Source code for sympy.interactive.printing

"""Tools for setting up printing in interactive sessions. """

from __future__ import print_function, division

import sys
from distutils.version import LooseVersion as V
from io import BytesIO

from sympy import latex as default_latex
from sympy import preview
from sympy.core.compatibility import integer_types
from sympy.utilities.misc import debug


def _init_python_printing(stringify_func, **settings):
    """Setup printing in Python interactive session. """
    import sys
    from sympy.core.compatibility import builtins

    def _displayhook(arg):
        """Python's pretty-printer display hook.

           This function was adapted from:

            http://www.python.org/dev/peps/pep-0217/

        """
        if arg is not None:
            builtins._ = None
            print(stringify_func(arg, **settings))
            builtins._ = arg

    sys.displayhook = _displayhook


def _init_ipython_printing(ip, stringify_func, use_latex, euler, forecolor,
                           backcolor, fontsize, latex_mode, print_builtin,
                           latex_printer, **settings):
    """Setup printing in IPython interactive session. """
    try:
        from IPython.lib.latextools import latex_to_png
    except ImportError:
        pass

    preamble = "\\documentclass[%s]{article}\n" \
               "\\pagestyle{empty}\n" \
               "\\usepackage{amsmath,amsfonts}%s\\begin{document}"
    if euler:
        addpackages = '\\usepackage{euler}'
    else:
        addpackages = ''
    preamble = preamble % (fontsize, addpackages)

    imagesize = 'tight'
    offset = "0cm,0cm"
    resolution = 150
    dvi = r"-T %s -D %d -bg %s -fg %s -O %s" % (
        imagesize, resolution, backcolor, forecolor, offset)
    dvioptions = dvi.split()
    debug("init_printing: DVIOPTIONS:", dvioptions)
    debug("init_printing: PREAMBLE:", preamble)

    latex = latex_printer or default_latex

    def _print_plain(arg, p, cycle):
        """caller for pretty, for use in IPython 0.11"""
        if _can_print_latex(arg):
            p.text(stringify_func(arg))
        else:
            p.text(IPython.lib.pretty.pretty(arg))

    def _preview_wrapper(o):
        exprbuffer = BytesIO()
        try:
            preview(o, output='png', viewer='BytesIO',
                    outputbuffer=exprbuffer, preamble=preamble,
                    dvioptions=dvioptions)
        except Exception as e:
            # IPython swallows exceptions
            debug("png printing:", "_preview_wrapper exception raised:",
                  repr(e))
            raise
        return exprbuffer.getvalue()

    def _matplotlib_wrapper(o):
        # mathtext does not understand certain latex flags, so we try to
        # replace them with suitable subs
        o = o.replace(r'\operatorname', '')
        o = o.replace(r'\overline', r'\bar')
        # mathtext can't render some LaTeX commands. For example, it can't
        # render any LaTeX environments such as array or matrix. So here we
        # ensure that if mathtext fails to render, we return None.
        try:
            return latex_to_png(o)
        except ValueError as e:
            debug('matplotlib exception caught:', repr(e))
            return None

    def _can_print_latex(o):
        """Return True if type o can be printed with LaTeX.

        If o is a container type, this is True if and only if every element of
        o can be printed with LaTeX.
        """

        try:
            from sympy import Basic
            from sympy.matrices import MatrixBase
            from sympy.physics.vector import Vector, Dyadic
            from sympy.tensor.array import NDimArray
            # If you're adding another type, make sure you add it to printable_types
            # later in this file as well

            if isinstance(o, (list, tuple, set, frozenset)):
               return all(_can_print_latex(i) for i in o)
            elif isinstance(o, dict):
               return all(_can_print_latex(i) and _can_print_latex(o[i]) for i in o)
            elif isinstance(o, bool):
               return False
            # TODO : Investigate if "elif hasattr(o, '_latex')" is more useful
            # to use here, than these explicit imports.
            elif isinstance(o, (Basic, MatrixBase, Vector, Dyadic, NDimArray)):
               return True
            elif isinstance(o, (float, integer_types)) and print_builtin:
               return True
            return False
        except RuntimeError:
            return False
            # This is in case maximum recursion depth is reached.
            # Since RecursionError is for versions of Python 3.5+
            # so this is to guard against RecursionError for older versions.

