Use prompt_toolkit.token everywhere. (Make pygments more optional.)

prompt_toolkit/contrib/regular_languages/lexer.py

@@ -3,8 +3,8 @@
 the input using a regular grammar with token annotations.
 """
 from __future__ import unicode_literals
-from pygments.token import Token
 from prompt_toolkit.layout.lexers import Lexer
+from prompt_toolkit.token import Token
 
 from .compiler import _CompiledGrammar
 

prompt_toolkit/layout/toolbars.py

@@ -1,12 +1,10 @@
 from __future__ import unicode_literals
 
-from pygments.lexers import BashLexer
-
 from ..enums import IncrementalSearchDirection
 
 from .processors import BeforeInput
 
-from .lexers import PygmentsLexer, SimpleLexer
+from .lexers import SimpleLexer
 from .dimension import LayoutDimension
 from .controls import BufferControl, TokenListControl, UIControl
 from .containers import Window, ConditionalContainer
@@ -38,7 +36,6 @@ def __init__(self, get_tokens, filter=Always(), **kw):
 class SystemToolbarControl(BufferControl):
     def __init__(self):
         super(SystemToolbarControl, self).__init__(
-            lexer=PygmentsLexer(BashLexer),
             buffer_name=SYSTEM_BUFFER,
             input_processors=[BeforeInput.static('Shell command: ', Token.Toolbar.System)],)
 

prompt_toolkit/shortcuts.py

@@ -49,10 +49,14 @@
 from six import text_type, exec_, PY2
 
 import os
-import pygments.lexer
 import sys
 import textwrap
 
+try:
+    from pygments.lexer import Lexer as pygments_Lexer
+except ImportError:
+    pygments_Lexer = None
+
 if is_windows():
     from .terminal.win32_output import Win32Output
     from .terminal.conemu_output import ConEmuOutput
@@ -209,7 +213,7 @@ def create_prompt_layout(message='', lexer=None, is_password=False,
     # class is given, turn it into a PygmentsLexer. (Important for
     # backwards-compatibility.)
     try:
-        if issubclass(lexer, pygments.lexer.Lexer):
+        if pygments_Lexer and issubclass(lexer, pygments.lexer.Lexer):
             lexer = PygmentsLexer(lexer)
     except TypeError: # Happens when lexer is `None` or an instance of something else.
         pass

prompt_toolkit/styles.py

@@ -1,14 +1,23 @@
 """
 Styling for prompt_toolkit applications.
+
+Pygments needs to be installed for usage of ``PygmentsStyle``.
 """
 from __future__ import unicode_literals
 from abc import ABCMeta, abstractmethod
 from collections import namedtuple
-from pygments.token import Token
 from six import with_metaclass
 
-import pygments.style
-import pygments.styles.default
+from .token import Token
+
+# Following imports are only needed when a ``PygmentsStyle`` class is used.
+try:
+    from pygments.style import Style as pygments_Style
+    from pygments.styles.default import DefaultStyle as pygments_DefaultStyle
+except ImportError:
+    pygments_Style = None
+    pygments_DefaultStyle = None
+
 
 __all__ = (
     'Style',
@@ -97,7 +106,7 @@ class PygmentsStyle(Style):
     :param pygments_style_cls: Pygments ``Style`` class.
     """
     def __init__(self, pygments_style_cls):
-        assert issubclass(pygments_style_cls, pygments.style.Style)
+        assert issubclass(pygments_style_cls, pygments_Style)
         self.pygments_style_cls = pygments_style_cls
         self._token_to_attrs_dict = None
 
@@ -120,7 +129,7 @@ def invalidation_hash(self):
 
     @classmethod
     def from_defaults(cls, style_dict=None,
-                      pygments_style_cls=pygments.styles.default.DefaultStyle,
+                      pygments_style_cls=pygments_DefaultStyle,
                       include_extensions=True):
         """
         Shortcut to create a :class:`.PygmentsStyle` instance from a Pygments
@@ -131,9 +140,9 @@ def from_defaults(cls, style_dict=None,
         :param include_extensions: (`bool`) Include prompt_toolkit extensions.
         """
         assert style_dict is None or isinstance(style_dict, dict)
-        assert pygments_style_cls is None or issubclass(pygments_style_cls, pygments.style.Style)
+        assert pygments_style_cls is None or issubclass(pygments_style_cls, pygments_Style)
 
-        class _CustomStyle(pygments.styles.default.DefaultStyle):
+        class _CustomStyle(pygments_DefaultStyle):
             background_color = None
             styles = {}
 

prompt_toolkit/token.py

@@ -30,4 +30,9 @@ def __repr__(self):
         return 'Token' + (self and '.' or '') + '.'.join(self)
 
 
-Token = _TokenType()
+# Prefer the Token class from Pygments. If Pygments is not installed, use our
+# minimalistic Token class.
+try:
+    from pygments.token import Token
+except ImportError:
+    Token = _TokenType()

tools/debug_vt100_input.py

@@ -3,11 +3,11 @@
 Parse vt100 input and print keys.
 For testing terminal input.
 """
-
 from __future__ import unicode_literals
+import sys
+
 from prompt_toolkit.terminal.vt100_input import InputStream, raw_mode
 from prompt_toolkit.keys import Keys
-import sys
 
 
 def callback(key_press):