A modest indentation proposal

Garth Grimm garth_grimm at hp.com
Fri Nov 30 01:37:41 CET 2001


I think I'd run into more problems with adding lines to the end of block, but forgetting to delete 
the ; in what used to be the last line of the block, then I do with 'forgetting' to indent blocks 
correctly.


Garth

Erann Gat wrote:

> The subject of syntactically-significant indentation seems to dominate a
> lot of discussions on Python.  Personally I've found it to be less of a
> problem than I thought it would be, but annoying nonetheless.  It also IMO
> makes the language unsuitable for mission-critical applications.  It's
> just too easy to screw up indentation (particularly when cutting and
> pasting large blocks of code) without realizing it.
> 
> I have a suggestion for how to make people like me who are uneasy with
> syntactically significant indentation feel more comfortable while at the
> same time not alienating those who thing that it's a really cool feature. 
> The proposal is based on the observation that Python already has the
> equivalent of an open-brace for code blocks.  It's the colon.  To see that
> this is so you have only to observe that a good editor can automatically
> indent code properly at the beginnings of blocks, but not at the end.  The
> solution to the problem is to add an optional end-of-block identifier.
> 
> I propose to use a semicolon at the end of a line to denote the end of a
> block, e.g.:
> 
> for i in l:        # Colon signals beginning of block
>   foo()
>   baz(); boff()    # Semicolon separating statements works as usual
>   bar();           # Semicolon at end of line signals end of block
> biff()
> 
> 
> This convention is 100% backwards-compatible with current practice, that
> is, code written using this convention runs with no problems in Python as
> it currently stands.
> 
> What I would like to see in terms of support for this convention from the
> Python community is two things:
> 
> 1) Editor support for this convention so that a semicolon at the end of a
> line causes the editor to unindent, and
> 
> 2) Parser support.  It would be enough to simply give a warning if there
> is a discrepancy between the block structure defined by indentation and
> that defined by the semicolon-at-end-of-line convention (i.e. "Warning:
> end of block detected without trailing semicolon").  Making this optional
> so that die-hard indentation fans could turn it off would also be fine.
> 
> Comments?
> 
> Erann Gat
> gat at jpl.nasa.gov
> 




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