id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
31122	Clarify how the Lookup class follow the Query Expression API.	Hongtao Ma	Caio Ariede	"
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For a class to be a lookup, it must follow the Query Expression API. **Lookup and Transform naturally follow this API.**
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A Lookup is a generic class to implement lookups. A lookup is a query expression with a left-hand side, lhs; a right-hand side, rhs; and a lookup_name that is used to produce a boolean comparison between lhs and rhs such as lhs in rhs or lhs > rhs.

The notation to use a lookup in an expression is <lhs>__<lookup_name>=<rhs>.

**This class doesn’t follow the Query Expression API** since it has =<rhs> on its construction: lookups are always the end of a lookup expression.
}}}"	Cleanup/optimization	closed	Documentation	3.0	Normal	fixed		AP Jama	Ready for checkin	1	0	0	0	0	0