Changed permission codes to only determine private/public/readonly

Changing permissions within the module was redundant and would have just
conflicted with the :mut type qualifier. This is easier to understand.

types/permission.go

@@ -1,48 +1,63 @@
 package types
 
-type Mode int
+type Permission int
 
 const (
-	ModeNone = iota
-	ModeRead
-	ModeWrite
+	// Displays as: pv
+	//
+	// Other modules cannot access the section or member.
+	PermissionPrivate Permission = iota
+
+	// Displays as: ro
+	//
+	// Other modules can access the section or member, but can only read its
+	// value. It is effectively immutable.
+	// 
+	// Data sections, member variables, etc: The value can be read by other
+	// modules but not altered by them
+	//
+	// Functions: The function can be called by other modules.
+	//
+	// Methods: The method can be called by other modules, but cannot be
+	// overriden by a type defined in another module inheriting from this
+	// method's reciever.
+	PermissionReadOnly
+
+	// Displays as: rw
+	//
+	// Other modules cannot only access the section or member's value, but
+	// can alter it. It is effectively mutable. 
+	// 
+	// Data sections, member variables, etc: The value can be read and
+	// altered at will by other modules.
+	//
+	// Functions: This permission cannot be applied to non-method functions.
+	//
+	// Methods: The method can be called by other modules, and overridden by
+	// types defined in other modules inheriting from the method's reciever.
+	PermissionReadWrite
 )
 
-type Permission struct {
-	Internal Mode
-	External Mode
-}
-
-func ModeFrom (char rune) (mode Mode) {
-	switch (char) {
-	case 'n': mode = ModeNone
-	case 'r': mode = ModeRead
-	case 'w': mode = ModeWrite	
+// PermissionFrom creates a new permission value from the specified text. If the
+// input text was not valid, the function returns false for worked. Otherwise,
+// it returns true.
+func PermissionFrom (data string) (permission Permission, worked bool) {
+	worked = true
+	switch data {
+	case "pv": permission = PermissionPrivate
+	case "ro": permission = PermissionReadOnly
+	case "rw": permission = PermissionReadWrite
+	default:   worked = false
 	}
-
-	return
-}
-
-func PermissionFrom (data string) (permission Permission) {
-	if len(data) != 2 { return }
-
-	permission.Internal = ModeFrom(rune(data[0]))
-	permission.External = ModeFrom(rune(data[1]))
-	return
-}
-
-func (mode Mode) ToString () (output string) {
-	switch mode {
-	case ModeNone:  output = "n"
-	case ModeRead:  output = "r"
-	case ModeWrite: output = "w"
-	}
-
 	return
 }
 
+// ToString converts the permission value into a string.
 func (permission Permission) ToString () (output string) {
-	output += permission.Internal.ToString()
-	output += permission.External.ToString()
+	switch permission {
+	case PermissionPrivate:   output = "pv"
+	case PermissionReadOnly:  output = "ro"
+	case PermissionReadWrite: output = "rw"
+	}
 	return
 }