Fish completion support (google#122)

- Fish completion support (--completion fish)

README.md

@@ -82,7 +82,7 @@ Please see [The Python Fire Guide](docs/guide.md).
 | [Help](docs/using-cli.md#help-flag) | `command -- --help` |
 | [REPL](docs/using-cli.md#interactive-flag) | `command -- --interactive` | Enters interactive mode.
 | [Separator](docs/using-cli.md#separator-flag) | `command -- --separator=X` | This sets the separator to `X`. The default separator is `-`.
-| [Completion](docs/using-cli.md#completion-flag) | `command -- --completion` | Generate a completion script for the CLI.
+| [Completion](docs/using-cli.md#completion-flag) | `command -- --completion [shell]` | Generate a completion script for the CLI.
 | [Trace](docs/using-cli.md#trace-flag) | `command -- --trace` | Gets a Fire trace for the command.
 | [Verbose](docs/using-cli.md#verbose-flag) | `command -- --verbose` |
 

docs/api.md

@@ -13,7 +13,7 @@
 | [Help](using-cli.md#help-flag) | `command -- --help` |
 | [REPL](using-cli.md#interactive-flag) | `command -- --interactive` | Enters interactive mode.
 | [Separator](using-cli.md#separator-flag) | `command -- --separator=X` | This sets the separator to `X`. The default separator is `-`.
-| [Completion](using-cli.md#completion-flag) | `command -- --completion` | Generate a completion script for the CLI.
+| [Completion](using-cli.md#completion-flag) | `command -- --completion [shell]` | Generate a completion script for the CLI.
 | [Trace](using-cli.md#trace-flag) | `command -- --trace` | Gets a Fire trace for the command.
 | [Verbose](using-cli.md#verbose-flag) | `command -- --verbose` |
 

docs/guide.md

@@ -702,7 +702,7 @@ The complete set of flags available is shown below, in the reference section.
 | [Help](using-cli.md#help-flag) | `command -- --help` | Show help and usage information for the command.
 | [REPL](using-cli.md#interactive-flag) | `command -- --interactive` | Enter interactive mode.
 | [Separator](using-cli.md#separator-flag) | `command -- --separator=X` | This sets the separator to `X`. The default separator is `-`.
-| [Completion](using-cli.md#completion-flag) | `command -- --completion` | Generate a completion script for the CLI.
+| [Completion](using-cli.md#completion-flag) | `command -- --completion [shell]` | Generate a completion script for the CLI.
 | [Trace](using-cli.md#trace-flag) | `command -- --trace` | Gets a Fire trace for the command.
 | [Verbose](using-cli.md#verbose-flag) | `command -- --verbose` | Include private members in the output.
 

docs/index.md

@@ -82,7 +82,7 @@ Please see [The Python Fire Guide](guide.md).
 | [Help](using-cli.md#help-flag) | `command -- --help` |
 | [REPL](using-cli.md#interactive-flag) | `command -- --interactive` | Enters interactive mode.
 | [Separator](using-cli.md#separator-flag) | `command -- --separator=X` | This sets the separator to `X`. The default separator is `-`.
-| [Completion](using-cli.md#completion-flag) | `command -- --completion` | Generate a completion script for the CLI.
+| [Completion](using-cli.md#completion-flag) | `command -- --completion [shell]` | Generate a completion script for the CLI.
 | [Trace](using-cli.md#trace-flag) | `command -- --trace` | Gets a Fire trace for the command.
 | [Verbose](using-cli.md#verbose-flag) | `command -- --verbose` |
 

docs/using-cli.md

@@ -140,6 +140,9 @@ Call `widget -- --completion` to generate a completion script for the Fire CLI
 run `widget -- --completion > ~/.widget-completion`. You should then source this
 file; to get permanent completion, source this file from your .bashrc file.
 
+Call `widget -- --completion fish` to generate a completion script for the Fish
+shell. Source this file from your fish.config.
+
 If the commands available in the Fire CLI change, you'll have to regenerate the
 completion script and source it again.
 

fire/completion.py

@@ -26,11 +26,13 @@
 import six
 
 
-def Script(name, component, default_options=None):
-  return _Script(name, _Commands(component), default_options)
+def Script(name, component, default_options=None, shell='bash'):
+  if shell == 'fish':
+    return _FishScript(name, _Commands(component), default_options)
+  return _BashScript(name, _Commands(component), default_options)
 
 
-def _Script(name, commands, default_options=None):
+def _BashScript(name, commands, default_options=None):
   """Returns a Bash script registering a completion function for the commands.
 
   Args:
@@ -97,6 +99,61 @@ def _Script(name, commands, default_options=None):
   )
 
 
+def _FishScript(name, commands, default_options=None):
+  """Returns a Fish script registering a completion function for the commands.
+
+  Args:
+    name: The first token in the commands, also the name of the command.
+    commands: A list of all possible commands that tab completion can complete
+        to. Each command is a list or tuple of the string tokens that make up
+        that command.
+    default_options: A dict of options that can be used with any command. Use
+        this if there are flags that can always be appended to a command.
+  Returns:
+    A string which is the Fish script. Source the fish script to enable tab
+    completion in Fish.
+  """
+  default_options = default_options or set()
+  options_map = defaultdict(lambda: copy(default_options))
+  for command in commands:
+    start = (name + ' ' + ' '.join(command[:-1])).strip()
+    completion = _FormatForCommand(command[-1])
+    options_map[start].add(completion)
+    options_map[start.replace('_', '-')].add(completion)
+  fish_source = """function __fish_using_command
+    set cmd (commandline -opc)
+    if [ (count $cmd) -eq (count $argv) ]
+        for i in (seq (count $argv))
+            if [ $cmd[$i] != $argv[$i] ]
+                return 1
+            end
+        end
+        return 0
+    end
+    return 1
+end
+"""
+  subcommand_template = "complete -c {name} -n " \
+          "'__fish_using_command {start}' -f -a {subcommand}\n"
+  flag_template = "complete -c {name} -n " \
+          "'__fish_using_command {start}' -l {option}\n"
+  for start in options_map:
+    for option in sorted(options_map[start]):
+      if option.startswith('--'):
+        fish_source += flag_template.format(
+            name=name,
+            start=start,
+            option=option[2:]
+        )
+      else:
+        fish_source += subcommand_template.format(
+            name=name,
+            start=start,
+            subcommand=option
+        )
+  return fish_source
+
+
 def _IncludeMember(name, verbose):
   if verbose:
     return True