    def _print_latex_png(o):
        """
        A function that returns a png rendered by an external latex
        distribution, falling back to matplotlib rendering
        """
        if _can_print_latex(o):
            s = latex(o, mode=latex_mode, **settings)
            try:
                return _preview_wrapper(s)
            except RuntimeError as e:
                debug('preview failed with:', repr(e),
                      ' Falling back to matplotlib backend')
                if latex_mode != 'inline':
                    s = latex(o, mode='inline', **settings)
                return _matplotlib_wrapper(s)

    def _print_latex_matplotlib(o):
        """
        A function that returns a png rendered by mathtext
        """
        if _can_print_latex(o):
            s = latex(o, mode='inline', **settings)
            return _matplotlib_wrapper(s)

    def _print_latex_text(o):
        """
        A function to generate the latex representation of sympy expressions.
        """
        if _can_print_latex(o):
            s = latex(o, mode='plain', **settings)
            s = s.replace(r'\dag', r'\dagger')
            s = s.strip('$')
            return '$$%s$$' % s

    def _result_display(self, arg):
        """IPython's pretty-printer display hook, for use in IPython 0.10

           This function was adapted from:

            ipython/IPython/hooks.py:155

        """
        if self.rc.pprint:
            out = stringify_func(arg)

            if '\n' in out:
                print

            print(out)
        else:
            print(repr(arg))

    import IPython
    if V(IPython.__version__) >= '0.11':
        from sympy.core.basic import Basic
        from sympy.matrices.matrices import MatrixBase
        from sympy.physics.vector import Vector, Dyadic
        from sympy.tensor.array import NDimArray

        printable_types = [Basic, MatrixBase, float, tuple, list, set,
                frozenset, dict, Vector, Dyadic, NDimArray] + list(integer_types)

        plaintext_formatter = ip.display_formatter.formatters['text/plain']

        for cls in printable_types:
            plaintext_formatter.for_type(cls, _print_plain)

        png_formatter = ip.display_formatter.formatters['image/png']
        if use_latex in (True, 'png'):
            debug("init_printing: using png formatter")
            for cls in printable_types:
                png_formatter.for_type(cls, _print_latex_png)
        elif use_latex == 'matplotlib':
            debug("init_printing: using matplotlib formatter")
            for cls in printable_types:
                png_formatter.for_type(cls, _print_latex_matplotlib)
        else:
            debug("init_printing: not using any png formatter")
            for cls in printable_types:
                # Better way to set this, but currently does not work in IPython
                #png_formatter.for_type(cls, None)
                if cls in png_formatter.type_printers:
                    png_formatter.type_printers.pop(cls)

        latex_formatter = ip.display_formatter.formatters['text/latex']
        if use_latex in (True, 'mathjax'):
            debug("init_printing: using mathjax formatter")
            for cls in printable_types:
                latex_formatter.for_type(cls, _print_latex_text)
        else:
            debug("init_printing: not using text/latex formatter")
            for cls in printable_types:
                # Better way to set this, but currently does not work in IPython
                #latex_formatter.for_type(cls, None)
                if cls in latex_formatter.type_printers:
                    latex_formatter.type_printers.pop(cls)

    else:
        ip.set_hook('result_display', _result_display)

def _is_ipython(shell):
    """Is a shell instance an IPython shell?"""
    # shortcut, so we don't import IPython if we don't have to
    if 'IPython' not in sys.modules:
        return False
    try:
        from IPython.core.interactiveshell import InteractiveShell
    except ImportError:
        # IPython < 0.11
        try:
            from IPython.iplib import InteractiveShell
        except ImportError:
            # Reaching this points means IPython has changed in a backward-incompatible way
            # that we don't know about. Warn?
            return False
    return isinstance(shell, InteractiveShell)


