Richard Suchenwirth 2002-11-14 - A reference is something that points to another something (if you pardon the scientific expression). In C, references are done with pointers; in Tcl, references are strings (everything is a string), namely names of variables, which via a hashtable can be resolved (dereferenced) to the "other something" they point to:
puts foo ;# just the string foo puts $foo ;# dereference variable with name of foo puts [set foo] ;# the same
This can done more than one time with nested set commands. Compare the following C and Tcl programs, that do the same (trivial) job, and exhibit remarkable similarity:
#include <stdio.h>
int main(void) {
int i = 42;
int *ip = &i;
int **ipp = &ip;
int ***ippp = &ipp;
printf("hello, %d\n", ***ippp);
return 0;
}...and Tcl:
set i 42 set ip i set ipp ip set ippp ipp puts "hello, [set [set [set ipp]]]"
The C asterisks correlate to set calls in derefencing, while in Tcl similar markup is not needed in declaring.