added

vendor/github.com/glycerine/zygomys/zygo/comment.go

@@ -0,0 +1,105 @@
+package zygo
+
+type SexpComment struct {
+	Comment string
+	Block   bool
+}
+
+func (p *SexpComment) SexpString(ps *PrintState) string {
+	return p.Comment
+}
+
+func (p *SexpComment) Type() *RegisteredType {
+	return GoStructRegistry.Registry["comment"]
+}
+
+// Filters return true to keep, false to drop.
+type Filter func(x Sexp) bool
+
+func RemoveCommentsFilter(x Sexp) bool {
+	switch x.(type) {
+	case *SexpComment:
+		//P("RemoveCommentsFilter called on x= %T/val=%v. return false", x, x)
+		return false
+	default:
+		//P("RemoveCommentsFilter called on x= %T/val=%v. return true", x, x)
+		return true
+	}
+}
+
+// detect SexpEnd values and return false on them to filter them out.
+func RemoveEndsFilter(x Sexp) bool {
+	switch n := x.(type) {
+	case *SexpSentinel:
+		if n.Val == SexpEnd.Val {
+			return false
+		}
+	}
+	return true
+}
+
+// detect SexpComma values and return false on them to filter them out.
+func RemoveCommasFilter(x Sexp) bool {
+	switch x.(type) {
+	case *SexpComma:
+		return false
+	}
+	return true
+}
+
+func (env *Zlisp) FilterAny(x Sexp, f Filter) (filtered Sexp, keep bool) {
+	switch ele := x.(type) {
+	case *SexpArray:
+		res := &SexpArray{Val: env.FilterArray(ele.Val, f), Typ: ele.Typ, IsFuncDeclTypeArray: ele.IsFuncDeclTypeArray, Env: env}
+		return res, true
+	case *SexpPair:
+		return env.FilterList(ele, f), true
+	case *SexpHash:
+		return env.FilterHash(ele, f), true
+	default:
+		keep = f(x)
+		if keep {
+			return x, true
+		}
+		return SexpNull, false
+	}
+}
+
+func (env *Zlisp) FilterArray(x []Sexp, f Filter) []Sexp {
+	//P("FilterArray: before: %d in size", len(x))
+	//for i := range x {
+	//P("x[i=%d] = %v", i, x[i].SexpString())
+	//}
+	res := []Sexp{}
+	for i := range x {
+		filtered, keep := env.FilterAny(x[i], f)
+		if keep {
+			res = append(res, filtered)
+		}
+	}
+	//P("FilterArray: after: %d in size", len(res))
+	//for i := range res {
+	//P("x[i=%d] = %v", i, res[i].SexpString())
+	//}
+	return res
+}
+
+func (env *Zlisp) FilterHash(h *SexpHash, f Filter) *SexpHash {
+	// should not actually need this, since hashes
+	// don't yet exist in parsed symbols. (they are
+	// still lists).
+	//P("in FilterHash")
+	return h
+}
+
+func (env *Zlisp) FilterList(h *SexpPair, f Filter) Sexp {
+	//P("in FilterList")
+	arr, err := ListToArray(h)
+	res := []Sexp{}
+	if err == NotAList {
+		// don't filter pair lists
+		return h
+	}
+	res = env.FilterArray(arr, f)
+	return MakeList(res)
+}