A derivate of [Lisp]. A programming language with even less syntax than Tcl itself. (but special forms and the like...? [RS])

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[wdb] I strongly disagree that Scheme has less syntax than Tcl! Reason: the symbols have a value ''per se''. Tcl has no symbols as $varname is just a shortcut for [[set varname]] where ''varname'' is just a constant, and the procedure addressed by ''set'' carries all the semantics. In Tcl, the command ''list unknown'' returns ''unknown'' because it is a constant. In Scheme, ''(list unknown)'' throws an error unless a symbol ''unknown'' is defined. If you want to list an unknown symbol, indeed, you need the special form ''(quote unknown)'' resp. its shortcut '' 'unknown''. 

   * In Lisp, the special form ''quote'' is essential. 
   * In Tcl, it is not necessary as it can be defined as a regular procedure as follows:

 proc quote x {
    set x
 }

(Thank you, [RS], for the hint with the combinator ''Identity''!)

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See [Playing Scheme] | [Tcl and LISP] | [Playing LISP] | [Serial summing].

There's a [Tk]Scheme.  [[maybe more than one?]]

[wdb]: There is a Tk connection to the Scheme implementation Chicken [http://wolf-dieter-busch.de/html/Software/Tools/ChickenTk.htm].
Its successor [http://www.t3x.org/pstk/] is called '''PS/TK''' http://sourceforge.net/projects/pstk/ (maintained by Phil Bewig)
and is maintained by Nils M. Holm [http://t3x.org/nmh/].
Nils told me that PS/TK works with PLT Scheme on Win, on Scheme 48, and on Gambit.

The classic Scheme book is [SICP].





http://phaseit.net/claird/comp.lang.scheme/scheme.html
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One interesting difference is that setting of (only global?) variables and function definition both are done with ''define'', which creates a lambda if its first element is a list. Just for experimenting, here's how to have that in Tcl:
 proc define {what how} {
     if {[llength $what]==1} {
          uplevel 1 set $what [list $how]
     } else {
          proc [lindex $what 0] [lrange $what 1 end] $how
     }
 }
 % define x 42
 42
 % define {+ x y} {expr {$x+$y}}
 % + $x $x
 84
This prevents us from having spaces in variable names (not a big problem), but presents the function name and arguments in one list, similar to how it will later be called - people sometimes wonder why we define ''proc foo {x y} {..}'' but call it ''foo $x $y''...

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