Posted to tcl by kbk at Wed Jan 15 12:41:01 GMT 2014view pretty
proc fib {x} { tailcall fibpart1 $x {return -level 0} } proc fibpart1 {x cont} { # evaluates $cont appending [fib $x] as a parameter if {$x <= 1} { tailcall {*}$cont 1 } else { tailcall fibpart1 [expr {$x-1}] [list fibpart2 $x $cont] } } proc fibpart2 {x cont y} { # now y is [fib {$x-1}] tailcall fibpart1 [expr {$x-2}] [list fibpart3 $y $cont] } proc fibpart3 {y cont z} { # now z is [fib {$x-2}] tailcall {*}$cont [expr {$z+$y}] } for {set i 0} {$i < 10} {incr i} { puts [fib $i] }