def __getitem__(self, index):
'''
[n] returns a character (string of length 1)
[n:] returns a new StreamView instance that starts at the offset n
[n:m] returns a sequence (ie string, list, etc)
'''
# [n]
if isinstance(index, int):
(line, index) = self.__at(index, True)
return line.line[index]
if index.step is not None:
raise IndexError('Slice step not supported')
if index.start is None:
raise IndexError('Slice start must be specified')
# [n:]
if open_stop(index):
if index.start == 0 and self.__offset == 0:
return self
return StreamView(*self.__at(index.start))
# [n:m]
length = index.stop - index.start
if not length:
return self.__line.source.join([])
(line, start) = self.__at(index.start, True)
line_length = len(line.line)
remainder = length - (line_length - start)
lines = [line.line[start:min(start+length, line_length)]]
while line.line and remainder > 0:
line = line.next
if line.line:
line_length = len(line.line)
lines.append(line.line[0:min(remainder, line_length)])
remainder -= line_length
if remainder > 0:
raise IndexError(format('Missing {0:d} items', remainder))
else:
# in the code above we are careful to accumulate exactly what
# we need; you might think it simpler to accumulate whole lines
# and then take a slice below, but not all joins preserve length
# (consider SOL/EOL).
return line.source.join(lines)
def __getitem__(self, index):
'''
[n] returns a character (string of length 1)
[n:] returns a new StreamView instance that starts at the offset n
[n:m] returns a sequence (ie string, list, etc)
'''
# [n]
if isinstance(index, int):
(line, index) = self.__at(index, True)
return line.line[index]
if index.step is not None:
raise IndexError('Slice step not supported')
if index.start is None:
raise IndexError('Slice start must be specified')
# [n:]
if open_stop(index):
if index.start == 0 and self.__offset == 0:
return self
return StreamView(*self.__at(index.start))
# [n:m]
length = index.stop - index.start
if not length:
return self.__line.source.join([])
(line, start) = self.__at(index.start, True)
line_length = len(line.line)
remainder = length - (line_length - start)
lines = [line.line[start:min(start + length, line_length)]]
while line.line and remainder > 0:
line = line.next
if line.line:
line_length = len(line.line)
lines.append(line.line[0:min(remainder, line_length)])
remainder -= line_length
if remainder > 0:
raise IndexError(format('Missing {0:d} items', remainder))
else:
# in the code above we are careful to accumulate exactly what
# we need; you might think it simpler to accumulate whole lines
# and then take a slice below, but not all joins preserve length
# (consider SOL/EOL).
return line.source.join(lines)
def __getitem__(self, indices):
'''
**self[start:stop:algorithm, separator, ...]** - Repetition and lists.
This is a complex statement that modifies the current matcher so
that it matches several times. A separator may be specified
(eg for comma-separated lists) and the results may be combined with
"+" (so repeated matching of characters would give a word).
start:stop:algorithm
This controls the number of matches made and the order in which
different numbers of matches are returned.
[start]
Repeat exactly *start* times
[start:stop]
Repeat *start* to *stop* times (starting with as many matches
as possible, and then decreasing as necessary).
[start:stop:algorithm]
Direction selects the algorithm for searching.
'b' (BREADTH_FIRST)
A breadth first search is used, which tends to give shorter
matches before longer ones. This tries all possible matches for
the sub-matcher first (before repeating calls to consume more
of the stream). If the sub-matcher does not backtrack then this
guarantees that the number of matches returned will not decrease
(ie will monotonically increase) on backtracking.
'd' (DEPTH_FIRST)
A depth first search is used, which tends to give longer
matches before shorter ones. This tries to repeats matches
with the sub-matcher, consuming as much of the stream as
possible, before backtracking to find alternative matchers.
If the sub-matcher does not backtrack then this guarantees
that the number of matches returned will not increase (ie will
monotonically decrease) on backtracking.
'g' (GREEDY)
An exhaustive search is used, which finds all results (by
breadth first search) and orders them by length before returning
them ordered from longest to shortest. This guarantees that
the number of matches returned will not increase (ie will
monotonically decrease) on backtracking, but can consume a lot
of resources.
'n' (NON_GREEDY)
As for 'g' (GREEDY), but results are ordered shortest to
longest. This guarantees that the number of matches returned
will not decrease (ie will monotonically increase) on
backtracking, but can consume a lot of resources,
Values may be omitted; the defaults are: *start* = 0, *stop* =
infinity, *algorithm* = 'd' (DEPTH_FIRST).
separator
If given, this must appear between repeated values. Matched
separators are returned as part of the result (unless, of course,
they are implemented with a matcher that returns nothing). If
*separator* is a string it is converted to a literal match.
...
If ... (an ellipsis) is given then the results are joined together
with "+".
Examples
--------
Any()[0:3,...] will match 3 or less characters, joining them
together so that the result is a single string.
