A _repr_html_ for a matchpy expression.

[tonyfast]

In the web view, a pure html representation might be better for the matchpy...Expressions

 import pprint, black, vdom, matchpy, IPython; IPython.get_ipython().display_formatter.formatters['text/html'].for_type(
        matchpy.expressions.expressions.Expression, lambda str: vdom.pre(vdom.code((black).format_str(pprint.pformat(str), 100)))._repr_html_()
    )

This snippet is meant to be registered in a notebook to demonstrate the idea.

[tonyfast]

Here is a sample view:

[pearu]

Perhaps offtopic: while looking at the repr tree of an expression is useful, it disturbs the mathematical interpretation by a human. Would it make sense to invent a less verbose representation of such a tree, for instance:

BOp
  A(shape=None)[1][0][2]
  *
  InnerProduct
    A(shape=A_shape[2])
    ...

or similar in terms of verbosity?

[saulshanabrook]

@pearu Yes that is a good idea. The __str__ version does this partially, but it doesn't do any indenting. It might be nice to have a __str__ pprint version as well as a __repr__ pprint version

[saulshanabrook]

I have this kind of pretty printing now working in jupyter notebooks: https://github.com/Quansight-Labs/uarray/blob/master/uarray/uarray/printing.py

[tonyfast]

You may prefer the IPython machinery for registering your reprs.

    def load_ipython_extension(ip):
        ip.display_formatter.formatters['text/plain'].for_type(matchpy.Operation, repr_pretty)

This would avoid some hard coding the reprs.

More info @ https://ipython.readthedocs.io/en/stable/api/generated/IPython.display.html#IPython.display.display

[saulshanabrook]

Ah nice thanks for that code snippet. Reopening this to adopt that