[Python-Dev] Utopian String Interpolation

[Paul Prescod]

"M.-A. Lemburg" wrote:
> 
>...
> > Embrace the __future__!
> 
> -1.
> 
> Too dangerous. 

It isn't dangerous. That's precisely what __future__ is for! It is no
more dangerous than any other feature that uses __future__.

> ... If string interpolation makes it into the core,
> then please use a *new* construct. '\$' is currently interpreted
> as '\$' and this should not be changed (heck, just think what would
> happen to all the shell script snippets encoded in Python strings).

No, this should be changed. Completely ignoring string interpolation, I
am strongly in favour of changing the behaviour of the literal string
parser so that unknown \-combinations raise a SyntaxError. If you don't
want a backslash to be interpreted as an escape sequence start, you
should use a raw string.

The Python documentation and grammar already says:

escapeseq  ::=  "\" <any ASCII character> 

The documentation says:

"Unlike Standard  , all unrecognized escape sequences are left in the
string unchanged, i.e., the backslash is left in the string. (This
behavior is useful when debugging: if an escape sequence is mistyped,
the resulting output is more easily recognized as broken.)"

That's a weird thing to say. What could be more helpful for debugging
than a good old SyntaxError???

> BTW, why don't you wrap all this interpolation stuff into
> a module and then call a function to have it apply all the
> magic you want. 

We've been through that in this discussion already. In fact, that's how
the discussion started.

 Paul Prescod