
obj := NewTypeName(nopos, nil, "comparable", nil)
obj.setColor(black)
ityp := &Interface{obj, nil, nil, nil, true, &TypeSet{true, nil, topTermlist}}
ityp := &Interface{obj, nil, nil, nil, true, &TypeSet{true, nil, allTermlist}}
NewNamed(obj, ityp, nil)
def(obj)
}