How to use string constants with std::map

[Regina Henschel]

Hi Stephan,

thank you for the quick answer. Generating the longer u"cd4"_ustr for 
example is no problem in XSLT. So I will likely go with that.

The hint about "not constexpr-ready" is helpful too. I have indeed 
thought about whether to use it.

Kind regards,
Regina

Stephan Bergmann schrieb am 11.10.2023 um 20:14:
> On 10/11/23 19:24, Regina Henschel wrote:
>> How to write the map? In the past it would have been something like 
>> the following:
>>
>> static const std::map<OUString, std::vector<OUString>> 
>> aConnectionSiteAngleMap{
>>      {"accentBorderCallout1",{"0","cd4","cd2","3cd4"}},
>> ...
>>      {"wedgeRoundRectCallout",{"3cd4","cd2","cd4","0","cd4"}}
>> };
>>
>> All strings are constants and neither the map nor the strings will 
>> ever change.
>>
>> How do I have to write it now?
> 
> You can keep writing it as above, or your could write it as
> 
>> static const std::map<OUString, std::vector<OUString>>
>> aConnectionSiteAngleMap{
>>      
>> {u"accentBorderCallout1"_ustr,{u"0"_ustr,u"cd4"_ustr,u"cd2"_ustr,u"3cd4"_ustr}}, 
>>
>> ...
>>      
>> {u"wedgeRoundRectCallout"_ustr,{u"3cd4"_ustr,u"cd2"_ustr,u"cd4"_ustr,u"0"_ustr,u"cd4"_ustr}} 
>>
>> };
> 
> which is a bit more efficient as it doesn't need to construct the 
> OUString instances it runtime (but it still needs to construct the 
> std::vector and std::map instances at runtime).
> 
> (You can't write it as
> 
>> static constexpr std::map<OUString, std::vector<OUString>>
>> aConnectionSiteAngleMap{
>>      
>> {u"accentBorderCallout1"_ustr,{u"0"_ustr,u"cd4"_ustr,u"cd2"_ustr,u"3cd4"_ustr}}, 
>>
>> ...
>>      
>> {u"wedgeRoundRectCallout"_ustr,{u"3cd4"_ustr,u"cd2"_ustr,u"cd4"_ustr,u"0"_ustr,u"cd4"_ustr}} 
>>
>> };
> 
> as std::map is not constexpr-ready in C++20, and neither is std::vector 
> in some standard library implementations, like in debug-mode libstdc++.)
> 
>