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|
package peg
import(
//"fmt"
)
type (
ExpressionTree struct {
Name string
Children []*ExpressionTree
Value int
}
)
// collapse the expression tree (removing anything that isn't a NonTerminal or
// a Terminal)
func (this *ExpressionTree) collapse() {
ncs := make([]*ExpressionTree, 0)
for _, c := range this.Children {
c.collapse()
if c.Name == "" && c.Value == -1 {
for _, gc := range c.Children {
ncs = append(ncs, gc)
}
} else {
ncs = append(ncs, c)
}
}
this.Children = ncs
}
func (this *ExpressionTree) toString(indent int) string {
str := ""
for i := 0; i < indent; i++ {
str += " "
}
if this.Value > -1 {
str += "<" + string(this.Value) + ">"
} else {
str += this.Name
}
for _, t := range this.Children {
str += "\n" + t.toString(indent + 2)
}
return str
}
func (this *ExpressionTree) String() string {
return this.toString(0)
}
|
