Posted to tcl by kbk at Wed Jan 15 12:23:23 GMT 2014view pretty
proc fib {x} {
tailcall fibcps $x {{x} {return $x}}
}
proc fibcps {x cont} {
if {$x <= 1} {
tailcall apply $cont 1
} else {
tailcall fibcps [expr {$x-1}] \
[list [list y [list x $x] [list cont $cont]] {
tailcall fibcps [expr {$x-2}] \
[list [list z [list y $y] [list cont $cont]] {
tailcall apply $cont [expr {$y+$z}]
}]
}]
}
}
for {set i 0} {$i < 10} {incr i} {
puts [fib $i]
}
Comments
Posted by kbk at Wed Jan 15 12:39:52 GMT 2014 [text] [code]
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] }