Modifying a malleable VI's output type depending on the presence of an input

[tkienzler-tt]

I would like to create a malleable VI with an optional input. If the input is not wired, the output should be a double, otherwise of the input's type. Just comparing the input to an empty variant constant won't do the trick since that's a runtime comparison, so I thought about asking a question here - which in turn made me think some more to come up with a trivial solution I thought worth sharing:

zero_or_passthrough.png

[pauldavey · Accepted solution]

That won't have the desired effect if a Variant is wired to that input.  Why don't you just make the optional input a DBL with the correct default value?

[tkienzler-tt]

Oh silly me... I somehow thought the terminals must be variants... Yeah, that makes it trivial, thanks! (For posterity's sake I got mislead by Programmatically Check If a SubVI Input Terminal Is Wired)

zero_or_passthrough.vim

[MaxJoseph]

Sorry to resurrect a dead (and solved) thread!

I want to use a .vim to modify the output type depending on the input type wired in. Several functions appear to do this, such as Scan From String, but I cannot find any documentation to adapt the output type to be the same as an input.

I tried something like tkienzler-tt had in his OP, but I cannot see that it will work as it will just coerce the type to be a variant.

[MaxJoseph]

Ah! I actually tried it and it appears that Vims naturally force all outputs linked to a given input (even indirectly!) to be the same type as the input!