@@ -2,8 +2,9 @@
 
 import (
 	"bytes"
 	"fmt"
+	"reflect"
 	"strconv"
 )
 
 type stackEntry interface {
@@ -14,14 +15,89 @@
 type lenable interface {
 	Length() int
 }
 
+func runEq(m *machine) error {
+	a := m.popValue()
+	b := m.popValue()
+	m.pushValue(Boolean(eq(a, b)))
+	return nil
+}
+
+// Check if two arrays are
+func arrayRefEq(a, b Array) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	if len(a) == 0 {
+		return true
+	}
+	return &a[0] == &b[0]
+}
+
+func mapRefEq(a, b Dict) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	if len(a) == 0 {
+		return true
+	}
+	aVal := reflect.ValueOf(a).Pointer()
+	bVal := reflect.ValueOf(b).Pointer()
+	return aVal == bVal
+}
+
+func eq(a, b stackEntry) bool {
+
+	if a.Type() != b.Type() {
+		return false
+	}
+	// Otherwise, the types are the same and we can compare them
+	switch a.Type() {
+	case "Boolean":
+		return a.(Boolean) == b.(Boolean)
+	case "String":
+		return a.String() == b.String()
+	case "Integer":
+		return a.(Integer) == b.(Integer)
+	case "Double":
+		return a.(Double) == b.(Double)
+	case "Symbol":
+		return a.(Symbol) == b.(Symbol)
+	case "Vector":
+		return arrayRefEq(a.(Array), b.(Array))
+	case "Dictionary":
+		return mapRefEq(a.(Dict), b.(Dict))
+	case "Quotation":
+		return &a == &b
+	case "Go Word":
+		return &a == &b
+	}
+	// If we got here, something
+	panic("eq failed!!!")
+
+}
+
+// Boolean is the PISC wrapper around bools
 type Boolean bool
+
+// Integer is the PISC wrapper around ints
 type Integer int
+
+// Double is the PISC wrapper aroudn float64
 type Double float64
+
+// Dict is the wrapper around dictionaries.
+// TODO: Find a way to support dicts with arbitrary keys, not just strings
 type Dict map[string]stackEntry
+
+// Array is the wrapper around slices of stackEntry
 type Array []stackEntry
+
+// String is the PISC wrapper around strings
 type String string
+
+// Symbol is used for unique symboles
 type Symbol int64
 
 // This is a separate sematic from arrays.
 type quotation struct {
@@ -39,12 +115,8 @@
 func (g GoFunc) String() string {
 	return "<Native Code>"
 }
 
-func (g GoFunc) Type() string {
-	return "Go Word"
-}
-
 func (s String) String() string {
 	return string(s)
 }
 
@@ -92,8 +164,12 @@
 
 func (a Array) String() string {
 	return fmt.Sprint([]stackEntry(a))
 }
+
+func (g GoFunc) Type() string {
+	return "Go Word"
+}
 
 func (i Integer) Type() string {
 	return "Integer"
 }
@@ -122,9 +198,9 @@
 	return "String"
 }
 
 func (s Symbol) Type() string {
-	return "ERROR: Symbol observed on stack!"
+	return "Symbol"
 }
 
 func (dict Dict) Length() int {
 	return len(dict)