elvish/eval/map.go
2017-09-16 17:48:53 +01:00

132 lines
2.6 KiB
Go

package eval
import (
"encoding/json"
"errors"
"strings"
"github.com/xiaq/persistent/hashmap"
)
// Map is a map from string to Value.
type Map struct {
inner hashmap.HashMap
}
type HasKeyer interface {
HasKey(k Value) bool
}
var _ MapLike = Map{}
// NewMap creates a new Map from an inner HashMap.
func NewMap(inner hashmap.HashMap) Map {
return Map{inner}
}
// ConvertToMap converts a native Go map to Map.
func ConvertToMap(m map[Value]Value) Map {
inner := hashmap.Empty
for k, v := range m {
inner = inner.Assoc(k, v)
}
return NewMap(inner)
}
func (Map) Kind() string {
return "map"
}
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) {
// TODO(xiaq): Replace with a more efficient implementation.
mm := map[string]Value{}
for it := m.inner.Iterator(); it.HasElem(); it.Next() {
k, v := it.Elem()
mm[ToString(k.(Value))] = v.(Value)
}
return json.Marshal(mm)
}
func (m Map) Repr(indent int) string {
var builder MapReprBuilder
builder.Indent = indent
for it := m.inner.Iterator(); it.HasElem(); it.Next() {
k, v := it.Elem()
builder.WritePair(k.(Value).Repr(indent+1), indent+2, v.(Value).Repr(indent+2))
}
return builder.String()
}
func (m Map) Len() int {
return m.inner.Len()
}
func (m Map) IndexOne(idx Value) Value {
v, ok := m.inner.Get(idx)
if !ok {
throw(errors.New("no such key: " + idx.Repr(NoPretty)))
}
return v.(Value)
}
func (m Map) Assoc(k, v Value) Value {
return Map{m.inner.Assoc(k, v)}
}
func (m Map) Dissoc(k Value) Value {
return Map{m.inner.Without(k)}
}
func (m Map) IterateKey(f func(Value) bool) {
for it := m.inner.Iterator(); it.HasElem(); it.Next() {
k, _ := it.Elem()
if !f(k.(Value)) {
break
}
}
}
func (m Map) IteratePair(f func(Value, Value) bool) {
for it := m.inner.Iterator(); it.HasElem(); it.Next() {
k, v := it.Elem()
if !f(k.(Value), v.(Value)) {
break
}
}
}
func (m Map) HasKey(k Value) bool {
_, ok := m.inner.Get(k)
return ok
}
// MapReprBuilder helps building the Repr of a Map. It is also useful for
// implementing other Map-like values. The zero value of a MapReprBuilder is
// ready to use.
type MapReprBuilder struct {
ListReprBuilder
}
func (b *MapReprBuilder) WritePair(k string, indent int, v string) {
if indent > 0 {
b.WriteElem("&" + k + "=\n" + strings.Repeat(" ", indent) + v)
} else {
b.WriteElem("&" + k + "=" + v)
}
}
func (b *MapReprBuilder) String() string {
if b.buf.Len() == 0 {
return "[&]"
}
return b.ListReprBuilder.String()
}