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> TCL's lists are multi-valued Can you elaborate? I am not sure what you mean.

• adenozine 5y ago
  Arguments are evaluated in a different order to modern lisps. It's fexprs. It's weird in tcl because you might see weird macros that are built from the inside out, which is not how they're done with lisp. Like, with syntax-case, you're replacing terms in forms, but tcl does it with upvar and uplevel, so the relation of the form (whitespace matters) and you have to manage items carefully (scoping) It sucks. Tcl will break you down. Not original commenter, btw.
• theamk 5y ago
  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