def to_tree(expr, names=None):
""" Represent Blaze expression with core data structures
Transform a Blaze expression into a form using only strings, dicts, lists
and base types (int, float, datetime, ....) This form can be useful for
serialization.
Parameters
----------
expr : Expr
A Blaze expression
Examples
--------
>>> t = symbol('t', 'var * {x: int32, y: int32}')
>>> to_tree(t) # doctest: +SKIP
{'op': 'Symbol',
'args': ['t', 'var * { x : int32, y : int32 }', False]}
>>> to_tree(t.x.sum()) # doctest: +SKIP
{'op': 'sum',
'args': [{'op': 'Column',
'args': [{'op': 'Symbol'
'args': ['t',
'var * { x : int32, y : int32 }',
False]}
'x']}]}
Simplify expresion using explicit ``names`` dictionary. In the example
below we replace the ``Symbol`` node with the string ``'t'``.
>>> tree = to_tree(t.x, names={t: 't'})
>>> tree # doctest: +SKIP
{'op': 'Column', 'args': ['t', 'x']}
>>> from_tree(tree, namespace={'t': t})
t.x
See Also
--------
from_tree
"""
if isinstance(expr, slice):
# NOTE: This case must come first, since `slice` objects are not
# hashable, so a dict lookup inside `names` will raise an execption.
return {u'op': 'slice',
u'args': [to_tree(arg, names=names) for arg in
[expr.start, expr.stop, expr.step]]}
if names and expr in names:
return names[expr]
if isinstance(expr, tuple):
return [to_tree(arg, names=names) for arg in expr]
if isinstance(expr, expr_utils._slice):
return to_tree(expr.as_slice(), names=names)
elif isinstance(expr, _Data):
return to_tree(symbol(u8(expr._name), expr.dshape), names)
elif isinstance(expr, Expr):
return {u'op': u8(type(expr).__name__),
u'args': [to_tree(arg, names) for arg in expr._args]}
elif isinstance(expr, str):
return u8(expr)
else:
return expr
def json_dumps_trusted(f):
# let the server serialize any callable - this is only used for testing
# at present - do the error handling when json comes from client so in
# object_hook, catch anything that is not pandas_numpy
fcn = u8(".".join([f.__module__, f.__name__]))
return {u'__!callable': fcn}
def json_dumps_trusted(f):
# let the server serialize any callable - this is only used for testing
# at present - do the error handling when json comes from client so in
# object_hook, catch anything that is not pandas_numpy
fcn = u8(".".join([f.__module__, f.__name__]))
return {u'__!callable': fcn}
def to_tree(expr, names=None):
""" Represent Blaze expression with core data structures
Transform a Blaze expression into a form using only strings, dicts, lists
and base types (int, float, datetime, ....) This form can be useful for
serialization.
Parameters
----------
expr : Expr
A Blaze expression
Examples
--------
>>> t = symbol('t', 'var * {x: int32, y: int32}')
>>> to_tree(t) # doctest: +SKIP
{'op': 'Symbol',
'args': ['t', 'var * { x : int32, y : int32 }', False]}
>>> to_tree(t.x.sum()) # doctest: +SKIP
{'op': 'sum',
'args': [{'op': 'Column',
'args': [{'op': 'Symbol'
'args': ['t',
'var * { x : int32, y : int32 }',
False]}
'x']}]}
Simplify expresion using explicit ``names`` dictionary. In the example
below we replace the ``Symbol`` node with the string ``'t'``.
>>> tree = to_tree(t.x, names={t: 't'})
>>> tree # doctest: +SKIP
{'op': 'Column', 'args': ['t', 'x']}
>>> from_tree(tree, namespace={'t': t})
t.x
See Also
--------
from_tree
"""
if isinstance(expr, slice):
# NOTE: This case must come first, since `slice` objects are not
# hashable, so a dict lookup inside `names` will raise an execption.
return {u'op': 'slice',
u'args': [to_tree(arg, names=names) for arg in
[expr.start, expr.stop, expr.step]]}
if names and expr in names:
return names[expr]
if isinstance(expr, tuple):
return [to_tree(arg, names=names) for arg in expr]
if isinstance(expr, expr_utils._slice):
return to_tree(expr.as_slice(), names=names)
elif isinstance(expr, _Data):
return to_tree(symbol(u8(expr._name), expr.dshape), names)
elif isinstance(expr, Expr):
return {u'op': u8(type(expr).__name__),
u'args': [to_tree(arg, names) for arg in expr._args]}
elif isinstance(expr, str):
return u8(expr)
else:
return expr
