Hi, here's something I don't understand. The following two lines inside a program work fine: ... value = $pi * cdf(N, finput) list lc = getFGrangerReg(X, Y, p, value) ... where of course getFGrangerReg() is a user-defined function which returns a list, and all the variables are appropriately defined. Now when I substitute out the "value" scalar as a function argument, like this: ... list lc = getFGrangerReg(X, Y, p, $pi * cdf(N, finput)) ... I get an "invalid argument" error. However, I could not build a minimal example, so in principle passing things like $pi * cdf(N, finput) as an argument does work in the trivial examples I was trying. (Notice that gretl didn't mention "getFGrangerReg" in the error message, but rather the name of the outer function in which this code resides.) So I'm puzzled... (Snapshot June 9th.) thanks, sven