Support concatenated localizer strings

[ArturDorochowicz]

Support concatenated localizer strings (S["my " + "text"]), allowing breaking of long strings into multiple lines.

[hishamco]

Support concatenated localizer strings (S["my " + "text"]), allowing breaking of long strings into multiple lines.

Before I dig into the code, it would be better to use a multi-line string instead

var key = @"my
text";
...

var value = S[key];

[ArturDorochowicz]

Before I dig into the code, it would be better to use a multi-line string instead

var key = @"my
text";
...

var value = S[key];

But that's not the same thing, is it? This introduces a new line into the text.

[hishamco]

Yep, but why do you need to do the concatenation inside the indexer? I assume this should work normally with `IStringLocalizer ', or do you get unexpected behavior?

[ArturDorochowicz]

This is just for source code formatting - wrapping long lines so the code is more readable.

I'm rather clueless about gettext, but I think this is generally supported.

https://www.gnu.org/software/gettext/manual/html_node/Mark-Keywords.html#How-Marks-Appear-in-Sources

Note also that long strings can be split across lines, into multiple adjacent string tokens. Automatic string concatenation is performed at compile time according to ISO C and ISO C++; xgettext also supports this syntax.

https://www.gnu.org/software/gettext/manual/html_node/Long-Lines.html

Perl is smart enough to concatenate these constant string fragments into one long string at compile time, and so is xgettext.

[hishamco]

Please add more tests for a string with multiple lines (3 or more)

[hishamco]

Fix the build, then we can merge

[hishamco]

No localizer here

[ArturDorochowicz]

Yes, but this is the output

[hishamco]

Thanks a lot for your contribution