goruby/goruby

package ast

import (
    "reflect"
)

// Equal returns true if the nodes are identical in content, false otherwise
func Equal(a, b Node) bool {
    if a == b {
        return true
    }
    if reflect.DeepEqual(a, b) {
        return true
    }

    if reflect.TypeOf(a) != reflect.TypeOf(b) {
        return false
    }

    if _, ok := a.(literal); ok {
        return a.String() == b.String()
    }
    return compareTrees(a, b)
}

func compareTrees(a, b Node) bool {
    res := make(chan bool)

    go func() {
        defer close(res)
        ch1 := WalkEmit(a)
        ch2 := WalkEmit(b)
        for {
            x, ok1 := <-ch1
            y, ok2 := <-ch2
            if !ok1 && !ok2 {
                break
            }
            if !compare(x, y) {
                res <- false
                return
            }
        }
        res <- true
    }()

    return <-res
}

func compare(nodes ...Node) bool {
    if len(nodes) < 2 {
        return false
    }
    var prev, next Node
    for _, n := range nodes {
        if prev == nil {
            prev = n
            continue
        }
        if next != nil {
            prev = next
        }
        next = n
        if reflect.TypeOf(prev) != reflect.TypeOf(next) {
            return false
        }
        if prev.String() != next.String() {
            return false
        }
    }
    return true
}