Add Key object and related functions

1 files changed, 108 insertions, 0 deletions

diff --git a/key.py b/key.py
index e69de29..dc960c1 100644
--- a/key.py
+++ b/key.py
@@ -0,0 +1,108 @@
+ESC = '\x1b'
+
+def assert_type(thing,_type):
+    ''' if thing is not of type _type raise an exception '''
+    if type(thing) is not _type:
+        raise TypeError,
+            "%s is of %s, should be of %s" %
+                (str(thing),type(thing),_type)
+
+class Key:
+    ''' a keyboard keypress object '''
+
+    def __init__(self,name,*modifiers):
+        assert_type(name,str)
+        for m in modifiers:
+            assert isinstance(m,Key),
+                "Modifiers expected to be instances of Key"
+        self.name = name
+        self.modifiers = list(modifiers)
+        self.modifiers.sort()
+
+    def __eq__(self,other):
+        if not isinstance(Key,other): return False
+        return str(self) == str(other)
+
+    def __ne__(self,other):
+        if isinstance(Key,other): return True
+        return str(self) != str(other)
+
+    def __str__(self):
+        to_return = str()
+        for m in self.modifiers:
+            to_return += '%s ' % str(m)
+        to_return += self.name
+        return to_return
+
+    def has_modifier(self,modifier):
+        ''' does this object have the modifier? '''
+        if modifier in self.modifiers:
+            return True
+        return False
+
+    def modify(self,modifier):
+        ''' add a modifier '''
+        if modifier not in self.modifiers:
+            self.modifiers.append(modifier)
+        self.modifiers.sort()
+        return self
+
+ALT = Key('Alt')
+CTRL = Key('Control')
+
+table = {
+        ESC : Key('Escape'),
+        '\t': Key('Tab'),
+        ' ': Key('Space'),
+        '\n': Key('Enter'),
+        '\x7f' : Key('Backspace'),
+        '%sOF' % ESC: Key('End'),
+        '%sOH' % ESC: Key('Home'),
+        '%s[3~' % ESC: Key('Del'),
+        '%s[2~' % ESC: Key('Insert'),
+        '%s[5~' % ESC: Key('PageUp'),
+        '%s[6~' % ESC: Key('PageDown'),
+        '%sOP' % ESC: Key('F1'),
+        '%sOQ' % ESC: Key('F2'),
+        '%sOR' % ESC: Key('F3'),
+        '%sOS' % ESC: Key('F4'),
+        '%s[15~' % ESC: Key('F5'),
+        '%s[17~' % ESC: Key('F6'),
+        '%s[18~' % ESC: Key('F7'),
+        '%s[19~' % ESC: Key('F8'),
+        '%s[20~' % ESC: Key('F9'),
+        '%s[21~' % ESC: Key('F10'),
+        '%s[23~' % ESC: Key('F11'),
+        '%s[24~' % ESC: Key('F12'),
+        '%s[A' % ESC: Key('Up'),
+        '%s[B' % ESC: Key('Down'),
+        '%s[D' % ESC: Key('Left'),
+        '%s[C' % ESC: Key('Right'),
+    }
+
+def is_alt(code):
+    ''' is this the code of a combination modified by Alt? '''
+    assert_type(name,str)
+    if len(code) == 2 and code[0] == ESC:
+        return True
+    return False
+
+def is_ctrl_alpha(code):
+    ''' is this the code of a combination modified by Ctrl? '''
+    assert_type(name,str)
+    if code < '\x20': return True
+    return False
+
+def get_ctrl_alpha(code):
+    ''' get alphabetic key modified by Ctrl '''
+    assert_type(name,str)
+    letter = chr(ord(code) + 0x40)
+    return Key(letter,CTRL)
+
+def parse_code(code):
+    ''' get Key object from code '''
+    assert_type(name,str)
+    if code in table.keys(): return table[code]
+    elif is_alt(code): return from_keycode(code[1:]).modify(ALT)
+    elif is_ctrl_alpha(code): return get_ctrl_alpha(code)
+    else: return Key(code)