Thomas Pelletier
59 lines
909 B
Go
59 lines
909 B
Go
package ast
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type Builder struct {
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nodes []Node
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lastIdx int
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}
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type Reference struct {
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idx int
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set bool
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}
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func (r Reference) Valid() bool {
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return r.set
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}
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func (b *Builder) Finish() *Root {
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r := &Root{
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nodes: b.nodes,
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}
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b.nodes = nil
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for i := range r.nodes {
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r.nodes[i].root = r
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}
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return r
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}
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func (b *Builder) Push(n Node) Reference {
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b.lastIdx = len(b.nodes)
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b.nodes = append(b.nodes, n)
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return Reference{
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idx: b.lastIdx,
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set: true,
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}
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}
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func (b *Builder) PushAndChain(n Node) Reference {
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newIdx := len(b.nodes)
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b.nodes = append(b.nodes, n)
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if b.lastIdx >= 0 {
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b.nodes[b.lastIdx].next = newIdx
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}
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b.lastIdx = newIdx
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return Reference{
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idx: b.lastIdx,
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set: true,
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}
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}
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func (b *Builder) AttachChild(parent Reference, child Reference) {
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b.nodes[parent.idx].child = child.idx
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}
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func (b *Builder) Chain(from Reference, to Reference) {
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b.nodes[from.idx].next = to.idx
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}
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