root/hodgestar/WhitespaceCode/tabs2spaces/comment.txt

=== Embedded Programming ==

I have written a tabs to spaces converter in Whitespace [1] and embedded [2] it
into this comment. You'll need the Python interpreter from [3] because the
Haskell one doesn't report EOFs nicely.

Usage:
 python main.py file-containing-this-comment < file-with-tabs > file-with-spaces

I have included the dissambled [4] code below for your convenience. Hopefully the
blog software doesn't discard the (extremely meaningful) whitespace in this
comment!

[1] http://compsoc.dur.ac.uk/whitespace/
[2] http://compsoc.dur.ac.uk/whitespace/tools.php
[3] http://www.mrphlip.com/pywhitespace.tar.bz2
[4] http://yagni.com/whitespace/index.html

=== Source Code ===

label 1

#read a char and put copies on the stack
push 0
readchar
push 0
retrieve

#compare to EOF and jump to end if it matches
dup
push -1
sub
jz 5

#compare to \t and jump to 3 if it matches 
dup
push 9
sub
jz 3
jump 2

#non-tab
label 2
outchar
jump 4

#tab
label 3
discard
push 32
dup
dup
dup
outchar
outchar
outchar
outchar
jump 4

#goto start
label 4
jump 1

#end
label 5
exit