Add Hash to Value interface.

edit/api.go

@@ -8,9 +8,11 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"unsafe"
 
 	"github.com/elves/elvish/edit/ui"
 	"github.com/elves/elvish/eval"
+	"github.com/xiaq/persistent/hash"
 )
 
 // This file implements types and functions for interactions with the
@@ -41,6 +43,10 @@ func (bf *BuiltinFn) Equal(a interface{}) bool {
 	return bf == a
 }
 
+func (bf *BuiltinFn) Hash() uint32 {
+	return hash.Pointer(unsafe.Pointer(bf))
+}
+
 // Repr returns the representation of a builtin function as a variable name.
 func (bf *BuiltinFn) Repr(int) string {
 	return "$" + bf.name

edit/arg_completers.go

@@ -2,8 +2,10 @@ package edit
 
 import (
 	"errors"
+	"unsafe"
 
 	"github.com/elves/elvish/eval"
+	"github.com/xiaq/persistent/hash"
 )
 
 // For an overview of completion, see the comment in completers.go.
@@ -123,6 +125,10 @@ func (bac *builtinArgCompleter) Equal(a interface{}) bool {
 	return bac == a
 }
 
+func (bac *builtinArgCompleter) Hash() uint32 {
+	return hash.Pointer(unsafe.Pointer(bac))
+}
+
 func (bac *builtinArgCompleter) Repr(int) string {
 	return "$edit:&" + bac.name
 }

edit/binding.go

@@ -4,6 +4,7 @@ import (
 	"github.com/elves/elvish/edit/ui"
 	"github.com/elves/elvish/eval"
 	"github.com/elves/elvish/parse"
+	"github.com/xiaq/persistent/hash"
 )
 
 func getBinding(mode string, k ui.Key) eval.CallableValue {
@@ -45,6 +46,17 @@ func (bt BindingTable) Equal(a interface{}) bool {
 	return true
 }
 
+func (bt BindingTable) Hash() uint32 {
+	h := hash.DJBInit
+	for k, v := range bt.inner {
+		// TODO(xiaq): Use a more efficient implementation to derive a hash from
+		// ui.Key.
+		h = hash.DJBCombine(h, hash.String(k.String()))
+		h = hash.DJBCombine(h, v.Hash())
+	}
+	return h
+}
+
 // Repr returns the representation of the binding table as if it were an
 // ordinary map.
 func (bt BindingTable) Repr(indent int) string {

edit/candidate.go

@@ -8,6 +8,7 @@ import (
 	"github.com/elves/elvish/edit/ui"
 	"github.com/elves/elvish/eval"
 	"github.com/elves/elvish/parse"
+	"github.com/xiaq/persistent/hash"
 )
 
 type candidate struct {
@@ -29,10 +30,11 @@ func (cs rawCandidates) Swap(i, j int)      { cs[i], cs[j] = cs[j], cs[i] }
 func (cs rawCandidates) Less(i, j int) bool { return cs[i].text() < cs[j].text() }
 
 // plainCandidate is a minimal implementation of rawCandidate.
-type plainCandidate string
+type plainCandidate eval.String
 
 func (plainCandidate) Kind() string               { return "string" }
 func (p plainCandidate) Equal(a interface{}) bool { return p == a }
+func (p plainCandidate) Hash() uint32             { return hash.String(string(p)) }
 func (p plainCandidate) Repr(l int) string        { return eval.String(p).Repr(l) }
 func (p plainCandidate) text() string             { return string(p) }
 
@@ -47,6 +49,7 @@ type noQuoteCandidate string
 
 func (noQuoteCandidate) Kind() string                { return "string" }
 func (nq noQuoteCandidate) Equal(a interface{}) bool { return nq == a }
+func (nq noQuoteCandidate) Hash() uint32             { return hash.String(string(nq)) }
 func (nq noQuoteCandidate) Repr(l int) string        { return eval.String(nq).Repr(l) }
 func (nq noQuoteCandidate) text() string             { return string(nq) }
 
