Changed allow_ansi to allow_style for accuracy in what types of ANSI escape sequences are handled

Author: kmvanbrunt

README.md

@@ -317,7 +317,7 @@ example/transcript_regex.txt:
 # The regex for editor will match whatever program you use.
 # regexes on prompts just make the trailing space obvious
 (Cmd) set
-allow_ansi: Terminal
+allow_style: Terminal
 continuation_prompt: >/ /
 debug: False
 echo: False

cmd2/ansi.py

@@ -1,5 +1,8 @@
 # coding=utf-8
-"""Support for ANSI escape sequences which are used for things like applying style to text"""
+"""
+Support for ANSI escape sequences which are used for things like applying style to text,
+setting the window title, and asynchronous alerts.
+ """
 import functools
 import re
 from typing import Any, IO
@@ -11,16 +14,17 @@
 # On Windows, filter ANSI escape codes out of text sent to stdout/stderr, and replace them with equivalent Win32 calls
 colorama.init(strip=False)
 
-# Values for allow_ansi setting
-ANSI_NEVER = 'Never'
-ANSI_TERMINAL = 'Terminal'
-ANSI_ALWAYS = 'Always'
+# Values for allow_style setting
+STYLE_NEVER = 'Never'
+STYLE_TERMINAL = 'Terminal'
+STYLE_ALWAYS = 'Always'
 
-# Controls when ANSI escape sequences are allowed in output
-allow_ansi = ANSI_TERMINAL
+# Controls when ANSI style style sequences are allowed in output
+allow_style = STYLE_TERMINAL
 
-# Regular expression to match ANSI escape sequences
-ANSI_ESCAPE_RE = re.compile(r'\x1b[^m]*m')
+# Regular expression to match ANSI style sequences
+# This matches: colorama.ansi.CSI + digit(s) + m
+ANSI_STYLE_RE = re.compile(r'\033\[[0-9]+m')
 
 # Foreground color presets
 FG_COLORS = {
@@ -71,41 +75,41 @@
 BRIGHT = Style.BRIGHT
 NORMAL = Style.NORMAL
 
-# ANSI escape sequences not provided by colorama
+# ANSI style sequences not provided by colorama
 UNDERLINE_ENABLE = colorama.ansi.code_to_chars(4)
 UNDERLINE_DISABLE = colorama.ansi.code_to_chars(24)
 
 
-def strip_ansi(text: str) -> str:
+def strip_style(text: str) -> str:
     """
-    Strip ANSI escape sequences from a string.
+    Strip ANSI style sequences from a string.
 
-    :param text: string which may contain ANSI escape sequences
-    :return: the same string with any ANSI escape sequences removed
+    :param text: string which may contain ANSI style sequences
+    :return: the same string with any ANSI style sequences removed
     """
-    return ANSI_ESCAPE_RE.sub('', text)
+    return ANSI_STYLE_RE.sub('', text)
 
 
 def ansi_safe_wcswidth(text: str) -> int:
     """
-    Wrap wcswidth to make it compatible with strings that contains ANSI escape sequences
+    Wrap wcswidth to make it compatible with strings that contains ANSI style sequences
 
     :param text: the string being measured
     """
-    # Strip ANSI escape sequences since they cause wcswidth to return -1
-    return wcswidth(strip_ansi(text))
+    # Strip ANSI style sequences since they cause wcswidth to return -1
+    return wcswidth(strip_style(text))
 
 
 def ansi_aware_write(fileobj: IO, msg: str) -> None:
     """
-    Write a string to a fileobject and strip its ANSI escape sequences if required by allow_ansi setting
+    Write a string to a fileobject and strip its ANSI style sequences if required by allow_style setting
 
     :param fileobj: the file object being written to
     :param msg: the string being written
     """
-    if allow_ansi.lower() == ANSI_NEVER.lower() or \
-            (allow_ansi.lower() == ANSI_TERMINAL.lower() and not fileobj.isatty()):
-        msg = strip_ansi(msg)
+    if allow_style.lower() == STYLE_NEVER.lower() or \
+            (allow_style.lower() == STYLE_TERMINAL.lower() and not fileobj.isatty()):
+        msg = strip_style(msg)
     fileobj.write(msg)
 
 
@@ -176,7 +180,7 @@ def style(text: Any, *, fg: str = '', bg: str = '', bold: bool = False, underlin
         additions.append(UNDERLINE_ENABLE)
         removals.append(UNDERLINE_DISABLE)
 
