Contitions are not well documented but it would appear that positive values or zero are false and negative values are true.

As a result
IF instr(string, "value") THEN print "found"
has the desired effect.

Equality (=), Inequality (<>)
Less Than (<), Less Than or Equal To (<=)
Greater Than (>), Greater Than or Equal To (>=)
And, Or, Xor
Eqv, Imp
IsArray, IsDate, IsEmpty, IsNull, IsNumeric, IsObject
object Is object

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