Shape Extruder?

[ggaliens]

What is likely wrong with my attempt to follow the pattern Optigon ?

Code:

command({shape, {manifoldlab, {shape_extruder, { _ , Shape }}}}, _St) ->          
    Cmd = {shape, {manifoldlab, {shape_extruder_next, { ignored , Shape }}}},
    io:format("AA\n", []),
    erlang:display("Shape = "),
    erlang:display(Shape),

    Qs = makeDialog("Knot1"),
    io:format("BB\n", []),
    wings_ask:dialog_preview(Cmd, true, "Extruder !", Qs, _St);
    
    
command({shape, {manifoldlab, {shape_extruder_next, { _ , Shape }}}}, _St) ->          
    make_sel_extrusion(atom_to_list(Shape), _St, dialog, true);

Gets me a crash dump like this ...

Code:

Version: 1.5.0.2012-12-15---14-17.mlab
Window: geom
Reason: function_clause

Short stack trace:
[{wings_shapes,command,2},
{wings,command_1,2},
{wings_develop,time_command,2},
{wings,raw_command,4},
{wings_wm,handle_event,3},
{wings_wm,send_event,2},
{wings_wm,do_dispatch,2},
{wings_wm,get_and_dispatch,0}]

Long stack trace:
[{wings_shapes,command,
     [{{manifoldlab,{shape_extruder_next,{ignored,'Snake'}}},
       [{{x,text},"2*(cos(T)-2 * cos(2*T))"},
        {{z,text},"2*(sin(T)+2 * sin(2*T))"},
        {{y,text},"2*(sin(3*T))"},
        {{h,text},"0.4"},
        {{red,text},"(0.95*(1-(abs(cos(T*5))))+0.2*(abs(cos(T*5))))"},
        {{green,text},"(0.95*(1-(abs(cos(T*5))))+0.60*(abs(cos(T*5))))"},
        {{blue,text},"(0.2*(1-(abs(cos(T*5))))+0.2*(abs(cos(T*5))))"},
        {{ngon,integer},"8"},
        {{sect,text},"profiles/none.cfg"},
        {{min,float},"0.500000"},
        {{max,integer},"358"},
        {{head2tail,integer},"3"},
        {{step,integer},"2"},
        {revert,false}]},
      {st,{0,nil},
          face,true,[],
          {0,nil},
          none,

---

Forget about it Optigon. I see what I did wrong !

---

OK ... followed the pattern and I thing I have hit paydirt. Seems to work.

Thank you so much for preview dialog. I will be deleting so much crappy shape extruder code that
was in lieu of a proper preview dialog. LOL.

WEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE !