Feature request: a branch that works with failing conditions without triggering an error.

[steve-h]

When using a VariableResolver with function l_if($notfoundthusnil,,) it errors as the $notfoundthusnil variable does not resolve. Sort of a javascript 'falsy' kind of problem.

What would be nice is a logical function l_notfalsy($notfoundthusnil,,) that will execute the false branch if the VariableResolver returns nil but the user is then unwise to use the $notfoundthusnil variable in the false branch.
Need a function that executes the test expression and if it is nil,0,crashes,undefined then it executes the alternate (3rd) expression.