87 lines
1.6 KiB
Go
87 lines
1.6 KiB
Go
// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// iter-list.go
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package expr
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import (
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"fmt"
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"io"
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)
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type ListIterator struct {
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a *ListType
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index int
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}
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func NewListIterator(list *ListType) *ListIterator {
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return &ListIterator{a: list, index: 0}
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}
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func NewArrayIterator(array []any) *ListIterator {
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return &ListIterator{a: (*ListType)(&array), index: 0}
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}
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func NewAnyIterator(value any) (it *ListIterator) {
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if value == nil {
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it = NewArrayIterator([]any{})
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} else if list, ok := value.(*ListType); ok {
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it = NewListIterator(list)
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} else if array, ok := value.([]any); ok {
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it = NewArrayIterator(array)
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} else if it1, ok := value.(*ListIterator); ok {
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it = it1
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} else {
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it = NewArrayIterator([]any{value})
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}
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return
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}
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func (it *ListIterator) String() string {
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var l = 0
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if it.a != nil {
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l = len(*it.a)
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}
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return fmt.Sprintf("$(#%d)", l)
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}
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func (it *ListIterator) HasOperation(name string) bool {
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yes := name == resetName
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return yes
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}
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func (it *ListIterator) CallOperation(name string, args []any) (v any, err error) {
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if name == resetName {
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v, err = it.Reset()
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} else {
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err = errNoOperation(name)
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}
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return
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}
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func (it *ListIterator) Current() (item any, err error) {
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a := *(it.a)
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if it.index >= 0 && it.index < len(a) {
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item = a[it.index]
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} else {
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err = io.EOF
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}
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return
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}
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func (it *ListIterator) Next() (item any, err error) {
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if item, err = it.Current(); err != io.EOF {
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it.index++
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}
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return
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}
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func (it *ListIterator) Index() int {
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return it.index - 1
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}
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func (it *ListIterator) Reset() (bool, error) {
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it.index = 0
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return true, nil
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}
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