Dear all, I usually use google chrome ukr.net has its own mail editor This one is sent by firefox Also the script is attached Below there are several additional tests of the default/null values behavior both inside and outside functions. Some results looks strange. 1) With lists (i) in a script nulldata 1 list znull = null isznull = exists(znull) nznull = nelem(znull) print isznull nznull (ii) inside a function function void listtestfun (scalar x, list z[null]) isz = exists(z) nz = nelem(z) print isz nz end function listtestfun(1) We have isznull = 1.0000000 nznull = 0.0000000 and isz = 1.0000000 nz = 0.0000000 as expected 2) with strings (i) in a script string snull = null issnull = exists(snull) nsnull = strlen(snull) print issnull nsnull The behavior is the same as for lists and is as expected to be Also, emptycheck = snull=="" print emptycheck We see that! 'string snull = null' actually creates the "" string (ii) inside a function function void strtestfun (scalar x, string s[null]) iss = exists(s) ns = strlen(s) print iss ns end function strtestfun(1,"oleh") OK! strtestfun(1) we have The symbol 's' is undefined *** error in function strtestfun, line 2 It seems now the problem is not with exists() but is like this: a function does not defines a string variable in contrast as it does with default null lists 3) catch string function void testfun3 (scalar x, string s[null]) catch string s err = $error print err end function testfun3(1) testfun3(1,"a") Please, explain why we have "0" in the first case and "2" in the second Oleh P.S. inserted via libre office: function void testfun2 (scalar x, int n[1::1], list z[null], string ss[null]) isn = exists(n) print isn lss = strlen(ss) print lss isz = exists(z) print isz iss = exists(ss) print iss end function nulldata 1 series z1 = 1 series z2 = 2 list zz = z1 z2 testfun2(1) testfun(1,1) testfun(1,1,z1) testfun(1,1,zz) testfun(1,1,zz,"a") string sss = null eval exists(sss) eval strlen(sss) list znull = null isznull = exists(znull) nznull = nelem(znull) print isznull nznull function void listtestfun (scalar x, list z[null]) isz = exists(z) nz = nelem(z) print isz nz end function listtestfun(1) string snull = null issnull = exists(snull) nsnull = strlen(snull) print issnull nsnull emptycheck = snull=="" print emptycheck function void strtestfun (scalar x, string s[null]) iss = exists(s) ns = strlen(s) print iss ns end function strtestfun(1) strtestfun(1,"oleh") string sss = null catch string sss err = $error print err string ssss = "a" catch string ssss err = $error print err function void testfun3 (scalar x, string s[null]) catch string s err = $error print err end function testfun3(1) testfun3(1,"a")

Dear Riccardo, Do the both variants looks better? The first one was created by hand (a very tedious way); The second one (at the bottom): gretl script->libreoffice->mail client Oleh P.S. I'd like to answer something to your new thread, but it looks too  un-detailed for me 7 грудня 2015, 12:30:38, від "Riccardo (Jack) Lucchetti" < r.lucchetti(a)univpm.it >: On Mon, 7 Dec 2015, oleg_komashko(a)ukr.net wrote: This one looks much better. Lines are very short, and it looks a bit like poetry (even more so if you read it aloud: try it), which I find quite amusing :) ------------------------------------------------------- Riccardo (Jack) Lucchetti Dipartimento di Scienze Economiche e Sociali (DiSES) Università Politecnica delle Marche (formerly known as Università di Ancona) r.lucchetti(a)univpm.it http://www2.econ.univpm.it/servizi/hpp/lucchetti ------------------------------------------------------- _______________________________________________ Gretl-devel mailing list Gretl-devel(a)lists.wfu.edu http://lists.wfu.edu/mailman/listinfo/gretl-devel