-    # Combine the ANSI escape sequences with the text
+    # Combine the ANSI style sequences with the text
     return "".join(additions) + text + "".join(removals)
 
 

cmd2/cmd2.py

@@ -206,11 +206,11 @@ def __init__(self, completekey: str = 'tab', stdin=None, stdout=None, *,
         # To make an attribute settable with the "do_set" command, add it to this ...
         self.settable = \
             {
-                # allow_ansi is a special case in which it's an application-wide setting defined in ansi.py
-                'allow_ansi': ('Allow ANSI escape sequences in output '
-                               '(valid values: {}, {}, {})'.format(ansi.ANSI_TERMINAL,
-                                                                   ansi.ANSI_ALWAYS,
-                                                                   ansi.ANSI_NEVER)),
+                # allow_style is a special case in which it's an application-wide setting defined in ansi.py
+                'allow_style': ('Allow ANSI style sequences in output '
+                                '(valid values: {}, {}, {})'.format(ansi.STYLE_TERMINAL,
+                                                                    ansi.STYLE_ALWAYS,
+                                                                    ansi.STYLE_NEVER)),
                 'continuation_prompt': 'On 2nd+ line of input',
                 'debug': 'Show full error stack on error',
                 'echo': 'Echo command issued into output',
@@ -366,7 +366,7 @@ def __init__(self, completekey: str = 'tab', stdin=None, stdout=None, *,
         else:
             # Here is the meaning of the various flags we are using with the less command:
             # -S causes lines longer than the screen width to be chopped (truncated) rather than wrapped
-            # -R causes ANSI "color" escape sequences to be output in raw form (i.e. colors are displayed)
+            # -R causes ANSI "style" escape sequences to be output in raw form (i.e. colors are displayed)
             # -X disables sending the termcap initialization and deinitialization strings to the terminal
             # -F causes less to automatically exit if the entire file can be displayed on the first screen
             self.pager = 'less -RXF'
@@ -395,38 +395,38 @@ def __init__(self, completekey: str = 'tab', stdin=None, stdout=None, *,
     # -----  Methods related to presenting output to the user -----
 
     @property
-    def allow_ansi(self) -> str:
-        """Read-only property needed to support do_set when it reads allow_ansi"""
-        return ansi.allow_ansi
+    def allow_style(self) -> str:
+        """Read-only property needed to support do_set when it reads allow_style"""
+        return ansi.allow_style
 
-    @allow_ansi.setter
-    def allow_ansi(self, new_val: str) -> None:
-        """Setter property needed to support do_set when it updates allow_ansi"""
+    @allow_style.setter
+    def allow_style(self, new_val: str) -> None:
+        """Setter property needed to support do_set when it updates allow_style"""
         new_val = new_val.lower()
-        if new_val == ansi.ANSI_TERMINAL.lower():
-            ansi.allow_ansi = ansi.ANSI_TERMINAL
-        elif new_val == ansi.ANSI_ALWAYS.lower():
-            ansi.allow_ansi = ansi.ANSI_ALWAYS
-        elif new_val == ansi.ANSI_NEVER.lower():
-            ansi.allow_ansi = ansi.ANSI_NEVER
+        if new_val == ansi.STYLE_TERMINAL.lower():
+            ansi.allow_style = ansi.STYLE_TERMINAL
+        elif new_val == ansi.STYLE_ALWAYS.lower():
+            ansi.allow_style = ansi.STYLE_ALWAYS
+        elif new_val == ansi.STYLE_NEVER.lower():
+            ansi.allow_style = ansi.STYLE_NEVER
         else:
-            self.perror('Invalid value: {} (valid values: {}, {}, {})'.format(new_val, ansi.ANSI_TERMINAL,
-                                                                              ansi.ANSI_ALWAYS, ansi.ANSI_NEVER))
+            self.perror('Invalid value: {} (valid values: {}, {}, {})'.format(new_val, ansi.STYLE_TERMINAL,
+                                                                              ansi.STYLE_ALWAYS, ansi.STYLE_NEVER))
 
     def _completion_supported(self) -> bool:
         """Return whether tab completion is supported"""
         return self.use_rawinput and self.completekey and rl_type != RlType.NONE
 
     @property
     def visible_prompt(self) -> str:
-        """Read-only property to get the visible prompt with any ANSI escape codes stripped.
+        """Read-only property to get the visible prompt with any ANSI style escape codes stripped.
 
         Used by transcript testing to make it easier and more reliable when users are doing things like coloring the
         prompt using ANSI color codes.
 
