A better implementation for 'map' #222
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mbrandonw
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stephencelis
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mbrandonw
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Nov 4, 2025
| SQLQueryExpression(transform(SQLQueryExpression(queryFragment)).queryFragment) | ||
| SQLQueryExpression( | ||
| """ | ||
| IIF(\(self), \(transform(SQLQueryExpression(queryFragment))), NULL) |
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I hoped I could use CASE/WHEN/THEN here to be SQL compatible, but apparently the cases are not lazy. They are evaluated even if their conditions are false. IIF on the other hand is lazy, and so we really can avoid invoking the transform if it is NULL.
stephencelis
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Nov 4, 2025
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Right now
maponQueryExpressionjust side steps the type checker to allow dealing with the "unwrapped" query value. This mostly works because SQLite's type system is so lax.However, if you perform a
map { … }and invoke a database function under the hood, you can accidentally feed a NULL value to something that requires non-NULL. The fix is to completely side-step invoking the transform function if the underlying value is NULL.