Coverage for local/lib/python2.7/site-packages/sage/repl/display/pretty_print.py : 93%

# -*- coding: utf-8 -*- 

""" 

The Sage pretty printer 

Any transformation to a string goes through here. In other words, the 

:class:`~sage.repl.displayhook.formatter.SagePlainTextFormatter` is 

entirely implemented via :class:`SagePrettyPrinter`. Other formatters 

may or may not use :class:`SagePrettyPrinter` to generate text output. 

AUTHORS: 

- Bill Cauchois (2009): initial version 

- Jean-Baptiste Priez <jbp@kerios.fr> (2013): ASCII art 

- Volker Braun (2013): refactored into DisplayHookBase 

""" 

#***************************************************************************** 

# Copyright (C) 2014 Volker Braun <vbraun.name@gmail.com> 

# 

# Distributed under the terms of the GNU General Public License (GPL) 

# as published by the Free Software Foundation; either version 2 of 

# the License, or (at your option) any later version. 

# http://www.gnu.org/licenses/ 

#***************************************************************************** 

from IPython.lib.pretty import PrettyPrinter 

from sage.repl.display.fancy_repr import * 

class SagePrettyPrinter(PrettyPrinter): 

DEBUG = False 

# These object representers will be tried, in this order, until 

# one is found that is able to deal with the object. 

pretty_repr = ( 

TallListRepr(), 

LargeMatrixHelpRepr(), 

SomeIPythonRepr(), 

PlainPythonRepr(), 

) 

def toplevel(self): 

r""" 

Return whether we are currently at the top level. 

OUTPUT: 

Boolean. Whether we are currently pretty-printing an object at 

the outermost level (``True``), or whether the object is 

inside a container (``False``). 

EXAMPLES:: 

sage: from sage.repl.display.pretty_print import SagePrettyPrinter 

sage: from six import StringIO 

sage: stream = StringIO() 

sage: spp = SagePrettyPrinter(stream, 78, '\n') 

sage: spp.toplevel() 

True 

""" 

return len(self.stack) <= 1 # only the object currently being represented 

def __init__(self, output, max_width, newline, max_seq_length=None): 

""" 

Pretty print Sage objects for the commandline 

INPUT: 

See IPython documentation. 

EXAMPLES:: 

sage: 123 

123 

IPython pretty printers:: 

sage: set({1, 2, 3}) 

{1, 2, 3} 

sage: dict(zzz=123, aaa=99, xab=10) # sorted by keys 

{'aaa': 99, 'xab': 10, 'zzz': 123} 

These are overridden in IPython in a way that we feel is somewhat 

confusing, and we prefer to print them like plain Python which is 

more informative. See :trac:`14466` :: 

sage: 'this is a string' 

'this is a string' 

sage: type(123) 

<type 'sage.rings.integer.Integer'> 

sage: type 

<... 'type'> 

sage: import types 

sage: type('name', (), {}) 

<class '__main__.name'> 

sage: types.BuiltinFunctionType 

<type 'builtin_function_or_method'> 

sage: def foo(): pass 

sage: foo 

<function foo at 0x...> 

""" 

super(SagePrettyPrinter, self).__init__( 

output, max_width, newline, max_seq_length=max_seq_length) 

self.stack = [] 

def pretty(self, obj): 

r""" 

Pretty print ``obj`` 

This is the only method that outside code should invoke. 

INPUT: 

- ``obj`` -- anything. 

OUTPUT: 

String representation for object. 

EXAMPLES:: 

sage: from sage.repl.display.pretty_print import SagePrettyPrinter 

sage: from six import StringIO 

sage: stream = StringIO() 

sage: SagePrettyPrinter(stream, 78, '\n').pretty([type, 123, 'foo']) 

sage: stream.getvalue() 

"[<... 'type'>," 

""" 

obj_id = id(obj) 

cycle = obj_id in self.stack 

self.stack.append(obj_id) 

self.begin_group() 

try: 

ok = False 

for representation in self.pretty_repr: 

if self.DEBUG: print('Trying {0}'.format(representation)) 

ok = representation(obj, self, cycle) 

if self.DEBUG: print('ok = {0}'.format(ok)) 

if ok not in [True, False]: 

raise RuntimeError('printer failed to return boolean') 

if ok: 

break 

if not ok: 

raise RuntimeError('no printer registered for object') 

finally: 

self.end_group() 

self.stack.pop()