fire/completion_test.py

@@ -25,19 +25,32 @@
 
 class TabCompletionTest(testutils.BaseTestCase):
 
-  def testCompletionScript(self):
-    # A sanity check test to make sure the completion script satisfies some
-    # basic assumptions.
+  def testCompletionBashScript(self):
+    # A sanity check test to make sure the bash completion script satisfies
+    # some basic assumptions.
     commands = [
         ['run'],
         ['halt'],
         ['halt', '--now'],
     ]
-    script = completion._Script(name='command', commands=commands)  # pylint: disable=protected-access
+    script = completion._BashScript(name='command', commands=commands)  # pylint: disable=protected-access
     self.assertIn('command', script)
     self.assertIn('halt', script)
     self.assertIn('"$start" == "command"', script)
 
+  def testCompletionFishScript(self):
+    # A sanity check test to make sure the fish completion script satisfies
+    # some basic assumptions.
+    commands = [
+        ['run'],
+        ['halt'],
+        ['halt', '--now'],
+    ]
+    script = completion._FishScript(name='command', commands=commands)  # pylint: disable=protected-access
+    self.assertIn('command', script)
+    self.assertIn('halt', script)
+    self.assertIn('-l now', script)
+
   def testFnCompletions(self):
     def example(one, two, three):
       return one, two, three
@@ -113,6 +126,29 @@ def testClassScript(self):
     self.assertIn('--alpha', script)
     self.assertIn('--beta', script)
 
+  def testDeepDictFishScript(self):
+    deepdict = {'level1': {'level2': {'level3': {'level4': {}}}}}
+    script = completion.Script('deepdict', deepdict, shell='fish')
+    self.assertIn('level1', script)
+    self.assertIn('level2', script)
+    self.assertIn('level3', script)
+    self.assertNotIn('level4', script)  # The default depth is 3.
+
+  def testFnFishScript(self):
+    script = completion.Script('identity', tc.identity, shell='fish')
+    self.assertIn('arg1', script)
+    self.assertIn('arg2', script)
+    self.assertIn('arg3', script)
+    self.assertIn('arg4', script)
+
+  def testClassFishScript(self):
+    script = completion.Script('', tc.MixedDefaults, shell='fish')
+    self.assertIn('ten', script)
+    self.assertIn('sum', script)
+    self.assertIn('identity', script)
+    self.assertIn('alpha', script)
+    self.assertIn('beta', script)
+
   def testNonStringDictCompletions(self):
     completions = completion.Completions({
         10: 'green',

fire/core.py

@@ -44,6 +44,7 @@ def main(argv):
   -h --help: Provide help and usage information for the command.
   -i --interactive: Drop into a Python REPL after running the command.
   --completion: Write the Bash completion script for the tool to stdout.
+  --completion fish: Write the Fish completion script for the tool to stdout.
   --separator SEPARATOR: Use SEPARATOR in place of the default separator, '-'.
   --trace: Get the Fire Trace for the command.
 """
@@ -165,9 +166,9 @@ def Fire(component=None, command=None, name=None):
     return result
 
 
-def CompletionScript(name, component):
-  """Returns the text of the Bash completion script for a Fire CLI."""
-  return completion.Script(name, component)
+def CompletionScript(name, component, shell):
+  """Returns the text of the completion script for a Fire CLI."""
+  return completion.Script(name, component, shell=shell)
 
 
 class FireError(Exception):
@@ -338,7 +339,7 @@ def _Fire(component, args, context, name=None):
     initial_args = remaining_args
 
     if not remaining_args and (show_help or interactive or show_trace
-                               or show_completion):
+                               or show_completion is not None):
       # Don't initialize the final class or call the final function unless
       # there's a separator after it, and instead process the current component.
       break
@@ -469,10 +470,10 @@ def _Fire(component, args, context, name=None):
         initial_args)
     return component_trace
 
-  if show_completion:
+  if show_completion is not None:
     if name is None:
       raise ValueError('Cannot make completion script without command name')
-    script = CompletionScript(name, initial_component)
+    script = CompletionScript(name, initial_component, shell=show_completion)
     component_trace.AddCompletionScript(script)
 
   if interactive:

fire/parser.py

@@ -27,7 +27,7 @@ def CreateParser():
   parser.add_argument('--verbose', '-v', action='store_true')
   parser.add_argument('--interactive', '-i', action='store_true')
   parser.add_argument('--separator', default='-')
-  parser.add_argument('--completion', action='store_true')
+  parser.add_argument('--completion', nargs='?', const='bash', type=str)
   parser.add_argument('--help', '-h', action='store_true')
   parser.add_argument('--trace', '-t', action='store_true')
   # TODO: Consider allowing name to be passed as an argument.