1 files changed, 95 insertions, 0 deletions
diff --git a/walk/atom.go b/walk/atom.go
new file mode 100644
index 0000000..13ad2ff
--- /dev/null
+++ b/walk/atom.go
@@ -0,0 +1,95 @@
+package walk
+
+import (
+	"math"
+	"fmt"
+)
+
+type AtomType int64
+const (
+	AtomNull AtomType = iota
+	AtomBool
+	AtomNumber
+	AtomTerminal
+	AtomStringTerminal
+	AtomStringRune
+)
+type Atom struct {
+	Typ AtomType
+	data uint64
+}
+func NewAtomNull() Atom {
+	return Atom {
+		Typ: AtomNull,
+		data: 0,
+	}
+}
+func NewAtomBool(v bool) Atom {
+	if v {
+		return Atom {
+			Typ: AtomBool,
+			data: 1,
+		}
+	} else {
+		return Atom {
+			Typ: AtomBool,
+			data: 0,
+		}
+	}
+}
+func NewAtomNumber(v float64) Atom {
+	return Atom {
+		Typ: AtomNumber,
+		data: math.Float64bits(v),
+	}
+}
+func NewAtomTerminal(v ValueTerminal) Atom {
+	return Atom {
+		Typ: AtomTerminal,
+		data: uint64(v),
+	}
+}
+func NewAtomStringTerminal() Atom {
+	return Atom {
+		Typ: AtomStringTerminal,
+		data: 0,
+	}
+}
+func NewAtomStringRune(v rune) Atom {
+	return Atom {
+		Typ: AtomStringRune,
+		data: uint64(v),
+	}
+}
+func (v Atom) String() string {
+	switch v.Typ {
+		case AtomNull:
+			return "null"
+		case AtomBool:
+			if v.data == 0 {
+				return "false"
+			}
+			return "true"
+		case AtomNumber:
+			return fmt.Sprintf("%v", math.Float64frombits(v.data))
+		case AtomTerminal:
+			switch ValueTerminal(v.data) {
+				case MapBegin:
+					return "{"
+				case MapEnd:
+					return "}"
+				case ArrayBegin:
+					return "["
+				case ArrayEnd:
+					return "]"
+				default:
+					panic("Invalid terminal atom")
+			}
+		case AtomStringTerminal:
+			return "\""
+		case AtomStringRune:
+			return string(rune(v.data))
+		default:
+			panic("Invalid atom type")
+	}
+}