         :return: prompt stripped of any ANSI escape codes
         """
-        return ansi.strip_ansi(self.prompt)
+        return ansi.strip_style(self.prompt)
 
     def poutput(self, msg: Any = '', *, end: str = '\n') -> None:
         """Print message to self.stdout and appends a newline by default
@@ -551,8 +551,8 @@ def ppaged(self, msg: Any, *, end: str = '\n', chop: bool = False) -> None:
             # Don't attempt to use a pager that can block if redirecting or running a script (either text or Python)
             # Also only attempt to use a pager if actually running in a real fully functional terminal
             if functional_terminal and not self._redirecting and not self.in_pyscript() and not self.in_script():
-                if ansi.allow_ansi.lower() == ansi.ANSI_NEVER.lower():
-                    msg_str = ansi.strip_ansi(msg_str)
+                if ansi.allow_style.lower() == ansi.STYLE_NEVER.lower():
+                    msg_str = ansi.strip_style(msg_str)
                 msg_str += end
 
                 pager = self.pager

cmd2/transcript.py

@@ -56,13 +56,13 @@ def _fetchTranscripts(self):
     def _test_transcript(self, fname: str, transcript):
         line_num = 0
         finished = False
-        line = ansi.strip_ansi(next(transcript))
+        line = ansi.strip_style(next(transcript))
         line_num += 1
         while not finished:
             # Scroll forward to where actual commands begin
             while not line.startswith(self.cmdapp.visible_prompt):
                 try:
-                    line = ansi.strip_ansi(next(transcript))
+                    line = ansi.strip_style(next(transcript))
                 except StopIteration:
                     finished = True
                     break
@@ -89,15 +89,15 @@ def _test_transcript(self, fname: str, transcript):
             result = self.cmdapp.stdout.read()
             stop_msg = 'Command indicated application should quit, but more commands in transcript'
             # Read the expected result from transcript
-            if ansi.strip_ansi(line).startswith(self.cmdapp.visible_prompt):
+            if ansi.strip_style(line).startswith(self.cmdapp.visible_prompt):
                 message = '\nFile {}, line {}\nCommand was:\n{}\nExpected: (nothing)\nGot:\n{}\n'.format(
                           fname, line_num, command, result)
                 self.assertTrue(not (result.strip()), message)
                 # If the command signaled the application to quit there should be no more commands
                 self.assertFalse(stop, stop_msg)
                 continue
             expected = []
-            while not ansi.strip_ansi(line).startswith(self.cmdapp.visible_prompt):
+            while not ansi.strip_style(line).startswith(self.cmdapp.visible_prompt):
                 expected.append(line)
                 try:
                     line = next(transcript)

cmd2/utils.py

@@ -641,7 +641,7 @@ def align_text(text: str, alignment: TextAlignment, *, fill_char: str = ' ',
                width: Optional[int] = None, tab_width: int = 4) -> str:
     """
     Align text for display within a given width. Supports characters with display widths greater than 1.
-    ANSI escape sequences are safely ignored and do not count toward the display width. This means colored text is
+    ANSI style sequences are safely ignored and do not count toward the display width. This means colored text is
     supported. If text has line breaks, then each line is aligned independently.
 
     There are convenience wrappers around this function: align_left(), align_center(), and align_right()
@@ -688,7 +688,7 @@ def align_text(text: str, alignment: TextAlignment, *, fill_char: str = ' ',
             text_buf.write('\n')
 
         # Use ansi_safe_wcswidth to support characters with display widths
-        # greater than 1 as well as ANSI escape sequences
+        # greater than 1 as well as ANSI style sequences
         line_width = ansi.ansi_safe_wcswidth(line)
         if line_width == -1:
             raise(ValueError("Text to align contains an unprintable character"))
@@ -728,7 +728,7 @@ def align_text(text: str, alignment: TextAlignment, *, fill_char: str = ' ',
 def align_left(text: str, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4) -> str:
     """
     Left align text for display within a given width. Supports characters with display widths greater than 1.
-    ANSI escape sequences are safely ignored and do not count toward the display width. This means colored text is
+    ANSI style sequences are safely ignored and do not count toward the display width. This means colored text is
     supported. If text has line breaks, then each line is aligned independently.
 
     :param text: text to left align (can contain multiple lines)
@@ -746,7 +746,7 @@ def align_left(text: str, *, fill_char: str = ' ', width: Optional[int] = None,
 def align_center(text: str, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4) -> str:
     """
     Center text for display within a given width. Supports characters with display widths greater than 1.
-    ANSI escape sequences are safely ignored and do not count toward the display width. This means colored text is
+    ANSI style sequences are safely ignored and do not count toward the display width. This means colored text is
     supported. If text has line breaks, then each line is aligned independently.
 
