46 строки
775 Б
Go
46 строки
775 Б
Go
package gherkin
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type item struct {
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next, prev *item
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value *Token
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}
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// AST is a linked list to store gherkin Tokens
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// used to insert errors and other details into
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// the token tree
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type AST struct {
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head, tail *item
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}
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func newAST() *AST {
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return &AST{}
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}
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func (l *AST) addTail(t *Token) *item {
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it := &item{next: nil, prev: l.tail, value: t}
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if l.head == nil {
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l.head = it
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} else {
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l.tail.next = it
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}
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l.tail = it
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return l.tail
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}
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func (l *AST) addBefore(t *Token, i *item) *item {
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it := &item{next: i, prev: i.prev, value: t}
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i.prev = it
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if it.prev == nil {
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l.head = it
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}
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return it
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}
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func (l *AST) addAfter(t *Token, i *item) *item {
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it := &item{next: i.next, prev: i, value: t}
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i.next = it
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if it.next == nil {
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l.tail = it
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}
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return it
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}
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