[BenSatori]

Fixes parsing of two legal Postgres SUBSTRING forms:

• SUBSTRING('hello world' FOR 5 FROM 1) (FOR before FROM)
• SUBSTRING('hello world' SIMILAR '%#"o w#"%' ESCAPE '#')

See https://www.postgresql.org/docs/current/functions-string.html

Both previously failed with a parser error. Adds a similar flag to Expr::Substring to track the SIMILAR ... ESCAPE display form, and allows FOR to be parsed before FROM (normalized to FROM ... FOR on output).

Generated with AI assistance (GitHub Copilot).

[codecov-commenter]

Codecov Report

❌ Patch coverage is 72.00000% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.09%. Comparing base (5cad906) to head (ebab908).

Files with missing lines	Patch %	Lines
src/parser/mod.rs	72.00%	0 Missing and 7 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2494      +/-   ##
==========================================
- Coverage   81.09%   81.09%   -0.01%     
==========================================
  Files          42       42              
  Lines       33684    33719      +35     
  Branches    33684    33719      +35     
==========================================
+ Hits        27316    27344      +28     
  Misses       2798     2798              
- Partials     3570     3577       +7     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[LucaCappelletti94]

Would a single syntax enum be better here, replacing special and similar with one variant each for the comma, FROM/FOR, FOR/FROM and SIMILAR/ESCAPE forms? SUBSTRING('1' FOR 3 FROM 1) now prints as SUBSTRING('1' FROM 1 FOR 3), which breaks the round trip the README promises, and a third flag for the order would leave combinations such as special with similar representable.

[LucaCappelletti94]

You may want to pin the reversed order as a round trip. On the current head it fails with left: "SELECT SUBSTRING('1' FOR 3 FROM 1)", right: "SELECT SUBSTRING('1' FROM 1 FOR 3)".

Suggested change

	one_statement_parses_to(
	"SELECT SUBSTRING('1' FOR 3 FROM 1)",
	"SELECT SUBSTRING('1' FROM 1 FOR 3)",
	);
	verified_stmt("SELECT SUBSTRING('1' FOR 3 FROM 1)");