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Interpolation Expression Sequence (IES): Will Delimited Strings Ever Be Supported?
Aug 16
kdevel
Aug 16
kdevel
Aug 16
kdevel
Aug 16
kdevel
August 16
Gravatar of kdevelPosted by kdevelReply
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void main ()
{
   auto html = iq"_
<!DOCTYPE html>
<html>
   <head>
      <title>$(title)</title>
      <link rel = "stylesheet" href = "style.css">
   </head>
   <body>
_";
}

$  dmd iesdl.d
iesdl.d(3): Error: semicolon expected following auto declaration, not `"_\n<!DOCTYPE html>\n<html>\n   <head>\n      <title>$(title)</title>\n      <link rel = "`
iesdl.d(8): Error: found `stylesheet` when expecting `;` following expression
iesdl.d(3):        expression: `"_\n<!DOCTYPE html>\n<html>\n   <head>\n      <title>$(title)</title>\n      <link rel = "`
iesdl.d(8): Error: found `style` when expecting `;` following expression
iesdl.d(8):        expression: `" href = "`
iesdl.d(8): Error: found `">\n   </head>\n   <body>\n_"` when expecting `;` following expression
August 16
Gravatar of Dejan LekicPosted by Dejan Lekic
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The answer is "yes, eventually". We were close with https://github.com/dlang/DIPs/blob/master/DIPs/rejected/DIP1027.md and Adam's one which I like even more - http://dpldocs.info/this-week-in-d/Blog.Posted_2019_05_13.html , but no consensus reached...

August 16
Gravatar of Dejan LekicPosted by Dejan Lekic
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After talking to Adam on IRC, he pointed out that i`` works, so I was wrong apparently. The following works:

   string title = "D roX";
   auto html = i`
<!DOCTYPE html>
<html>
   <head>
      <title>$(title)</title>
      <link rel = "stylesheet" href = "style.css">
   </head>
   <body>
`;

iq{} does not work because what is inside is not valid D code. i"" would work if you escaped all the double-quotes which obviously you do not want to do, so i`` to the rescue!

August 16
Gravatar of kdevelPosted by kdevel
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On Friday, 16 August 2024 at 12:55:42 UTC, Dejan Lekic wrote:

>

After talking to Adam on IRC, he pointed out that i`` works, so I was wrong apparently. The following works:

   string title = "D roX";
   auto html = i`
<!DOCTYPE html>
<html>
   <head>
      <title>$(title)</title>
      <link rel = "stylesheet" href = "style.css">
   </head>
   <body>
`;

There is a \n at the beginning of the string. That is the reason for
using a delimited string [1]

   auto html = q"DELIMTER
<!DOCTYPE html>
...
DELIMITER";

[1] https://dlang.org/spec/lex.html#delimited_strings "The newline following the opening identifier is not part of the string [...]"

August 16
Gravatar of kdevelPosted by kdevel
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On Friday, 16 August 2024 at 12:55:42 UTC, Dejan Lekic wrote:

>

iq{} does not work because what is inside is not valid D code.

Valid D code is not required, valid D tokens suffice [2].

   auto html = iq{
<!DOCTYPE html>
<html>
   <head>
      <title>$(title)</title>
   </head>
   <body>
};

Works (accidentally).

[2] https://dlang.org/spec/lex.html#string_literals "Token strings open with the characters q{ and close with the token }. In between must be valid D tokens."

August 16
Gravatar of kdevelPosted by kdevel
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On Friday, 16 August 2024 at 13:49:58 UTC, kdevel wrote:
> [2] https://dlang.org/spec/lex.html#string_literals "Token strings open with the characters q{ and close with the token }. In between must be valid D tokens."

Sorry for replying to myself. But what constantly bothers me is
imprecise language in the documentation. Let me quote from the page
above:

"Token strings open with the characters q{ and close with the token }. In between must be valid D tokens."

Now from the example on that same page:

```
// q{ __EOF__ }         // error
                        // __EOF__ is not a token, it's end of file
```

__EOF__, however, /is/ a token, as we may read in [1] or [2].

[1] Issue 3695 - __EOF__ token not documented
    https://issues.dlang.org/show_bug.cgi?id=3695
    »In "D 1.x -> D 2.x migration guide" and in "lex.html", the new
     token __EOF__ introduced in the D 2 is not documented.

     I think it should be explained in the "Special Tokens" section.«

[2] Special Tokens
    https://dlang.org/spec/lex.html#specialtokens
    »__EOF__	tells the scanner to ignore everything after this token«