core: (attr assembly fmt) add core directive classes (pt1)

[n-io]

Adding foundational classes for a declarative assembly format system for ParametrizedAttribute types, mirroring the implementations for op assembly format.

The existing format directives are tightly wired to operations, so this PR proposes instead to have a separate hierararchy based on AttrFormatDirective to keep the systems separate which helped keep the implementation clean. A purposefully small set of simple directives is implemented (whitespace, punctuation, keyword, param variable). Some of these overlap with implementations for op directives, so I factored out _print_whitespace, _print_punctuation, and _print_keyword. The AttrFormatProgram and AttrFormatParser resemble what is implemented for operations.

This PR is the first in a stacked series to enable full support for attribute/type assembly_format:

• core: (attr assembly fmt) add core directive classes (pt1) #5900 (this PR)
• core: (attr assembly fmt) add wiring into irdl_param_attr_def (pt2) #5901
• core: (attr assembly fmt) add optional group directive (pt3) #5902
• core: (attr assembly fmt) add qualified directive (pt4) #5903
• core: (attr assembly fmt) add params directive (pt5) #5904
• core: (attr assembly fmt) add struct directive (pt6) #5905
• core: (attr assembly fmt) add custom directive (pt7) #5906
• [WIP] core: Enable assembly_format on types and attrs #5907

[codecov]

Codecov Report

❌ Patch coverage is 76.21622% with 44 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.20%. Comparing base (d875f35) to head (377ba90).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
xdsl/irdl/declarative_assembly_format.py	73.60%	24 Missing and 9 partials ⚠️
xdsl/irdl/declarative_assembly_format_parser.py	81.66%	6 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5900      +/-   ##
==========================================
- Coverage   86.23%   86.20%   -0.03%     
==========================================
  Files         418      418              
  Lines       59893    60077     +184     
  Branches     6920     6950      +30     
==========================================
+ Hits        51649    51791     +142     
- Misses       6660     6689      +29     
- Partials     1584     1597      +13     

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[superlopuh]

No need to re-parse it, let's just get the attr def inline?

Suggested change

	def _attr_def_for(cls: type[ParametrizedAttribute]) -> ParamAttrDef:
	"""Build a ParamAttrDef from a ParametrizedAttribute class."""
	return ParamAttrDef.from_pyrdl(cls)
	def _attr_def_for(cls: type[ParametrizedAttribute]) -> ParamAttrDef:
	"""Build a ParamAttrDef from a ParametrizedAttribute class."""
	return cls.get_irdl_definition()

[superlopuh]

I can think of a simpler type :)

Suggested change

	@irdl_attr_definition
	class SimpleType(ParametrizedAttribute, TypeAttribute):
	name = "test_af.simple"
	value: IntegerType = param_def()
	@irdl_attr_definition
	class SimpleType(ParametrizedAttribute, TypeAttribute):
	name = "test_af.simple"

[superlopuh]

I would love for this part of the codebase to have 100% code coverage. Could you please take a look at what's not covered and add tests for it?

Also, I still feel like this first PR is bigger than ideal. Could you please try removing anything to do with parameters to start with? In theory we can test independently parsing punctuation and whitespace.