newbspec,

You should read the SpectreMDL User Guide to get more familiar with the SpectreMDL syntax.

The for, while and until are not supported.

To iterate over a variable using MDL there is a "foreach" statement.
To implement your for loop you should do the following:

foreach insig from swp( start=500, stop=800, step=100 )
{
run timedelay as theparms
}

Alternatively, you can also explicitly state the parameter values as follows:

foreach insig from { 500, 600, 700, 800 }
{
run timedelay as theparms
}

There is also a binary search and multiple variable search (optimization) capability in SpectreMDL, please
review the reference manual for more information on them.  Examples are provided.

Thanks,
sflinch