On Sat, Mar 31, 2018 at 04:50:03PM +0200, Marius Räsener wrote:
What I have in mind is probably best described with an Example:
print(""" I am a multiline String. """)
the closing quote defines the "margin indentation" - so in this example all lines would get reduces by their leading 4 spaces, resulting in a "clean" and unintended string.
Backwards compatibility rules this out. I have many strings that intentionally include indents and you will annoy me no end if you make those indents disappear :-)
But having said that, for every one of those, I have a lot more where the indents are annoying. I either outdent the lines:
def spam(): text = """some text another line and a third one """ print(text)
or I use implicit string concatenation:
def spam(): text = ("some text\n" "another line\n" "and a third\n") print(text)
neither of which I'm really happy with.
The ideal solution would:
require only a single pair of starting/ending string delimiters;
allow string literals to be indented to the current block, for the visual look and to make it more convenient with editors which automatically indent;
evaluate without the indents;
with no runtime cost.
One solution is to add yet another string prefix, let's say d for dedent, but as Terry and others point out, that leads to a combinational explosion with f-strings and r-strings already existing.
Another possibility is to make dedent a string method:
def spam(): text = """\ some text another line and a third """.dedent() print(text)
and avoid the import of textwrap. However, that also imposes a runtime cost, which could be expensive if you are careless:
for x in seq: for y in another_seq: process("""/ some large indented string """.dedent() )
(Note: the same applies to using textwrap.dedent.)
But we could avoid that runtime cost if the keyhole optimizer performed the dedent at compile time:
triple-quoted string literal .dedent()
could be optimized at compile-time, like other constant-folding.
Out of all the options, including the status quo, the one I dislike the least is the last one:
make dedent a string method;
recommend (but don't require) that implementations perform the dedent of string literals at compile time;
(failure to do so is a quality of implementation issue, not a bug)
textwrap.dedent then becomes a thin wrapper around the string method.