[docs]def init_printing(pretty_print=True, order=None, use_unicode=None, use_latex=None, wrap_line=None, num_columns=None, no_global=False, ip=None, euler=False, forecolor='Black', backcolor='Transparent', fontsize='10pt', latex_mode='equation*', print_builtin=True, str_printer=None, pretty_printer=None, latex_printer=None, **settings): r""" Initializes pretty-printer depending on the environment. Parameters ========== pretty_print: boolean If True, use pretty_print to stringify or the provided pretty printer; if False, use sstrrepr to stringify or the provided string printer. order: string or None There are a few different settings for this parameter: lex (default), which is lexographic order; grlex, which is graded lexographic order; grevlex, which is reversed graded lexographic order; old, which is used for compatibility reasons and for long expressions; None, which sets it to lex. use_unicode: boolean or None If True, use unicode characters; if False, do not use unicode characters. use_latex: string, boolean, or None If True, use default latex rendering in GUI interfaces (png and mathjax); if False, do not use latex rendering; if 'png', enable latex rendering with an external latex compiler, falling back to matplotlib if external compilation fails; if 'matplotlib', enable latex rendering with matplotlib; if 'mathjax', enable latex text generation, for example MathJax rendering in IPython notebook or text rendering in LaTeX documents wrap_line: boolean If True, lines will wrap at the end; if False, they will not wrap but continue as one line. This is only relevant if `pretty_print` is True. num_columns: int or None If int, number of columns before wrapping is set to num_columns; if None, number of columns before wrapping is set to terminal width. This is only relevant if `pretty_print` is True. no_global: boolean If True, the settings become system wide; if False, use just for this console/session. ip: An interactive console This can either be an instance of IPython, or a class that derives from code.InteractiveConsole. euler: boolean, optional, default=False Loads the euler package in the LaTeX preamble for handwritten style fonts (http://www.ctan.org/pkg/euler). forecolor: string, optional, default='Black' DVI setting for foreground color. backcolor: string, optional, default='Transparent' DVI setting for background color. fontsize: string, optional, default='10pt' A font size to pass to the LaTeX documentclass function in the preamble. latex_mode: string, optional, default='equation*' The mode used in the LaTeX printer. Can be one of: {'inline'|'plain'|'equation'|'equation*'}. print_builtin: boolean, optional, default=True If true then floats and integers will be printed. If false the printer will only print SymPy types. str_printer: function, optional, default=None A custom string printer function. This should mimic sympy.printing.sstrrepr(). pretty_printer: function, optional, default=None A custom pretty printer. This should mimic sympy.printing.pretty(). latex_printer: function, optional, default=None A custom LaTeX printer. This should mimic sympy.printing.latex(). Examples ======== >>> from sympy.interactive import init_printing >>> from sympy import Symbol, sqrt >>> from sympy.abc import x, y >>> sqrt(5) sqrt(5) >>> init_printing(pretty_print=True) # doctest: +SKIP >>> sqrt(5) # doctest: +SKIP ___ \/ 5 >>> theta = Symbol('theta') # doctest: +SKIP >>> init_printing(use_unicode=True) # doctest: +SKIP >>> theta # doctest: +SKIP \u03b8 >>> init_printing(use_unicode=False) # doctest: +SKIP >>> theta # doctest: +SKIP theta >>> init_printing(order='lex') # doctest: +SKIP >>> str(y + x + y**2 + x**2) # doctest: +SKIP x**2 + x + y**2 + y >>> init_printing(order='grlex') # doctest: +SKIP >>> str(y + x + y**2 + x**2) # doctest: +SKIP x**2 + x + y**2 + y >>> init_printing(order='grevlex') # doctest: +SKIP >>> str(y * x**2 + x * y**2) # doctest: +SKIP x**2*y + x*y**2 >>> init_printing(order='old') # doctest: +SKIP >>> str(x**2 + y**2 + x + y) # doctest: +SKIP x**2 + x + y**2 + y >>> init_printing(num_columns=10) # doctest: +SKIP >>> x**2 + x + y**2 + y # doctest: +SKIP x + y + x**2 + y**2 """ import sys from sympy.printing.printer import Printer if pretty_print: if pretty_printer is not None: stringify_func = pretty_printer else: from sympy.printing import pretty as stringify_func else: if str_printer is not None: stringify_func = str_printer else: from sympy.printing import sstrrepr as stringify_func # Even if ip is not passed, double check that not in IPython shell in_ipython = False if ip is None: try: ip = get_ipython() except NameError: pass else: in_ipython = (ip is not None) if ip and not in_ipython: in_ipython = _is_ipython(ip) if in_ipython and pretty_print: try: import IPython # IPython 1.0 deprecates the frontend module, so we import directly # from the terminal module to prevent a deprecation message from being # shown. if V(IPython.__version__) >= '1.0': from IPython.terminal.interactiveshell import TerminalInteractiveShell else: from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell from code import InteractiveConsole except ImportError: pass else: # This will be True if we are in the qtconsole or notebook if not isinstance(ip, (InteractiveConsole, TerminalInteractiveShell)) \ and 'ipython-console' not in ''.join(sys.argv): if use_unicode is None: debug("init_printing: Setting use_unicode to True") use_unicode = True if use_latex is None: debug("init_printing: Setting use_latex to True") use_latex = True if not no_global: Printer.set_global_settings(order=order, use_unicode=use_unicode, wrap_line=wrap_line, num_columns=num_columns) else: _stringify_func = stringify_func if pretty_print: stringify_func = lambda expr: \ _stringify_func(expr, order=order, use_unicode=use_unicode, wrap_line=wrap_line, num_columns=num_columns) else: stringify_func = lambda expr: _stringify_func(expr, order=order) if in_ipython: mode_in_settings = settings.pop("mode", None) if mode_in_settings: debug("init_printing: Mode is not able to be set due to internals" "of IPython printing") _init_ipython_printing(ip, stringify_func, use_latex, euler, forecolor, backcolor, fontsize, latex_mode, print_builtin, latex_printer, **settings) else: _init_python_printing(stringify_func, **settings)