I mean that Lisp's composite type, tuple, always has only two elements. Lists are just syntactic sugar over tuples. This means it is pretty simple to iterate vi

I mean that Lisp's composite type, tuple, always has only two elements. Lists are just syntactic sugar over tuples. This means it is pretty simple to iterate via recursion, without special iteration-related functions -- see _evlist in the post for example. Compared to that, TCL's composite type is "list", which has an arbitrary number of elements, and recursive iteration is not as simple. Yes, one can use "lindex"/"lrange" to do LISP-style recursive iteration, but this is not idiomatic at all and has horrible performance. Instead, people use foreach/explicit numeric indices, and this needs more support and special iterating-related functions, see [0] for example. [0] https://wiki.tcl-lang.org/page/Map+in+functional+programming https://wiki.tcl-lang.org/page/Map+in+functional+programming