This comes up every so often on '''comp.lang.tcl''':

 Chris Nelson wrote:
 > For example, whereas I might write C like:
 > 
 >     struct s {
 >        int foo
 >        char bar
 >        float grill
 >     } 
 > 
 >     s.foo = 1;
 >     s.bar = 'c';
 >     s.grill = 3.14159;

 proc struct { name thingys } {
     foreach thing $thingys {
        uplevel set $name.$thing \[ list \]
     }
 }

 struct s {
   foo
   bar
   grill
 }

 set s.foo 1
 set s.bar c
 set s.grill 3.14159

Of course, you probably dont just want to init the "struct"
to nulls, but to reasonable values:

 proc struct { name thingys } {
     foreach { key value } $thingys {
        uplevel set $name.$key $value 
     } 
 }

 struct s {
   foo 1
   bar c
   grill 3.14159
 }

Tcl has no types, but if you want to create a typing convention
and then use types in your struct it is only a matter of adding
''type'' to the foreach that now iterates ''key'' and ''value''
over ''$thingys''. '''-PSE'''

----

So how do I create a linked list, as I would in C?

[Ro]: Well if you just want a list of objects you could just make a regular tcl list - they grow dynamically.  Each element in the list could be a reference to an object... what are you trying to represent?

[RS]: [List]s we have. The purpose of linked lists is often to allow insertion or deletion of elements, which our flat lists allow with [linsert], [lreplace] and (probably most often wanted),[lappend]. You could simulate a linked list with an array, e.g.
 set a(1,content) "hello world"
 set a(1,prev) 0 ;# "pointer" to previous
 set a(1,next) 2 ;# "pointer" to next element
... but I doubt whether that's more efficient than linsert/lreplace...