• "Chris Lajoie" <ctlajoie hotmail.com> Mar 12 2004
• Andy Friesen <andy ikagames.com> Mar 12 2004
• "Chris Lajoie" <ctlajoie hotmail.com> Mar 13 2004
• Andy Friesen <andy ikagames.com> Mar 13 2004
• Piotr Fusik <Piotr_member pathlink.com> Mar 13 2004
• "C. Sauls" <ibisbasenji yahoo.com> Mar 13 2004

"Chris Lajoie" <ctlajoie hotmail.com> writes:

Hi,
There's a feature in C# that allows one to create a verbatim string in which
escape characters have no effect, and strings can span multiple lines.  The
reason I want this is because regular expressions that have backslashes in
them must be converted so they use a double backslash instead.  This also
means that regular expressions can be copied directly out of a D file
without modification.  This isn't a big deal for regexps that have two or
three backslash characters, but the kind of regular expressions I often work
with are 100 characters or more (22 backslash chars in one I just looked
at).  The spanning multiple lines I don't use, and may not be a good idea,
but IMO, verbatim strings were an awesome idea for C# and I'd like to see
them in D as well.

here's some examples straight from the C# specification:
---------------------
string a = "hello, world";                  // hello, world
string b =  "hello, world";               // hello, world
string c = "hello \t world";               // hello     world
string d =  "hello \t world";               // hello \t world
string e = "Joe said \"Hello\" to me";      // Joe said "Hello" to me
string f =  "Joe said ""Hello"" to me";   // Joe said "Hello" to me
string g = "\\\\server\\share\\file.txt";   // \\server\share\file.txt
string h =  "\\server\share\file.txt";      // \\server\share\file.txt
string i = "one\ntwo\nthree";
string j =  "one
two
three";
---------------------

Can anyone think of any disadvantages to verbatim strings?  The ' ' char is
also wide and unmistakable; not to mention it isn't being used (afaik) for
anything else in D. Also, what are your thoughts on the line spanning?
Personally, I think it could get confusing.

This seems like it would be a fairly simple thing to impliment in the
compiler, although I am not familiar with the structure of the compiler so I
could be wrong.

Chris

Andy Friesen <andy ikagames.com> writes:

Chris Lajoie wrote:

 Hi,
 There's a feature in C# that allows one to create a verbatim string in which
 escape characters have no effect, and strings can span multiple lines.  The
 reason I want this is because regular expressions that have backslashes in
 them must be converted so they use a double backslash instead.  This also
 means that regular expressions can be copied directly out of a D file
 without modification.  This isn't a big deal for regexps that have two or
 three backslash characters, but the kind of regular expressions I often work
 with are 100 characters or more (22 backslash chars in one I just looked
 at).  The spanning multiple lines I don't use, and may not be a good idea,
 but IMO, verbatim strings were an awesome idea for C# and I'd like to see
 them in D as well.


There are two ways to do this in D.  One is r"This string is verbatim", 
the other is using backquotes: `Look at me!`

All D string literals can span lines, I believe.

  -- andy

"Chris Lajoie" <ctlajoie hotmail.com> writes:

 Hi,
 There's a feature in C# that allows one to create a verbatim string in




 escape characters have no effect, and strings can span multiple lines.




 reason I want this is because regular expressions that have backslashes




 them must be converted so they use a double backslash instead.  This




 means that regular expressions can be copied directly out of a D file
 without modification.  This isn't a big deal for regexps that have two




 three backslash characters, but the kind of regular expressions I often




 with are 100 characters or more (22 backslash chars in one I just looked
 at).  The spanning multiple lines I don't use, and may not be a good




 but IMO, verbatim strings were an awesome idea for C# and I'd like to




 them in D as well.


 There are two ways to do this in D.  One is r"This string is verbatim",
 the other is using backquotes: `Look at me!`

 All D string literals can span lines, I believe.


After having read the documentation I never found anything regarding
verbatim strings.  Can you point me to where they are discussed?  It's
certainly possible I missed something, I skimmed most of it.  Thanks!

Chris

Andy Friesen <andy ikagames.com> writes:

Chris Lajoie wrote:
There are two ways to do this in D.  One is r"This string is verbatim",
the other is using backquotes: `Look at me!`

All D string literals can span lines, I believe.


 
 After having read the documentation I never found anything regarding
 verbatim strings.  Can you point me to where they are discussed?  It's
 certainly possible I missed something, I skimmed most of it.  Thanks!


It's in the "Lexical" section.  Scroll to "String Literals"

-- andy

Piotr Fusik <Piotr_member pathlink.com> writes:

 verbatim strings were an awesome idea for C# and I'd like to see
them in D as well.


This is obviously not C#'s original idea. Personally I think that using the ' '
character is a bad idea and I prefer D's 'r'.

For your information, here's how Perl does it:
q/String that
spans multiple
lines and may contain embedded \ characters/

Note that you may choose one from many available delimiter characters: ', ", /,
!, *, #, |, etc. or a pair of parentheses or brackets.

If that's still not enough, you can use the so-called "here document":
<<EOF
blah blah blah
all characters are available: ' " / { }
EOF
(use any text for EOF).

Can anyone think of any disadvantages to verbatim strings?


In C#, you still have to escape the double-quote character or you can't use it
inside verbatim strings at all (I don't remember).

 The ' ' char is also wide and unmistakable; not to mention
 it isn't being used (afaik) for anything else in D.


This is a drawback. In the future it could be used for something more useful
than verbatim strings.

 Also, what are your thoughts on the line spanning?
Personally, I think it could get confusing.


It is sometimes useful, but rarely.

Well, D's r"" and `` are enough for me.

"C. Sauls" <ibisbasenji yahoo.com> writes:

Piotr Fusik wrote:
 It is sometimes useful, but rarely.


The one place I find myself using them very often is in printing 
usage/help messages.  Ie:

void usage() {
     printf(r"Usage: program [options]
	-1	Option 1
	-2	Option 2
	-N	Option N
     ");
}

-C. Sauls
-Invironz