Move ASTNode merging methods to QL package

pkg/ql/util.go

@@ -18,3 +18,39 @@ func evalBool(v string) bool {
 func isFloaty(v string) bool {
 	return strings.Contains(v, ".")
 }
+
+func MergeAnd(a, b *ASTNode) *ASTNode {
+	return merger(a, b, "and")
+}
+
+func MergeOr(a, b *ASTNode) *ASTNode {
+	return merger(a, b, "or")
+}
+
+func merger(a, b *ASTNode, ref string) *ASTNode {
+	// 1. merge the two
+	aa := make(ASTNodeSet, 0, 2)
+
+	// It needs to be under a group, so we get an `(a) and/or (b)`
+	if a != nil {
+		aa = append(aa, &ASTNode{Ref: "group", Args: ASTNodeSet{a}})
+	}
+	if b != nil {
+		aa = append(aa, &ASTNode{Ref: "group", Args: ASTNodeSet{b}})
+	}
+
+	// 2. flatten
+	// @todo do some more in-depth processing?
+	if len(aa) == 1 {
+		// this [0][0] will always hold if we get to this point
+		return aa[0].Args[0]
+	}
+	if len(aa) == 0 {
+		return nil
+	}
+
+	return &ASTNode{
+		Ref:  ref,
+		Args: aa,
+	}
+}