@@ -71,6 +74,15 @@ func (c *complexCandidate) Equal(a interface{}) bool {
 	return ok && c.stem == rhs.stem && c.codeSuffix == rhs.codeSuffix && c.displaySuffix == rhs.displaySuffix && c.style.Eq(rhs.style)
 }
 
+func (c *complexCandidate) Hash() uint32 {
+	h := hash.DJBInit
+	h = hash.DJBCombine(h, hash.String(c.stem))
+	h = hash.DJBCombine(h, hash.String(c.codeSuffix))
+	h = hash.DJBCombine(h, hash.String(c.displaySuffix))
+	h = hash.DJBCombine(h, c.style.Hash())
+	return h
+}
+
 func (c *complexCandidate) Repr(indent int) string {
 	// TODO(xiaq): Pretty-print when indent >= 0
 	return fmt.Sprintf("(edit:complex-candidate %s &code-suffix=%s &display-suffix=%s style=%s)",

edit/history_value.go

@@ -25,6 +25,12 @@ func (hv History) Equal(a interface{}) bool {
 	return ok
 }
 
+func (hv History) Hash() uint32 {
+	// TODO(xiaq): Make a global registry of singleton hashes to avoid
+	// collision.
+	return 100
+}
+
 func (hv History) Repr(int) string {
 	return "$le:history"
 }

edit/ui/styled.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 
 	"github.com/elves/elvish/parse"
+	"github.com/xiaq/persistent/hash"
 )
 
 // Styled is a piece of text with style.
@@ -72,6 +73,13 @@ func (s *Styled) Equal(a interface{}) bool {
 	return s.Text == rhs.Text && s.Styles.Eq(rhs.Styles)
 }
 
+func (s *Styled) Hash() uint32 {
+	h := hash.DJBInit
+	h = hash.DJBCombine(h, hash.String(s.Text))
+	h = hash.DJBCombine(h, s.Styles.Hash())
+	return h
+}
+
 func (s *Styled) String() string {
 	return "\033[" + s.Styles.String() + "m" + s.Text + "\033[m"
 }
@@ -94,6 +102,14 @@ func (ss Styles) Eq(rhs Styles) bool {
 	return true
 }
 
+func (ss Styles) Hash() uint32 {
+	h := hash.DJBInit
+	for _, s := range ss {
+		h = hash.DJBCombine(h, hash.String(s))
+	}
+	return h
+}
+
 func JoinStyles(so Styles, st ...Styles) Styles {
 	for _, v := range st {
 		so = append(so, v...)

eval/bool.go

@@ -11,6 +11,13 @@ func (b Bool) Equal(rhs interface{}) bool {
 	return b == rhs
 }
 
+func (b Bool) Hash() uint32 {
+	if b {
+		return 1
+	}
+	return 0
+}
+
 func (b Bool) Repr(int) string {
 	if b {
 		return "$true"

eval/builtin_fn.go

@@ -23,11 +23,13 @@ import (
 	"syscall"
 	"time"
 	"unicode/utf8"
+	"unsafe"
 
 	"github.com/elves/elvish/parse"
 	"github.com/elves/elvish/store/storedefs"
 	"github.com/elves/elvish/sys"
 	"github.com/elves/elvish/util"
+	"github.com/xiaq/persistent/hash"
 )
 
 var builtinFns []*BuiltinFn
@@ -52,6 +54,10 @@ func (b *BuiltinFn) Equal(rhs interface{}) bool {
 	return b == rhs
 }
 
+func (b *BuiltinFn) Hash() uint32 {
+	return hash.Pointer(unsafe.Pointer(b))
+}
+
 // Repr returns an opaque representation "<builtin xxx>".
 func (b *BuiltinFn) Repr(int) string {
 	return "<builtin " + b.Name + ">"

eval/closure.go

@@ -3,6 +3,9 @@ package eval
 import (
 	"errors"
 	"fmt"
+	"unsafe"
+
+	"github.com/xiaq/persistent/hash"
 )
 
