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Diffstat (limited to 'lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/sql/visitors.py')
| -rwxr-xr-x | lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/sql/visitors.py | 266 |
1 files changed, 0 insertions, 266 deletions
diff --git a/lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/sql/visitors.py b/lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/sql/visitors.py deleted file mode 100755 index 0c6be97d..00000000 --- a/lib/python2.7/site-packages/SQLAlchemy-0.7.0-py2.7-linux-x86_64.egg/sqlalchemy/sql/visitors.py +++ /dev/null @@ -1,266 +0,0 @@ -# sql/visitors.py -# Copyright (C) 2005-2011 the SQLAlchemy authors and contributors <see AUTHORS file> -# -# This module is part of SQLAlchemy and is released under -# the MIT License: http://www.opensource.org/licenses/mit-license.php - -"""Visitor/traversal interface and library functions. - -SQLAlchemy schema and expression constructs rely on a Python-centric -version of the classic "visitor" pattern as the primary way in which -they apply functionality. The most common use of this pattern -is statement compilation, where individual expression classes match -up to rendering methods that produce a string result. Beyond this, -the visitor system is also used to inspect expressions for various -information and patterns, as well as for usage in -some kinds of expression transformation. Other kinds of transformation -use a non-visitor traversal system. - -For many examples of how the visit system is used, see the -sqlalchemy.sql.util and the sqlalchemy.sql.compiler modules. -For an introduction to clause adaption, see -http://techspot.zzzeek.org/?p=19 . - -""" - -from collections import deque -import re -from sqlalchemy import util -import operator - -__all__ = ['VisitableType', 'Visitable', 'ClauseVisitor', - 'CloningVisitor', 'ReplacingCloningVisitor', 'iterate', - 'iterate_depthfirst', 'traverse_using', 'traverse', - 'cloned_traverse', 'replacement_traverse'] - -class VisitableType(type): - """Metaclass which checks for a `__visit_name__` attribute and - applies `_compiler_dispatch` method to classes. - - """ - - def __init__(cls, clsname, bases, clsdict): - if cls.__name__ == 'Visitable' or not hasattr(cls, '__visit_name__'): - super(VisitableType, cls).__init__(clsname, bases, clsdict) - return - - _generate_dispatch(cls) - - super(VisitableType, cls).__init__(clsname, bases, clsdict) - -def _generate_dispatch(cls): - # set up an optimized visit dispatch function - # for use by the compiler - if '__visit_name__' in cls.__dict__: - visit_name = cls.__visit_name__ - if isinstance(visit_name, str): - getter = operator.attrgetter("visit_%s" % visit_name) - def _compiler_dispatch(self, visitor, **kw): - return getter(visitor)(self, **kw) - else: - def _compiler_dispatch(self, visitor, **kw): - return getattr(visitor, 'visit_%s' % self.__visit_name__)(self, **kw) - - cls._compiler_dispatch = _compiler_dispatch - -class Visitable(object): - """Base class for visitable objects, applies the - ``VisitableType`` metaclass. - - """ - - __metaclass__ = VisitableType - -class ClauseVisitor(object): - """Base class for visitor objects which can traverse using - the traverse() function. - - """ - - __traverse_options__ = {} - - def traverse_single(self, obj, **kw): - for v in self._visitor_iterator: - meth = getattr(v, "visit_%s" % obj.__visit_name__, None) - if meth: - return meth(obj, **kw) - - def iterate(self, obj): - """traverse the given expression structure, returning an iterator of all elements.""" - - return iterate(obj, self.__traverse_options__) - - def traverse(self, obj): - """traverse and visit the given expression structure.""" - - return traverse(obj, self.__traverse_options__, self._visitor_dict) - - @util.memoized_property - def _visitor_dict(self): - visitors = {} - - for name in dir(self): - if name.startswith('visit_'): - visitors[name[6:]] = getattr(self, name) - return visitors - - @property - def _visitor_iterator(self): - """iterate through this visitor and each 'chained' visitor.""" - - v = self - while v: - yield v - v = getattr(v, '_next', None) - - def chain(self, visitor): - """'chain' an additional ClauseVisitor onto this ClauseVisitor. - - the chained visitor will receive all visit events after this one. - - """ - tail = list(self._visitor_iterator)[-1] - tail._next = visitor - return self - -class CloningVisitor(ClauseVisitor): - """Base class for visitor objects which can traverse using - the cloned_traverse() function. - - """ - - def copy_and_process(self, list_): - """Apply cloned traversal to the given list of elements, and return the new list.""" - - return [self.traverse(x) for x in list_] - - def traverse(self, obj): - """traverse and visit the given expression structure.""" - - return cloned_traverse(obj, self.__traverse_options__, self._visitor_dict) - -class ReplacingCloningVisitor(CloningVisitor): - """Base class for visitor objects which can traverse using - the replacement_traverse() function. - - """ - - def replace(self, elem): - """receive pre-copied elements during a cloning traversal. - - If the method returns a new element, the element is used - instead of creating a simple copy of the element. Traversal - will halt on the newly returned element if it is re-encountered. - """ - return None - - def traverse(self, obj): - """traverse and visit the given expression structure.""" - - def replace(elem): - for v in self._visitor_iterator: - e = v.replace(elem) - if e is not None: - return e - return replacement_traverse(obj, self.__traverse_options__, replace) - -def iterate(obj, opts): - """traverse the given expression structure, returning an iterator. - - traversal is configured to be breadth-first. - - """ - stack = deque([obj]) - while stack: - t = stack.popleft() - yield t - for c in t.get_children(**opts): - stack.append(c) - -def iterate_depthfirst(obj, opts): - """traverse the given expression structure, returning an iterator. - - traversal is configured to be depth-first. - - """ - stack = deque([obj]) - traversal = deque() - while stack: - t = stack.pop() - traversal.appendleft(t) - for c in t.get_children(**opts): - stack.append(c) - return iter(traversal) - -def traverse_using(iterator, obj, visitors): - """visit the given expression structure using the given iterator of objects.""" - - for target in iterator: - meth = visitors.get(target.__visit_name__, None) - if meth: - meth(target) - return obj - -def traverse(obj, opts, visitors): - """traverse and visit the given expression structure using the default iterator.""" - - return traverse_using(iterate(obj, opts), obj, visitors) - -def traverse_depthfirst(obj, opts, visitors): - """traverse and visit the given expression structure using the depth-first iterator.""" - - return traverse_using(iterate_depthfirst(obj, opts), obj, visitors) - -def cloned_traverse(obj, opts, visitors): - """clone the given expression structure, allowing modifications by visitors.""" - - cloned = util.column_dict() - - def clone(element): - if element not in cloned: - cloned[element] = element._clone() - return cloned[element] - - obj = clone(obj) - stack = [obj] - - while stack: - t = stack.pop() - if t in cloned: - continue - t._copy_internals(clone=clone) - - meth = visitors.get(t.__visit_name__, None) - if meth: - meth(t) - - for c in t.get_children(**opts): - stack.append(c) - return obj - -def replacement_traverse(obj, opts, replace): - """clone the given expression structure, allowing element replacement by a given replacement function.""" - - cloned = util.column_dict() - stop_on = util.column_set(opts.get('stop_on', [])) - - def clone(element): - newelem = replace(element) - if newelem is not None: - stop_on.add(newelem) - return newelem - - if element not in cloned: - cloned[element] = element._clone() - return cloned[element] - - obj = clone(obj) - stack = [obj] - while stack: - t = stack.pop() - if t in stop_on: - continue - t._copy_internals(clone=clone) - for c in t.get_children(**opts): - stack.append(c) - return obj |