Refactor: replace some dialect_of! checks with Dialect trait methods
#2171
+138
−7
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Replace 6 `dialect_of!` macro invocations in the parser with dedicated Dialect trait methods. This improves the separation between generic parsing logic and dialect-specific behavior, making it easier for custom dialects to override behavior without modifying the parser. New trait methods added: - `supports_extract_comma_syntax()` - EXTRACT(YEAR, d) syntax - `supports_subquery_as_function_arg()` - FLATTEN(SELECT ...) without parens - `supports_create_view_comment_syntax()` - CREATE VIEW ... COMMENT = '...' - `supports_array_typedef_without_element_type()` - ARRAY without element type - `supports_parens_around_table_factor()` - FROM (mytable) extra parens - `supports_values_as_table_factor()` - FROM VALUES (1,'a') without parens This follows the guidance in the codebase: "when possible please use the new style, adding a method to the Dialect trait rather than using this macro." Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Member
Author
andygrove
changed the title
dialect_of! checks with Dialect trait methods
Contributor
andygrove
added a commit
to andygrove/datafusion-sqlparser-rs
that referenced
this pull request
Jan 23, 2026
Continues the work from apache#2171 by replacing 12 more `dialect_of!` macro usages with proper `Dialect` trait methods. This allows user-defined dialects to customize parsing behavior and makes the differences between dialects more clearly documented in the trait. New trait methods added: - `supports_select_wildcard_replace` - SELECT * REPLACE syntax - `supports_select_wildcard_ilike` - SELECT * ILIKE syntax - `supports_select_wildcard_rename` - SELECT * RENAME syntax - `supports_optimize_table` - OPTIMIZE TABLE statement - `supports_install` - INSTALL statement - `supports_detach` - DETACH statement - `supports_prewhere` - PREWHERE clause - `supports_with_fill` - WITH FILL in ORDER BY - `supports_limit_by` - LIMIT BY clause - `supports_interpolate` - INTERPOLATE clause - `supports_settings` - SETTINGS clause - `supports_select_format` - FORMAT clause in SELECT Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
3 tasks
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
This PR replaces 6
dialect_of!macro invocations in the parser with dedicatedDialecttrait methods. This improves the separation between generic parsing logic and dialect-specific behavior, making it easier for custom dialects to override behavior without modifying the parser.Motivation
The codebase currently has ~134
dialect_of!macro calls scattered throughout the parser. The dialect module documentation already recommends using trait methods instead:This PR is a proof-of-concept to gauge community interest before doing more of these refactorings.
Changes
New trait methods added to
Dialect:supports_extract_comma_syntax()EXTRACT(YEAR, d)comma syntaxsupports_subquery_as_function_arg()FLATTEN(SELECT ...)without extra parenssupports_create_view_comment_syntax()CREATE VIEW ... COMMENT = '...'supports_array_typedef_without_element_type()ARRAYtype without element specificationsupports_parens_around_table_factor()FROM (mytable)extra parenssupports_values_as_table_factor()FROM VALUES (1,'a')without parensEach method includes documentation with examples and links to dialect documentation.
Test plan
cargo fmtandcargo clippypass🤖 Generated with Claude Code