 // ErrArityMismatch is thrown by a closure when the number of arguments the user
@@ -36,6 +39,10 @@ func (c *Closure) Equal(rhs interface{}) bool {
 	return c == rhs
 }
 
+func (c *Closure) Hash() uint32 {
+	return hash.Pointer(unsafe.Pointer(c))
+}
+
 // Repr returns an opaque representation "<closure 0x23333333>".
 func (c *Closure) Repr(int) string {
 	return fmt.Sprintf("<closure %p>", c)

eval/env_path_list.go

@@ -5,6 +5,8 @@ import (
 	"os"
 	"strings"
 	"sync"
+
+	"github.com/xiaq/persistent/hash"
 )
 
 // Errors
@@ -70,6 +72,14 @@ func (epl *EnvPathList) Equal(a interface{}) bool {
 	return epl == a || eqListLike(epl, a)
 }
 
+func (epl *EnvPathList) Hash() uint32 {
+	h := hash.DJBInit
+	for _, p := range epl.get() {
+		h = hash.DJBCombine(h, hash.String(p))
+	}
+	return h
+}
+
 // Repr returns the representation of an EnvPathList, as if it were an ordinary
 // list.
 func (epl *EnvPathList) Repr(indent int) string {

eval/exception.go

@@ -6,9 +6,11 @@ import (
 	"strconv"
 	"strings"
 	"syscall"
+	"unsafe"
 
 	"github.com/elves/elvish/parse"
 	"github.com/elves/elvish/util"
+	"github.com/xiaq/persistent/hash"
 )
 
 // Exception represents an elvish exception. It is both a Value accessible to
@@ -76,6 +78,10 @@ func (exc *Exception) Equal(rhs interface{}) bool {
 	return exc == rhs
 }
 
+func (exc *Exception) Hash() uint32 {
+	return hash.Pointer(unsafe.Pointer(exc))
+}
+
 func (exc *Exception) Bool() bool {
 	return exc.Cause == nil
 }

eval/external_cmd.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/elves/elvish/parse"
 	"github.com/elves/elvish/util"
+	"github.com/xiaq/persistent/hash"
 )
 
 // FdNil is a special impossible fd value used for "close fd" in
@@ -32,6 +33,10 @@ func (e ExternalCmd) Equal(a interface{}) bool {
 	return e == a
 }
 
+func (e ExternalCmd) Hash() uint32 {
+	return hash.String(e.Name)
+}
+
 func (e ExternalCmd) Repr(int) string {
 	return "<external " + parse.Quote(e.Name) + ">"
 }

eval/file.go

@@ -5,6 +5,7 @@ import (
 	"os"
 
 	"github.com/elves/elvish/parse"
+	"github.com/xiaq/persistent/hash"
 )
 
 type File struct {
@@ -21,6 +22,10 @@ func (f File) Equal(rhs interface{}) bool {
 	return f == rhs
 }
 
+func (f File) Hash() uint32 {
+	return hash.UIntPtr(f.inner.Fd())
+}
+
 func (f File) Repr(int) string {
 	return fmt.Sprintf("<file{%s %p}>", parse.Quote(f.inner.Name()), f.inner)
 }

eval/glob.go

@@ -64,6 +64,11 @@ func (gp GlobPattern) Equal(a interface{}) bool {
 	return reflect.DeepEqual(gp, a)
 }
 
+func (gp GlobPattern) Hash() uint32 {
+	// GlobPattern is not a first-class value.
+	return 0
+}
+
 func (gp GlobPattern) Repr(int) string {
 	return fmt.Sprintf("<GlobPattern%v>", gp)
 }

eval/list.go

@@ -50,6 +50,10 @@ func (l List) Equal(rhs interface{}) bool {
 	return eqListLike(l, rhs)
 }
 
