Upgraded Expression proposal

[dorantor]

I did as we discussed here #101

Also added an example how it could be with functions, so functions would be properly wrapped and less reasons to use Expression\Raw. But naming convention in Clickhouse is not same as in PSR. So Class(and file) names should differ, I think. But call Expression\Function\UuidStringToNum($uuid) is not that clear, IMO. Another option is to alter it to Expression\Function('UUIDStringToNum', $uuid). It should cover all such cases, but will be less strict and, probably, less clear.

By the way, found that I'm not a contributor here https://github.com/smi2/phpClickHouse/graphs/contributors
after #101 was merged.

Is it by design or just a merging error? Besides that I needed code from #101 into master, so I could stop using fork in my projects and switch to the main repo, having visible contributions to other projects is a nice reward and really helps in career building.

[dorantor]

BTW, Scrutinizer is complaining that

Variable "%s" not allowed in double quoted string; use sprintf() or concatenation instead

but it's the most readable way I can think of. Compare currently used

        return "UUIDStringToNum('{$this->uuid}')";

with

        return \sprintf('UUIDStringToNum(\'%s\')', $this->uuid);

or with

        return 'UUIDStringToNum(\'' . $this->uuid . '\')';