Source code for xonsh.shell
# -*- coding: utf-8 -*-
"""The xonsh shell"""
import os
import random
import builtins
import warnings
from xonsh.xontribs import update_context
from xonsh.environ import xonshrc_context
from xonsh.execer import Execer
from xonsh.platform import (best_shell_type, has_prompt_toolkit,
ptk_version_is_supported, ptk_version_info)
from xonsh.tools import XonshError, to_bool_or_int
[docs]class Shell(object):
"""Main xonsh shell.
Initializes execution environment and decides if prompt_toolkit or
readline version of shell should be used.
"""
def __init__(self, ctx=None, shell_type=None, config=None, rc=None,
**kwargs):
"""
Parameters
----------
ctx : Mapping, optional
The execution context for the shell (e.g. the globals namespace).
If none, this is computed by loading the rc files. If not None,
this no additional context is computed and this is used
directly.
shell_type : str, optional
The shell type to start, such as 'readline', 'prompt_toolkit',
or 'random'.
config : str, optional
Path to configuration file.
rc : list of str, optional
Sequence of paths to run control files.
"""
self.login = kwargs.get('login', True)
self.stype = shell_type
self._init_environ(ctx, config, rc,
kwargs.get('scriptcache', True),
kwargs.get('cacheall', False))
env = builtins.__xonsh_env__
# pick a valid shell -- if no shell is specified by the user,
# shell type is pulled from env
if shell_type is None:
shell_type = env.get('SHELL_TYPE')
if shell_type == 'best' or shell_type is None:
shell_type = best_shell_type()
elif shell_type == 'random':
shell_type = random.choice(('readline', 'prompt_toolkit'))
if shell_type == 'prompt_toolkit':
if not has_prompt_toolkit():
warnings.warn('prompt_toolkit is not available, using '
'readline instead.')
shell_type = 'readline'
elif not ptk_version_is_supported():
warnings.warn('prompt-toolkit version < v1.0.0 is not '
'supported. Please update prompt-toolkit. Using '
'readline instead.')
shell_type = 'readline'
env['SHELL_TYPE'] = shell_type
# actually make the shell
if shell_type == 'none':
from xonsh.base_shell import BaseShell as shell_class
elif shell_type == 'prompt_toolkit':
from xonsh.ptk.shell import PromptToolkitShell as shell_class
elif shell_type == 'readline':
from xonsh.readline_shell import ReadlineShell as shell_class
else:
raise XonshError('{} is not recognized as a shell type'.format(
shell_type))
self.shell = shell_class(execer=self.execer,
ctx=self.ctx, **kwargs)
# allows history garbace colector to start running
builtins.__xonsh_history__.gc.wait_for_shell = False
def __getattr__(self, attr):
"""Delegates calls to appropriate shell instance."""
return getattr(self.shell, attr)
def _init_environ(self, ctx, config, rc, scriptcache, cacheall):
self.ctx = {} if ctx is None else ctx
debug = to_bool_or_int(os.getenv('XONSH_DEBUG', '0'))
self.execer = Execer(config=config, login=self.login, xonsh_ctx=self.ctx,
debug_level=debug)
self.execer.scriptcache = scriptcache
self.execer.cacheall = cacheall
if self.stype != 'none' or self.login:
# load xontribs from config file
names = builtins.__xonsh_config__.get('xontribs', ())
for name in names:
update_context(name, ctx=self.ctx)
# load run control files
env = builtins.__xonsh_env__
rc = env.get('XONSHRC') if rc is None else rc
self.ctx.update(xonshrc_context(rcfiles=rc, execer=self.execer, initial=self.ctx))
self.ctx['__name__'] = '__main__'