+func (l List) Hash() uint32 {
+	return hashListLike(l)
+}
+
 func (l List) Repr(indent int) string {
 	var b ListReprBuilder
 	b.Indent = indent

eval/listlike.go

@@ -1,5 +1,7 @@
 package eval
 
+import "github.com/xiaq/persistent/hash"
+
 type ListLike interface {
 	Lener
 	Iterable
@@ -16,3 +18,12 @@ func eqListLike(lhs ListLike, r interface{}) bool {
 	}
 	return true
 }
+
+func hashListLike(l ListLike) uint32 {
+	h := hash.DJBInit
+	l.Iterate(func(v Value) bool {
+		// h = hash.DJBCombine(h, v.Hash())
+		return true
+	})
+	return h
+}

eval/map.go

@@ -30,6 +30,10 @@ func (m Map) Equal(a interface{}) bool {
 	return m == a || eqMapLike(m, a)
 }
 
+func (m Map) Hash() uint32 {
+	return hashMapLike(m)
+}
+
 func (m Map) MarshalJSON() ([]byte, error) {
 	// XXX Not the most efficient way.
 	mm := map[string]Value{}

eval/maplike.go

@@ -1,5 +1,7 @@
 package eval
 
+import "github.com/xiaq/persistent/hash"
+
 type MapLike interface {
 	Lener
 	IndexOneer
@@ -26,3 +28,13 @@ func eqMapLike(lhs MapLike, a interface{}) bool {
 	})
 	return eq
 }
+
+func hashMapLike(m MapLike) uint32 {
+	h := hash.DJBInit
+	m.IteratePair(func(k, v Value) bool {
+		// h = hash.DJBCombine(h, k.Hash())
+		// h = hash.DJBCombine(h, v.Hash())
+		return true
+	})
+	return h
+}

eval/pipe.go

@@ -3,6 +3,8 @@ package eval
 import (
 	"fmt"
 	"os"
+
+	"github.com/xiaq/persistent/hash"
 )
 
 type Pipe struct {
@@ -19,6 +21,13 @@ func (p Pipe) Equal(rhs interface{}) bool {
 	return p == rhs
 }
 
+func (p Pipe) Hash() uint32 {
+	h := hash.DJBInit
+	h = hash.DJBCombine(h, hash.UIntPtr(p.r.Fd()))
+	h = hash.DJBCombine(h, hash.UIntPtr(p.w.Fd()))
+	return h
+}
+
 func (p Pipe) Repr(int) string {
 	return fmt.Sprintf("<pipe{%v %v}>", p.r.Fd(), p.w.Fd())
 }

eval/rat.go

@@ -4,6 +4,8 @@ import (
 	"errors"
 	"fmt"
 	"math/big"
+
+	"github.com/xiaq/persistent/hash"
 )
 
 var ErrOnlyStrOrRat = errors.New("only str or rat may be converted to rat")
@@ -30,6 +32,11 @@ func (r Rat) Equal(a interface{}) bool {
 	return r.b.Cmp(r2.b) == 0
 }
 
+func (r Rat) Hash() uint32 {
+	// TODO(xiaq): Use a more efficient implementation.
+	return hash.String(r.String())
+}
+
 func (r Rat) Repr(int) string {
 	return "(rat " + r.String() + ")"
 }

eval/string.go

@@ -4,6 +4,7 @@ import (
 	"unicode/utf8"
 
 	"github.com/elves/elvish/parse"
+	"github.com/xiaq/persistent/hash"
 )
 
 // String is just a string.
@@ -26,6 +27,10 @@ func (s String) Equal(rhs interface{}) bool {
 	return s == rhs
 }
 
+func (s String) Hash() uint32 {
+	return hash.String(string(s))
+}
+
 func (s String) String() string {
 	return string(s)
 }

eval/struct.go

@@ -31,6 +31,10 @@ func (s *Struct) Equal(rhs interface{}) bool {
 	return s == rhs || eqMapLike(s, rhs)
 }
 
+func (s *Struct) Hash() uint32 {
+	return hashMapLike(s)
+}
+
 func (s *Struct) Repr(indent int) string {
 	var builder MapReprBuilder
 	builder.Indent = indent

eval/value.go

@@ -17,6 +17,7 @@ const (
 type Value interface {
 	Kinder
 	Equaler
+	Hasher
 	Reprer
 }