Missing docstring examples in the `unparser` module

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Assessment

Difficulty
2/5
Estimated time
Half a day
Newbie friendliness
88/100
Issue type
Documentation
Clarity
Clearly specified
Activity status
Active
Tech stack
python
Domain
documentation

Research direction

Start in python/datafusion/unparser.py and read the existing Dialect and Unparser docstrings, then inspect the current SELECT 1 unparser test for setup. Add doctest-style examples showing the dialect differences, clarify the Dialect and with_pretty summaries, and run pytest with --doctest-modules. Done means all listed public functions have passing usage examples and the wording is corrected.

Written by the indexing model from the issue text.

Description

Description

AGENTS.md requires every public Python function to carry a usage example, but
none of the public functions in python/datafusion/unparser.py have one:

  • Dialect.default
  • Dialect.mysql
  • Dialect.postgres
  • Dialect.sqlite
  • Dialect.duckdb
  • Unparser.plan_to_sql
  • Unparser.with_pretty

The gap matters more here than in most modules, because the reason Dialect
exists is that different dialects render the same plan differently, and nothing
in the current documentation shows that difference. The existing test unparses
SELECT 1, which is identical across all four dialects.

Two smaller documentation problems sit in the same file:

  • the Dialect class summary reads "DataFusion data catalog."
  • with_pretty is documented as "Set the pretty flag.", which does not say
    what the flag changes.

Expected Behavior

All public functions in the module carry doctest-style usage examples,
consistent with the rest of the package and executed by pytest's
--doctest-modules.

Suggested Improvement

Add examples that unparse the same plan through each dialect so the differences
are visible, and correct the two docstrings noted above.

Dominant language
Python
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Forks
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Avg merge
1d 23h
Merged PRs (30d)
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