In the series “avoid Variants when coding in Delphi”: the comparison operator
Posted by jpluimers on 2020/08/18
For Variant types, the = comparison operator in Delphi maps to the VarCompareValue in the Variants unit.
That function fails to handle various comparisons and for some it knows it can handle raises a VarInvalidOp through various code paths (like CheckType) to VarInvalidOp because the implementation limits itself to varEmpty..varUInt64, which I think means that these are unsupported:
varRecordvarStrArgvarObjectvarUStrArgvarStringvarAnyvarUStringvarArrayvarByRef
This fails when using the = operator:
What is this code supposed to do, if
v1andv2are variant arrays with the same content?if v1 = v2 then WriteLn('equal') else WriteLn('not equal');
Spring4d has a function SameValue in the Spring.pas unit which handles more cases, at least the case when both operands are arrays having the same content.
Source: [WayBack] I think I may have mentioned that I hate Variants: What is this code supposed to do, if v1 and v2 are variant arrays with the same content? if v1 = v2… – Thomas Mueller (dummzeuch) – Google+
Thanks to Thomas Mueller and Stefan Glienke for this.
–jeroen
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