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from __future__ import absolute_import, division, print_function
import re
import random
from glue.core.component_link import ComponentLink
from glue.core.subset import Subset, SubsetState
from glue.core.data import ComponentID
TAG_RE = re.compile('\{\s*(?P<tag>\S+)\s*\}')
__all__ = ['ParsedCommand', 'ParsedSubsetState']
def _ensure_only_component_references(cmd, references):
""" Search through tag references in a command, ensure that
they all reference ComponentIDs
Parameters
----------
cmd : string. A template command
referenes : a mapping from tags to substitution objects
Raises
------
TypeError, if cmd does not refer only to ComponentIDs
"""
for match in TAG_RE.finditer(cmd):
tag = match.group('tag')
if tag not in references or not \
isinstance(references[tag], ComponentID):
raise TypeError(
"Reference to %s, which is not a ComponentID" % tag)
def _reference_list(cmd, references):
""" Return a list of the values in the references mapping whose
keys appear in the command
Parameters
----------
cmd : string. A template command
references : a mapping from tags to substitution objects
Returns
-------
A list of the unique values in references that appear in the command
Examples
--------
>>> cmd = '{g} - {r} + {g}'
>>> references = {'g' : g_object, 'r' : r_object, 'i' : i_object}
>>> _reference_list(cmd, references)
[g_object, r_object]
Raises
------
KeyError: if tags in the command aren't in the reference mapping
"""
try:
return list(set(references[m.group('tag')]
for m in TAG_RE.finditer(cmd)))
except KeyError:
raise KeyError("Tags from command not in reference mapping")
def _dereference(cmd, references):
""" Dereference references in the template command, to refer
to objects in the reference mapping
Parameters
----------
cmd : Command string
references : mapping from template tags to objects
Returns
-------
A new command, where all the tags have been subsituted as follows:
"{tag}" -> 'data[references["tag"], __view]', if references[tag] is a ComponentID
"{tag}" -> 'references["tag"].to_mask(__view)' if references[tag] is a Subset
__view is a placeholder variable referencing the view
passed to data.__getitem__ and subset.to_mask
Raises
------
TypeError, if a tag in the command maps to something other than
a ComponentID or Subset object
"""
def sub_func(match):
tag = match.group('tag')
if isinstance(references[tag], ComponentID):
return 'data[references["%s"], __view]' % tag
elif isinstance(references[tag], Subset):
return 'references["%s"].to_mask(__view)' % tag
else:
raise TypeError("Tag %s maps to unrecognized type: %s" %
(tag, type(references[tag])))
return TAG_RE.sub(sub_func, cmd)
def _dereference_random(cmd):
"""
Dereference references in the template command, to refer
to random floating-point values. This is used to quickly test that the
command evaluates without errors.
Parameters
----------
cmd : str
Command string
Returns
-------
A new command, where all the tags have been subsituted by floating point values
"""
def sub_func(match):
tag = match.group('tag')
return str(random.random())
return TAG_RE.sub(sub_func, cmd)
class InvalidTagError(ValueError):
def __init__(self, tag, references):
msg = ("Tag %s not in reference mapping: %s" %
(tag, sorted(references.keys())))
self.tag = tag
self.references = references
super(InvalidTagError, self).__init__(msg)
def _validate(cmd, references):
""" Make sure all references in the command are in the reference mapping
Raises
------
TypeError, if a tag is missing from references
"""
for match in TAG_RE.finditer(cmd):
tag = match.group('tag')
if tag not in references:
raise InvalidTagError(tag, references)
class ParsedCommand(object):
""" Class to manage commands that define new components and subsets """
def __init__(self, cmd, references):
""" Create a new parsed command object
Parameters
----------
cmd : str. A template command. Can only reference ComponentID objects
references : mapping from command templates to substitution objects
"""
_validate(cmd, references)
self._cmd = cmd
self._references = references
def ensure_only_component_references(self):
_ensure_only_component_references(self._cmd, self._references)
@property
def reference_list(self):
return _reference_list(self._cmd, self._references)
def evaluate(self, data, view=None):
from glue import env
# pylint: disable=W0613, W0612
references = self._references
cmd = _dereference(self._cmd, self._references)
scope = vars(env)
scope['__view'] = view
global_variables = vars(env)
# We now import math modules if not already defined in local or
# global variables
if 'numpy' not in global_variables and 'numpy' not in locals():
import numpy
if 'np' not in global_variables and 'np' not in locals():
import numpy as np
if 'math' not in global_variables and 'math' not in locals():
import math
return eval(cmd, global_variables, locals()) # careful!
def evaluate_test(self, view=None):
from glue import env
cmd = _dereference_random(self._cmd)
scope = vars(env)
scope['__view'] = view
global_variables = vars(env)
# We now import math modules if not already defined in local or
# global variables
if 'numpy' not in global_variables and 'numpy' not in locals():
import numpy
if 'np' not in global_variables and 'np' not in locals():
import numpy as np
if 'math' not in global_variables and 'math' not in locals():
import math
return eval(cmd, global_variables, locals()) # careful!
def __gluestate__(self, context):
return dict(cmd=self._cmd,
references=dict((k, context.id(v))
for k, v in self._references.items()))
@classmethod
def __setgluestate__(cls, rec, context):
cmd = rec['cmd']
ref = dict((k, context.object(v))
for k, v in rec['references'].items())
return cls(cmd, ref)
class ParsedComponentLink(ComponentLink):
""" Class to create a new ComponentLink from a ParsedCommand object. """
def __init__(self, to_, parsed):
""" Create a new link
Parameters
----------
to_ : ComponentID instance to associate with the new component
parsed : A ParsedCommand object
"""
parsed.ensure_only_component_references()
super(ParsedComponentLink, self).__init__(
parsed.reference_list, to_, lambda: None)
self._parsed = parsed
def compute(self, data, view=None):
return self._parsed.evaluate(data, view)
def __gluestate__(self, context):
return dict(parsed=context.do(self._parsed),
to=context.id(self.get_to_id()))
@classmethod
def __setgluestate__(cls, rec, context):
return cls(context.object(rec['to']),
context.object(rec['parsed']))
class ParsedSubsetState(SubsetState):
""" A SubsetState defined by a ParsedCommand object """
def __init__(self, parsed):
""" Create a new object
Parameters
----------
parsed : A ParsedCommand object
"""
super(ParsedSubsetState, self).__init__()
self._parsed = parsed
def to_mask(self, data, view=None):
""" Calculate the new mask by evaluating the dereferenced command """
result = self._parsed.evaluate(data)
if view is not None:
result = result[view]
return result
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