Structures

TclForth provides the classic Forth structures as well as useful constructs courtesy of Tcl.

###Flow Control##

####if else then#

: test { n -- }   n 0= if "is 0" else "not 0" then . ;

####case of endof default endcase#

: test { item -- }    
    item case 
       77 of "is77" endof   
       abc of "isabc" endof 
       default of "none" endof 
    endcase . ;

###Conditional Loops#

####begin again break#

: test  { n -- }  begin n incr  n .  n 10 > if break then  again  ;

####begin until#

: test  { n -- }  begin n incr  n .  n 10 > until  ;

####begin while repeat#

: test  { n -- }  begin n 10 < while  n incr  n . repeat  ;

###Counted Loops#

####do loop I J K#

0 variable sum  101 1 do  I sum add  loop  sum .

2 0 do 12 10 do 102 100 do  I . J . K . cr loop loop loop  

####leave#

0 variable sum  100 0 do  I 10 > if leave then  I sum add  loop  sum .

####times#

3 times "onemoretime" . repeat

####foreach#

Use: {data} {args} foreach ... repeat
The args are locals defined in the stack diagram.

: do-foreach  { list | x -- }  list {x} foreach x x * . repeat  ;

{11 22 33} do-foreach

For immediate use provide x as a global variable

0 variable x  {1 2 3 4} {x} foreach x 7 * . repeat

####exit = return#

: count  { start limit -- }  
  begin start .  start incr  start limit > if exit then again ;

0 99 count