• d-bugmail puremagic.com (64/64) Jul 22 2011 http://d.puremagic.com/issues/show_bug.cgi?id=6361
• d-bugmail puremagic.com (30/30) Jul 23 2011 http://d.puremagic.com/issues/show_bug.cgi?id=6361

d-bugmail puremagic.com writes:

http://d.puremagic.com/issues/show_bug.cgi?id=6361

           Summary: To avoid a newline in multi-line strings
           Product: D
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc


--- Comment #0 from bearophile_hugs eml.cc 2011-07-22 03:16:03 PDT ---
Multi-line strings are handy, but I have a small problem with them. This is an
example, it has a problem, there is an unwanted newline at the beginning (the
situation is the same if you use ` instead of "):

string table = "
- First item:  150
- Second item: 200
- Third item:  105";


(If you are just writing such string then you can use just write() followed by
a flush.)


To avoid it you can write this, but both break the alignment in the source
code, and they are not nice looking:

string table = "- First item:  150
- Second item: 200
- Third item:  105";


string table =
"- First item:  150
- Second item: 200
- Third item:  105";


This solution adds one ending newline instead:

    writeln(q"EOS
- First item:  150
- Second item: 200
- Third item:  105
EOS");



To solve that problem in Python you use this (in Python """ or ''' denote a
multi-line string):

table = """\
- First item:  150
- Second item: 200
- Third item:  105"""


The extra slash at the beginning avoids the start newline.

I think it's worth adding this little Python syntax detail to D too.

-------------

Note: this syntax is not meant to solve the more general problem in presence of
indentation. In this case you probably need a library solution to de-indent,
etc:

void foo()
{
    if(blah)
    {
        writeln("- First item:  150
            - Second item: 200
                -- Subitem 1
                -- Subitem 2
            - Third item:  105");
    }
}


(Thanks to Nick Sabalausky and Andrej Mitrovic for the suggestions.)

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d-bugmail puremagic.com writes:

http://d.puremagic.com/issues/show_bug.cgi?id=6361



--- Comment #1 from bearophile_hugs eml.cc 2011-07-23 09:12:53 PDT ---
Code by Andrej Mitrovic:
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=141106

It shows better why this very small change in D language is not handy to do
with a library solution:


import std.algorithm;
import std.stdio;
import std.string;

string stripNewlines(string text)
{
    auto x = text.countUntil("\n");
    auto y = text.lastIndexOf("\n");

    return text[x+1..y];
}

template EOS(string text)
{
    enum EOS = stripNewlines(text);
}

void main()
{
    writeln(EOS!"
    - First item:  150
    - Second item: 200
    - Third item:  105
    ");
}

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