Why does OpenSCAD <http://www.openscad.org>version 2015.03echo "0" for the code fragment below? Instead of the expected "5". x=0; part="test"; if (part=="test") {x=5;} echo (x); Thanks, -- *Paul*

Because the x in {x = 5;} is a new x that masks the global one inside the braces. if (part=="test") {x=5; echo(x);} will echo 5 but I expect what you actually want is this: part="test"; x = (part=="test") ? 5 : 0; echo (x); On 31 January 2016 at 19:42, Paul F. Sehorne <paul@sehorne.org> wrote: > Why does OpenSCAD <http://www.openscad.org> version 2015.03 echo "0" for > the code fragment below? Instead of the expected "5". > > x=0; > part="test"; > if (part=="test") {x=5;} > echo (x); > > Thanks, > -- > *Paul* > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > >

On Sunday, January 31, 2016 2:54 PM, nop head <nop.head@gmail.com> wrote:

I had to swap ? 5 : 0to read? 0 : 5to make it work. On Sunday, January 31, 2016 2:54 PM, nop head <nop.head@gmail.com> wrote: Because the x in {x = 5;} is a new x that masks the global one inside the braces. if (part=="test") {x=5; echo(x);} will echo 5 but I expect what you actually want is this: part="test"; x = (part=="test") ? 5 : 0; echo (x); On 31 January 2016 at 19:42, Paul F. Sehorne <paul@sehorne.org> wrote: Why does OpenSCAD version 2015.03 echo "0" for the code fragment below? Instead of the expected "5".  x=0; part="test"; if (part=="test") {x=5;} echo (x); Thanks, -- Paul _______________________________________________ OpenSCAD mailing list Discuss@lists.openscad.org http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org _______________________________________________ OpenSCAD mailing list Discuss@lists.openscad.org http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org

If you do that it will print 0 instead of 5. The OP wanted 5. On 31 January 2016 at 19:58, fred <fred_dot_u@yahoo.com> wrote: > I had to swap > ? 5 : 0 > to read > ? 0 : 5 > to make it work. > > > On Sunday, January 31, 2016 2:54 PM, nop head <nop.head@gmail.com> wrote: > > > Because the x in {x = 5;} is a new x that masks the global one inside the > braces. > > if (part=="test") {x=5; echo(x);} > > will echo 5 but I expect what you actually want is this: > > part="test"; > x = (part=="test") ? 5 : 0; > echo (x); > > > > On 31 January 2016 at 19:42, Paul F. Sehorne <paul@sehorne.org> wrote: > > Why does OpenSCAD version 2015.03 echo "0" for the code fragment below? > Instead of the expected "5". > > x=0; > part="test"; > if (part=="test") {x=5;} > echo (x); > > Thanks, > -- > *Paul* > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > >

because OpenSCAD isn't a sequential language, it's functional. Once a variable is declared, it remains fixed at the provided value until it goes out of scope. You create a *new* x inside the braces, set it to 5, then immediately discard it. Your echo statement spits out the value of the toplevel x, which you've set to zero. OpenSCAD is *not* like C/Java/Python/whatever else you're used to. It's got its own thing going on which, once you get used to it, has its own beauty.