     :param text: text to center (can contain multiple lines)
@@ -764,7 +764,7 @@ def align_center(text: str, *, fill_char: str = ' ', width: Optional[int] = None
 def align_right(text: str, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4) -> str:
     """
     Right align text for display within a given width. Supports characters with display widths greater than 1.
-    ANSI escape sequences are safely ignored and do not count toward the display width. This means colored text is
+    ANSI style sequences are safely ignored and do not count toward the display width. This means colored text is
     supported. If text has line breaks, then each line is aligned independently.
 
     :param text: text to right align (can contain multiple lines)

docs/features/generating_output.rst

@@ -45,23 +45,23 @@ changing the value of the ``quiet`` setting.
 Colored Output
 --------------
 
-The output methods in the previous section all honor the ``allow_ansi``
+The output methods in the previous section all honor the ``allow_style``
 setting, which has three possible values:
 
 Never
-    poutput(), pfeedback(), and ppaged() strip all ANSI escape sequences
+    poutput(), pfeedback(), and ppaged() strip all ANSI style sequences
     which instruct the terminal to colorize output
 
 Terminal
     (the default value) poutput(), pfeedback(), and ppaged() do not strip any
-    ANSI escape sequences when the output is a terminal, but if the output is a
-    pipe or a file the escape sequences are stripped. If you want colorized
-    output you must add ANSI escape sequences using either cmd2's internal ansi
+    ANSI style sequences when the output is a terminal, but if the output is a
+    pipe or a file the style sequences are stripped. If you want colorized
+    output you must add ANSI style sequences using either cmd2's internal ansi
     module or another color library such as `plumbum.colors`, `colorama`, or
     `colored`.
 
 Always
-    poutput(), pfeedback(), and ppaged() never strip ANSI escape sequences,
+    poutput(), pfeedback(), and ppaged() never strip ANSI style sequences,
     regardless of the output destination
 
 Colored and otherwise styled output can be generated using the `ansi.style()`

docs/features/settings.rst

@@ -46,7 +46,7 @@ comments, is viewable from within a running application
 with::
 
     (Cmd) set --long
-    allow_ansi: Terminal           # Allow ANSI escape sequences in output (valid values: Terminal, Always, Never)
+    allow_style: Terminal          # Allow ANSI style sequences in output (valid values: Terminal, Always, Never)
     continuation_prompt: >         # On 2nd+ line of input
     debug: False                   # Show full error stack on error
     echo: False                    # Echo command issued into output
@@ -61,7 +61,7 @@ with::
 Any of these user-settable parameters can be set while running your app with
 the ``set`` command like so::
 
-    set allow_ansi Never
+    set allow_style Never
 
 
 

examples/colors.py

@@ -6,21 +6,21 @@
 Experiment with the command line options on the `speak` command to see how
 different output colors ca
 
-The allow_ansi setting has three possible values:
+The allow_style setting has three possible values:
 
 Never
-    poutput(), pfeedback(), and ppaged() strip all ANSI escape sequences
+    poutput(), pfeedback(), and ppaged() strip all ANSI style sequences
     which instruct the terminal to colorize output
 
 Terminal
     (the default value) poutput(), pfeedback(), and ppaged() do not strip any
-    ANSI escape sequences when the output is a terminal, but if the output is
-    a pipe or a file the escape sequences are stripped. If you want colorized
-    output you must add ANSI escape sequences using either cmd2's internal ansi
+    ANSI style sequences when the output is a terminal, but if the output is
+    a pipe or a file the style sequences are stripped. If you want colorized
+    output you must add ANSI style sequences using either cmd2's internal ansi
     module or another color library such as `plumbum.colors` or `colorama`.
 
 Always
-    poutput(), pfeedback(), and ppaged() never strip ANSI escape sequences,
+    poutput(), pfeedback(), and ppaged() never strip ANSI style sequences,
     regardless of the output destination
 """
 import argparse
@@ -40,7 +40,7 @@ def __init__(self):
         self.settable['maxrepeats'] = 'max repetitions for speak command'
 
         # Should ANSI color output be allowed
-        self.allow_ansi = ansi.ANSI_TERMINAL
+        self.allow_style = ansi.STYLE_TERMINAL
 
     speak_parser = argparse.ArgumentParser()
     speak_parser.add_argument('-p', '--piglatin', action='store_true', help='atinLay')