124 lines
1.7 KiB
Go
124 lines
1.7 KiB
Go
package list
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import (
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"fmt"
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"strings"
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)
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type IList interface {
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Conj(data any) IList
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First() any
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Rest() IList
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String() string
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IsEmpty() bool
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}
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type EmptyList struct{}
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type List struct {
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Value any
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next IList
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}
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func Empty() IList {
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return new(EmptyList)
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}
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var emptyList = Empty()
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func New(val any) *List {
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this := new(List)
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this.Value = val
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this.next = emptyList
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return this
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}
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func (this *List) Conj(val any) IList {
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new_head := New(val)
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new_head.next = this
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return new_head
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}
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func (this *EmptyList) Conj(val any) IList {
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return Conj(nil, val)
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}
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func Conj(this IList, val any) IList {
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if this == nil {
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return New(val)
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} else {
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return this.Conj(val)
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}
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}
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func Rest(this IList) IList {
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if this == nil {
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return emptyList
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}
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return this.Rest()
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}
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func (this *List) Rest() IList {
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if this == nil {
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return emptyList
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}
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return this.next
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}
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func (this *EmptyList) Rest() IList {
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return emptyList
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}
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func First(this *List) any {
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if this == nil {
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return nil
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}
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return this.Value
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}
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func (this *List) First() any {
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return First(this)
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}
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func (this *EmptyList) First() any {
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return nil
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}
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func IsEmpty(this IList) bool {
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return this == nil || this.IsEmpty()
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}
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func (this *List) IsEmpty() bool {
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return false
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}
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func (this *EmptyList) IsEmpty() bool {
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return true
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}
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func String(this *List) string {
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if IsEmpty(this) {
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return "()"
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}
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var sb strings.Builder
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sb.WriteRune('(')
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// Iterate and print elements
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var e IList
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for e = this; !IsEmpty(e); e = Rest(e) {
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sb.WriteString(fmt.Sprint(e.First()))
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sb.WriteRune(' ')
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}
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return sb.String()[:sb.Len()-1] + ")"
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}
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func (this *List) String() string {
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return String(this)
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}
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func (this *EmptyList) String() string {
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return "()"
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}
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