[Interest] initialising a dictionary-type container instance with a static table?
Shawn.Rutledge at qt.io
Mon Jan 2 13:36:10 CET 2017
> On 2 Jan 2017, at 13:02, René J.V. Bertin <rjvbertin at gmail.com> wrote:
> I must be overlooking or even forgetting something: is there a way to initialise a QMap or QHash instance with a static table, say when you're creating a fast lookup dictionary mapping enums or preprocessor tokens to a QString?
> That's information known a compile time so I was expecting to be able to avoid adding each mapping explicitly with a sequence of
> map[token] = "token";
> statements. If that's indeed possible, the documentation doesn't really showcase it.
It has operator<< and operator>> so I guess you could load it from a file.
It’s an interesting point though, if you have a fixed set of data then you could use a perfect hash and a perfect number of buckets. There’s undoubtedly some other library which can do that. I googled and found stuff like https://news.ycombinator.com/item?id=10745194 and http://stevehanov.ca/blog/index.php?id=119 which have more links to things like cmph and gperf.
But for tokenizing, maybe just use lex/flex?
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