Fix CAST expressions with dotted identifiers of more than 3 parts

[Copilot]

The parser was failing when using CAST() on dotted identifiers with more than 3 parts (e.g., some.long.json.path). This worked fine in regular SELECT expressions but failed specifically within CAST expressions.

Root Cause

The parseColumnCastExpr function was calling parseColumnExpr to parse the first argument of CAST expressions. However, parseColumnExpr doesn't use precedence-based parsing, so when parseIdentOrFunction eagerly consumed up to 3 parts of a dotted identifier (database.table.column), any remaining parts were left unparsed, causing the parser to expect "AS" or "," but find "." instead.

Solution

Changed parseColumnCastExpr to use parseExpr instead of parseColumnExpr. The parseExpr function uses precedence-based parsing which properly handles chains of dot operations via IndexOperation nodes for identifiers with 4+ parts.

Examples

Before (failing):

SELECT CAST(some.long.json.path, 'String') AS value
-- Error: line 0:26 expected AS or , but got .

After (working):

-- All of these now work correctly
SELECT CAST(column, 'String') AS single_part;
SELECT CAST(table.column, 'String') AS two_parts;
SELECT CAST(db.table.column, 'String') AS three_parts;
SELECT CAST(some.long.json.path, 'String') AS four_parts;
SELECT CAST(a.very.long.nested.json.path, 'String') AS many_parts;

Backward Compatibility

• 1-3 part identifiers continue to be parsed as Ident or ColumnIdentifier (unchanged behavior)
• 4+ part identifiers are now parsed as ColumnIdentifier for the first 3 parts + chain of IndexOperations for remaining parts
• All existing tests continue to pass

Fixes #187.

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[coveralls]

Pull Request Test Coverage Report for Build 17631696267

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 50.387%

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Totals
Change from base Build 17367436417:	0.0%
Covered Lines:	7422
Relevant Lines:	14730

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💛 - Coveralls