CLN: create core Styler rendering functions and subclass conditional styling applications

[attack68]

Here is a first draft at splitting up style.py, ahead of adding new LaTeX functionality

Key Points

• All rendering and formatting methods moved to style_render.py:

class StylerRenderer:
    jinja2_loader
    def render()
    def format()
    def _translate()
    def _compute()

+ their module level helper functions

• style.py maintains all the conditional application methods and the utility methods and is subclass:

class Styler(StylerRenderer):
    ...

All methods copied, no changes made, other than deprivatizing shared method names.

Technically this now works:

df = pd.DataFrame([['a   b', 'c  v']])
from pandas.io.formats.style_render import StylerRenderer
StylerRenderer(df).format(str.upper).render()

[jreback]

i would make this a composite method that calls: _translate_head, _translate_body, _translate_footer, but can do in followons

[attack68]

yes is a good idea: but i'm trying hard to adopt your former advice of targeted smaller PRs! :)
(this is also why i submitted that other small PR yesterday because this is ultimately the idea)

[jreback]

that's a good idea. its totally ok to take my suggestions as followons. would rather merge things that are partial to make the workflow easier.

[jreback]

shouldn't these 2 methods be in the subclasses?

[attack68]

arguably yes. they weren't, and then I put them in last. no strong opinion, so i'll make changes.

[attack68]

you are talking about _repr_html_ and to_excel, i assume.

[jreback]

yes

[jreback]

cool I think need to rebase (do this pretty much every time when you push)

[attack68]

@jreback this is green and ready to go if you approve.

[jreback]

thanks @attack68