Tcl/Tk in a Nutshell

Name

for

for start test next body

Implement a loop construct, similar to the for loop in C.

start	Command string, executed once at beginning
test	Expression string, for loop test
next	Command string, executed at end of each iteration
body	Command string, executed in each loop iteration

The interpreter executes start once. Then it evaluates the expression test; if the result is zero, it returns an empty string. If non-zero, it executes body, then next, and repeats the loop starting with test again.

Example

for {set i 0} {$i < 100} {incr i} {
       puts $i
   }