Improve debugging output

1 files changed, 36 insertions, 0 deletions

diff --git a/result.go b/result.go
new file mode 100644
index 0000000..cdad054
--- /dev/null
+++ b/result.go
@@ -0,0 +1,36 @@
+package goparsify
+
+import (
+	"fmt"
+	"strings"
+)
+
+var TrashResult = &Result{}
+
+// Result is the output of a parser. Usually only one of its fields will be set and should be though of
+// more as a union type. having it avoids interface{} littered all through the parsing code and makes
+// the it easy to do the two most common operations, getting a token and finding a child.
+type Result struct {
+	Token  string
+	Child  []Result
+	Result interface{}
+}
+
+func (r Result) String() string {
+	if r.Result != nil {
+		if rs, ok := r.Result.(fmt.Stringer); ok {
+			return rs.String()
+		}
+		return fmt.Sprintf("%#v", r.Result)
+	}
+
+	if len(r.Child) > 0 {
+		children := []string{}
+		for _, child := range r.Child {
+			children = append(children, child.String())
+		}
+		return "[" + strings.Join(children, ",") + "]"
+	}
+
+	return r.Token
+}