[Gretl-devel] Re: Incrementing using the '++' operator

Am 16.06.2019 um 16:03 schrieb Artur Tarassow: > <hansl> > scalar s = 0 > loop i=1..2 -q >      catch s = (i==1) ? 1 : +1    # no effect >      s >      catch s = (i==1) ? 1 : s++    # no effect >      s >      catch s = (i==1) ? 1 : s+1    # works as intended >      s > endloop > </hansl> > > Why is the 2nd approach not working here? Hi Artur, let's see: so the first loop iteration is basically redundant, because you have i==1 and so you repeatedly assign the number 1 to s. OK. The first assignment is also trivial, since it always assigns the number +1 (which is the same as 1 of course). So you might as well formulate the whole thing as:

<hansl> scalar s = 1 s = s++    # no effect s s = s + 1  # works as intended s </hansl> IMHO the assignment with s++ shows _some_ bug, but I'm not sure which. In hansl AFAIK s++ must be seen as a short form of the *assignment* s = s+1 (or s+=1), it is not an *expression*. And in hansl you cannot have two assignments on the same line I think. (Except in the header of a "loop for" command.) So I believe there are two possibilities: 1) s = s++ is legal, but not working, and thus a real bug. 2) [More likely I think...] The line is not really supported, and the parser should show an error message; and the fact that it doesn't do that is the bug.