Word()[:,','] will match a comma-separated list of words.
value[:] or value[0:] or value[0::'d'] is a "greedy" match that,
if value does not backtrack, is equivalent to the "*" in a regular
expression.
value[::'n'] is the "non-greedy" equivalent (preferring as short a
match as possible) and value[::'g'] is greedy even when value does
provide alternative matches on backtracking.
'''
start = 0
stop = None
step = DEPTH_FIRST
separator = None
add = False
have_index = False
if not isinstance(indices, tuple):
indices = [indices]
for index in indices:
if isinstance(index, int):
if have_index:
raise TypeError(
fmt('Multiple slices not supported: {0!r}', index))
start = index
stop = index
step = DEPTH_FIRST
have_index = True
elif isinstance(index, slice):
if have_index:
raise TypeError(
fmt('Multiple slices not supported: {0!r}', index))
start = index.start if index.start is not None else 0
stop = index.stop if not open_stop(index) else None
step = index.step if index.step is not None else DEPTH_FIRST
have_index = True
elif index == Ellipsis:
add = True
elif separator is None:
separator = index
else:
raise TypeError(index)
# important for rewriting
if stop == 1:
add = False
return self._lookup(REPEAT)(self, start, stop, step, separator, add,
self._lookup(REDUCE))
def __getitem__(self, indices):
'''
**self[start:stop:algorithm, separator, ...]** - Repetition and lists.
This is a complex statement that modifies the current matcher so
that it matches several times. A separator may be specified
(eg for comma-separated lists) and the results may be combined with
"+" (so repeated matching of characters would give a word).
start:stop:algorithm
This controls the number of matches made and the order in which
different numbers of matches are returned.
[start]
Repeat exactly *start* times
[start:stop]
Repeat *start* to *stop* times (starting with as many matches
as possible, and then decreasing as necessary).
[start:stop:algorithm]
Direction selects the algorithm for searching.
'b' (BREADTH_FIRST)
A breadth first search is used, which tends to give shorter
matches before longer ones. This tries all possible matches for
the sub-matcher first (before repeating calls to consume more
of the stream). If the sub-matcher does not backtrack then this
guarantees that the number of matches returned will not decrease
(ie will monotonically increase) on backtracking.
'd' (DEPTH_FIRST)
A depth first search is used, which tends to give longer
matches before shorter ones. This tries to repeats matches
with the sub-matcher, consuming as much of the stream as
possible, before backtracking to find alternative matchers.
If the sub-matcher does not backtrack then this guarantees
that the number of matches returned will not increase (ie will
monotonically decrease) on backtracking.
'g' (GREEDY)
An exhaustive search is used, which finds all results (by
breadth first search) and orders them by length before returning
them ordered from longest to shortest. This guarantees that
the number of matches returned will not increase (ie will
monotonically decrease) on backtracking, but can consume a lot
of resources.
'n' (NON_GREEDY)
As for 'g' (GREEDY), but results are ordered shortest to
longest. This guarantees that the number of matches returned
will not decrease (ie will monotonically increase) on
backtracking, but can consume a lot of resources,
Values may be omitted; the defaults are: *start* = 0, *stop* =
infinity, *algorithm* = 'd' (DEPTH_FIRST).
separator
If given, this must appear between repeated values. Matched
separators are returned as part of the result (unless, of course,
they are implemented with a matcher that returns nothing). If
*separator* is a string it is converted to a literal match.
...
If ... (an ellipsis) is given then the results are joined together
with "+".
Examples
--------
Any()[0:3,...] will match 3 or less characters, joining them
together so that the result is a single string.
Word()[:,','] will match a comma-separated list of words.
value[:] or value[0:] or value[0::'d'] is a "greedy" match that,
if value does not backtrack, is equivalent to the "*" in a regular
expression.
value[::'n'] is the "non-greedy" equivalent (preferring as short a
match as possible) and value[::'g'] is greedy even when value does
provide alternative matches on backtracking.
'''
start = 0
stop = None
step = DEPTH_FIRST
separator = None
add = False
if not isinstance(indices, tuple):
indices = [indices]
for index in indices:
if isinstance(index, int):
start = index
stop = index
step = DEPTH_FIRST
elif isinstance(index, slice):
start = index.start if index.start != None else 0
stop = index.stop if not open_stop(index) else None
step = index.step if index.step != None else DEPTH_FIRST
elif index == Ellipsis:
add = True
elif separator is None:
separator = index
else:
raise TypeError(index)
return self._lookup(REPEAT)(self, start, stop, step, separator, add)
def __getitem__(self, spec):
if isinstance(spec, slice) and open_stop(spec):
return Facade(self.__stream.__getitem__(spec), self.__memory)
else:
return self.__stream.__getitem__(spec)
def __getitem__(self, spec):
if isinstance(spec, slice) and open_stop(spec):
return Facade(self.__stream.__getitem__(spec), self.__memory)
else:
return self.__stream.__getitem__(spec)
