On 5/2/07, Andrew Koenig <[EMAIL PROTECTED]> wrote:
Looking at PEP-3125, I see that one of the rejected alternatives is to
allow
any unfinished expression to indicate a line continuation.
I would like to suggest a modification to that alternative that has worked
successfully in another programming language, namely Stu Feldman's
EFL. EFL
is a language intended for numerical programming; it compiles into Fortran
with the interesting property that the resulting Fortran code is intended
to
be human-readable and maintainable by people who do not happen to have
access to the EFL compiler.
Anyway, the (only) continuation rule in EFL is that if the last token in a
line is one that lexically cannot be the last token in a statement, then
the
next line is considered a continuation of the current line.
Python currently has a rule that if parentheses are unbalanced, a newline
does not end the statement. If we were to translate the EFL rule to
Python,
it would be something like this:
The whitespace that follows an operator or open bracket or
parenthesis
can include newline characters.
Note that if this suggestion were implemented, it would presumably be at a
very low lexical level--even before the decision is made to turn a newline
followed by spaces into an INDENT or DEDENT token. I think that this
property solves the difficulty-of-parsing problem. Indeed, I think that
this suggestion would be easier to implement than the current
unbalanced-parentheses rule.
Would this change alter where errors are reported by the parser? Is my
x = x + # Oops.
... some other code ...
going to have an error reported 15 lines below where the actual typo was
made?
Jerry
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