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digitalmars.D.learn - What are delimited string, heredoc and D token strings?

reply Pierre Rouleau <prouleau001 gmail.com> writes:
Hi all,

The D2.0 lexical page describes delimited string and token string 
literals.  Is there any example of how these are used and why, somewhere?

Thanks

-- Pierre
Jun 27 2010
parent reply "Simen kjaeraas" <simen.kjaras gmail.com> writes:
Pierre Rouleau <prouleau001 gmail.com> wrote:


 Hi all,

 The D2.0 lexical page describes delimited string and token string  =



 literals.  Is there any example of how these are used and why, somewhe=


re?

Token strings are added for the specific use case of string mixins[1].
They must contain valid D code.

mixin( q{ a =3D b; } ); // Works.
mixin( q{ this is nonsense, I tell you! } ); // Does not work.

Editors may syntax-highlight token strings as if it were normal code.
They often do, by virtue of having no idea that it is indeed a string.


Delimited strings and heredoc strings exist for simplicity of adding lon=
g
strings to the source.

q"EOS
Heredoc strings allow you to add long string literals to your code.
They also let you embed "quotes" 'of' `various` =C2=B4kinds=C2=B4 withou=
t escaping
them.
EOS"

q"(Delimited strings are much the same as "heredoc" strings, but somewha=
t
more succinct, by not using a whole identifier for terminators. They are=

thus not as suited for long texts.)"


[1]: http://digitalmars.com/d/2.0/statement.html#MixinStatement
      also,
      http://digitalmars.com/d/2.0/expression.html#MixinExpression
      http://digitalmars.com/d/2.0/module.html#MixinDeclaration
-- =

Simen
Jun 27 2010
next sibling parent reply Pierre Rouleau <prouleau001 gmail.com> writes:
On 27/06/10 9:52 AM, Simen kjaeraas wrote:

 Pierre Rouleau <prouleau001 gmail.com> wrote:


 Hi all,

 The D2.0 lexical page describes delimited string and token string
 literals. Is there any example of how these are used and why, somewhere?


 Token strings are added for the specific use case of string mixins[1].
 They must contain valid D code.

 mixin( q{ a = b; } ); // Works.
 mixin( q{ this is nonsense, I tell you! } ); // Does not work.

 Editors may syntax-highlight token strings as if it were normal code.
 They often do, by virtue of having no idea that it is indeed a string.


 Delimited strings and heredoc strings exist for simplicity of adding long
 strings to the source.

 q"EOS
 Heredoc strings allow you to add long string literals to your code.
 They also let you embed "quotes" 'of' `various` ´kinds´ without escaping
 them.
 EOS"

 q"(Delimited strings are much the same as "heredoc" strings, but somewhat
 more succinct, by not using a whole identifier for terminators. They are
 thus not as suited for long texts.)"


 [1]: http://digitalmars.com/d/2.0/statement.html#MixinStatement
 also,
 http://digitalmars.com/d/2.0/expression.html#MixinExpression
 http://digitalmars.com/d/2.0/module.html#MixinDeclaration


Thanks for this clear explanation, Simen.

I was wondering if D had the equivalnt of Python's triple quote string 
literals and it does: the delimited string serves the same purpose.  Great!

-- Pierre
Jun 27 2010
parent reply bearophile <bearophileHUGS lycos.com> writes:
Pierre Rouleau:

 I was wondering if D had the equivalnt of Python's triple quote string 
 literals and it does: the delimited string serves the same purpose.  Great!


But keep in mind that normal D string literals can span more than one line :-)

Bye,
bearophile
Jun 27 2010
parent reply Pierre Rouleau <prouleau001 gmail.com> writes:
On 27/06/10 11:36 AM, bearophile wrote:


 But keep in mind that normal D string literals can span more than one line :-)


In what sense? In the sense that adjacent strings are concatenated? If I 
want to create a string literal that embeds new line without explicitly 
placing a '\n' inside the string, I did not see any other way than using 
the delimited string (at least inside 
http://www.digitalmars.com/d/2.0/lex.html).  What am I missing?

-- Pierre
Jun 27 2010
parent reply bearophile <bearophileHUGS lycos.com> writes:
Pierre Rouleau:

 In what sense?


This is valid D1 code:

import std.stdio;
void main() {
  string s = "this is 
  just
a 
test";
  writefln(s);
}

Bye,
bearophile
Jun 27 2010
parent Pierre Rouleau <prouleau001 gmail.com> writes:
On 27/06/10 1:03 PM, bearophile wrote:

 Pierre Rouleau:

 In what sense?


 This is valid D1 code:

 import std.stdio;
 void main() {
    string s = "this is
    just
 a
 test";
    writefln(s);
 }

 Bye,
 bearophile


Thanks!

-- Pierre
Jun 28 2010
prev sibling parent Pierre Rouleau <prouleau001 gmail.com> writes:
On 27/06/10 9:52 AM, Simen kjaeraas wrote:

 Pierre Rouleau <prouleau001 gmail.com> wrote:


 Hi all,

 The D2.0 lexical page describes delimited string and token string
 literals. Is there any example of how these are used and why, somewhere?


 Token strings are added for the specific use case of string mixins[1].
 They must contain valid D code.

 mixin( q{ a = b; } ); // Works.
 mixin( q{ this is nonsense, I tell you! } ); // Does not work.

 Editors may syntax-highlight token strings as if it were normal code.
 They often do, by virtue of having no idea that it is indeed a string.


 Delimited strings and heredoc strings exist for simplicity of adding long
 strings to the source.

 q"EOS
 Heredoc strings allow you to add long string literals to your code.
 They also let you embed "quotes" 'of' `various` ´kinds´ without escaping
 them.
 EOS"

 q"(Delimited strings are much the same as "heredoc" strings, but somewhat
 more succinct, by not using a whole identifier for terminators. They are
 thus not as suited for long texts.)"


 [1]: http://digitalmars.com/d/2.0/statement.html#MixinStatement
 also,
 http://digitalmars.com/d/2.0/expression.html#MixinExpression
 http://digitalmars.com/d/2.0/module.html#MixinDeclaration


Thanks for this clear explanation, Simen.

I was wondering if D had the equivalent of Python's triple quote string 
literals and it does: the delimited string serves the same purpose.  Great!

-- Pierre
Jun 27 2010