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digitalmars.D - Phobos: Arbitrary delimiter variants of (std.string) stripLeft and

reply Chad J <chadjoan __spam.is.bad__gmail.com> writes:
I'm not exactly sure what the arbitrary delimiter variants of stripLeft 
and stripRight are, but they should be referenced in the documentation 
of those functions.  And if they don't exist, why don't we have them?

I was looking around for trimLeft and trimRight, but no luck.  chomp 
seems to be the arbitrary delimiter variant of trimRight, but then there 
is no chompLeft.  If we had chompLeft I'd expect chompRight to exist and 
chomp to remove both the left and right parts.

There are also no examples/unittests in the documentation on the website 
for stripLeft, stripRight, chomp, or a bunch of others.

Link for your convenience:
http://dlang.org/phobos/std_string.html#stripLeft
Jun 23 2012
next sibling parent reply Jonathan M Davis <jmdavisProg gmx.com> writes:
On Saturday, June 23, 2012 20:04:11 Chad J wrote:

 I'm not exactly sure what the arbitrary delimiter variants of stripLeft
 and stripRight are, but they should be referenced in the documentation
 of those functions.  And if they don't exist, why don't we have them?


There are no such variants. They could be added, but they don't currently 
exist.


 I was looking around for trimLeft and trimRight, but no luck.


trim and strip are the same thing. Having both would be bad design. It's 
understandable if you were looking for trim first, since a library could go 
with either name, and you probably have seen others using trim, but we chose 
strip, and we're not going to have both.


 chomp
 seems to be the arbitrary delimiter variant of trimRight, but then there
 is no chompLeft.


chompPrefix is chompLeft. And no, _neither_ is the delimiter variant of 
stripLeft or stripRight. stripRight with an arbitrary delimiter would remove 
all instances of that delimiter from the right-hand side of the array (and 
that delimiter would have to be a single character), whereas chomp takes a 
substring and removes _exactly_ that substring. The same would go for 
stripLeft and chompPrefix.


 If we had chompLeft I'd expect chompRight to exist and
 chomp to remove both the left and right parts.
 
 There are also no examples/unittests in the documentation on the website
 for stripLeft, stripRight, chomp, or a bunch of others.


They could be added.

- Jonathan M Davis
Jun 23 2012
parent Chad J <chadjoan __spam.is.bad__gmail.com> writes:
On 06/23/2012 08:25 PM, Jonathan M Davis wrote:

 On Saturday, June 23, 2012 20:04:11 Chad J wrote:

 I'm not exactly sure what the arbitrary delimiter variants of stripLeft
 and stripRight are, but they should be referenced in the documentation
 of those functions.  And if they don't exist, why don't we have them?


 There are no such variants. They could be added, but they don't currently
 exist.


 I was looking around for trimLeft and trimRight, but no luck.


 trim and strip are the same thing. Having both would be bad design. It's
 understandable if you were looking for trim first, since a library could go
 with either name, and you probably have seen others using trim, but we chose
 strip, and we're not going to have both.


I've seen them used to differentiate between whitespace and 
any-delimiter variants in other places, and the vocabulary seems to be 
used entirely inconsistently.  I just kind of run under the assumption 
that trim|strip mean remove /something/ from the right|left side of a 
given string.  The /something/ may or may not be whitespace or some 
delimiter of your choosing depending on what language you are in.

So yeah, I'm all for using something besides "trim". ;)


 chomp
 seems to be the arbitrary delimiter variant of trimRight, but then there
 is no chompLeft.


 chompPrefix is chompLeft. And no, _neither_ is the delimiter variant of
 stripLeft or stripRight. stripRight with an arbitrary delimiter would remove
 all instances of that delimiter from the right-hand side of the array (and
 that delimiter would have to be a single character), whereas chomp takes a
 substring and removes _exactly_ that substring. The same would go for
 stripLeft and chompPrefix.


Ah.  Looks like a doc rewrite may be in order (and add unittests/examples!):

Returns s sans the trailing delimiter, if any. If no delimiter is given, 
then any trailing '\r', '\n', "\r\n", std.uni.lineSep, or 
std.uni.paraSeps are removed.

My parse of this: "any trailing ...s are removed."

I took the plural to mean that more than one newline/separator may be 
removed.

It should parse like this: "one trailing ... is removed."


 If we had chompLeft I'd expect chompRight to exist and
 chomp to remove both the left and right parts.

 There are also no examples/unittests in the documentation on the website
 for stripLeft, stripRight, chomp, or a bunch of others.


 They could be added.

 - Jonathan M Davis


I would say "should be added" myself, given how bread-and-butter this 
stuff is for me (at least at work).  I had to write all of those myself 
when I started using this Synergy/DE|DBL language at work, and it would 
be just silly to have to do that in a powerful language like D.

I'd add all of this stuff myself except that 
http://forum.dlang.org/thread/js5nl8$h94$1 digitalmars.com
Jun 23 2012
prev sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
On Saturday, June 23, 2012 20:04:11 Chad J wrote:

 I'm not exactly sure what the arbitrary delimiter variants of stripLeft
 and stripRight are, but they should be referenced in the documentation
 of those functions.  And if they don't exist, why don't we have them?


You know, you can use find for the same thing quite easily (heck, you can use 
find instead of the current version of strip quite easily), so I'm not sure 
that this buys us much. It is a bit ugly to deal with stripRight that way, but 
if anything, I think that's an argument for adding rfind rather than an 
overload for strip.

auto strippedLeft = find!"a != b"(str, delim);
auto strippedRight = retro(find!"a != b"(retro(str), delim));
auto stripped = find!"a != b"(retro(find!"a != b"(retro(str), delim), delim);

If we had rfind, it could be

auto stripped = find!"a != b"(rfind!"a != b"(str, delim), delim);

Stripping whitespace is done often enough that strip, stripLeft, and 
stripRight are is merited, but I'm not convinced that stripping anything other 
than whitespace is common enough to merit it.

- Jonathan M Davis
Jun 26 2012