Tabs are EVIL *and* STUPID, end of discussion. (Re: Tabs versus Spaces in Source Code)

[Terry Hancock]

Edward Elliott wrote:

>Dave Hansen wrote:
>  
>
>I fail to see why less 'will work' but cat 'doesn't always work'.  
>
The distinction is not in the choice of program, but in the
way it is being used...

>The net
>effect of both is the same.  Unless you're in some weird place that pipes
>aren't allowed, these should be equivalent:
>
>cat file |sed 's/\t/    /g' |less
>less -x4 file
>  
>

Nope.  To demonstrate, I will use "T" to represent tab characters
and "S" to represent spaces (I think this will be
a lot easier to read):

In a properly formatting program, with tabstops at intervals of 4:

A=
"""
SSTSTdefSspam(self,Sfoo):
STTSSSSbarS=S1/foo
TTSTreturnSbar
"""

and
B =
"""
TTdefSspam(self,Sfoo):
SSSSSSSSSSSSbarS=S1/foo
TTTreturnSbar
"""

should render exactly the same (i.e. like the following):

A=B=
"""
        def spam(self, foo):
            bar = 1/foo
            return bar
"""

However, if we have tabstop set to 8 (the usual default),
then they will render differently:

A=
"""
                def spam(self, foo):
                    bar = 1/foo
                        return bar
"""

B=
"""
                def spam(self, foo):
            bar = 1/foo
                        return bar
"""

(both are syntax errors, of course).

Presumeably, the "x" option to less will correctly handle
tabs (I didn't know about that -- thanks, BTW), but your
sed substitution doesn't "jump to the next tabstop" when
it hits a tab, it always adds a fixed number of spaces. So
it mangles the code too:

A=
"""
                   def spam(self, foo):
                     bar = 1/foo
                         return bar
"""

B=
"""
                def spam(self, foo):
            bar = 1/foo
                        return bar
"""

>Now if you're talking about the conversion altering the data's semantics,
>that's a separate issue that has nothing to do with unix utilities and
>everything to do with the file formatting.  In that case, I'll simply refer
>you to the rest of this thread for discussion.
>  
>
Now, of course, the data I provide is nasty, mean, poorly-formatted
data, abhorable by space-zealots and tab-libertines alike (;-)), but the
point is, unless you have set up your editor to syntax color spaces
and tabs differently, you won't see the difference in the original
editor.

Cheers,
Terry

-- 
Terry Hancock (hancock at AnansiSpaceworks.com)
Anansi Spaceworks http://www.AnansiSpaceworks.com