RosettaCodeData/Task/Strip-comments-from-a-string/Forth/strip-comments-from-a-strin...

26 lines
952 B
Forth

\ Rosetta Code Strip Comment
: LASTCHAR ( addr len -- addr len c) 2DUP + C@ ;
: COMMENT? ( char -- ? ) S" #;" ROT SCAN NIP ; \ test char for "#;"
: -LEADING ( addr len -- addr' len') BL SKIP ; \ remove leading space characters
: -COMMENT ( addr len -- addr len') \ removes # or ; comments
1-
BEGIN
LASTCHAR COMMENT? 0=
WHILE \ while not a comment char...
1- \ reduce length by 1
REPEAT
1- ; \ remove 1 more (the comment char)
: -TRAILING ( adr len -- addr len') \ remove trailing spaces
1-
BEGIN
LASTCHAR BL =
WHILE \ while lastchar = blank
1- \ reduce length by 1
REPEAT
1+ ;
: COMMENT-STRIP ( addr len -- addr 'len) -LEADING -COMMENT -TRAILING ;