CSS selectors

[amolenaar]

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Documentation content changes

What is the current behavior?

A very limited level of styling is possible. Basically only one (wildcard) rule can be created, which is applicable for all diagram items.

Issue Number: #284

What is the new behavior?

CSS can be applied on:

• item name
• item hierarchy (nesting) in the diagram

[danyeaw]

I like this, I wasn't familiar with using itemgetter as a sort key

[sourcery-ai]

Sourcery Code Quality Report (beta)

❌ Merging this PR will decrease code quality in the affected files by 0.03 out of 10.

	Before	After	Change
Quality	9.02	9.0	-0.03
Complexity	1.34	1.39	0.06
Method Length	36.84	37.39	0.55
Lines	1217	1758	541

Changed files	Quality Before	Quality After	Quality Change
gaphor/UML/classes/association.py	8.71	8.71	-0.0 ⬇️
gaphor/core/modeling/presentation.py	9.5	9.51	0.01 ⬆️
gaphor/core/styling/init.py	N/A	8.6	N/A
gaphor/core/styling/parser.py	N/A	9.0	N/A
gaphor/core/styling/selectors.py	N/A	8.83	N/A
gaphor/core/styling/tests/test_selector.py	N/A	9.07	N/A
gaphor/diagram/presentation.py	8.92	8.91	-0.01 ⬇️
gaphor/diagram/general/simpleitem.py	9.12	9.12	0.0 ⬆️
gaphor/diagram/tests/test_style.py	9.16	9.16	0.0

Here are some functions in these files that still need a tune-up:

File	Function	Quality	Recommendation
gaphor/UML/classes/association.py	AssociationEnd.post_update	3.72	Split out functionality
gaphor/core/styling/parser.py	parse_attribute_selector	4.22	Split out functionality
gaphor/core/styling/parser.py	parse_qualified_name	4.54	Split out functionality
gaphor/core/styling/parser.py	parse_simple_selector	4.62	Split out functionality
gaphor/UML/classes/association.py	AssociationItem.post_update	4.72	Split out functionality

Please see our documentation here for details on how these metrics are calculated.

We are actively working on this report - lots more documentation and extra metrics to come!

Let us know what you think of it via email or our Gitter!

[danyeaw]

Very nice - really impressive you got this to work. 🎉 I didn't know anything about CSS selectors or specificity before reviewing this PR, but now I know just a little bit.

[amolenaar]

With two bits of help from the cssselect2 code 😃 .