Hi, Игорь! On Jun 12, Игорь Балашенко wrote:
Hello mariaDB developers! I am a participant of GSOC 2020 mentored by Nikita Malyavin and Sergey Golubchik. Currently I am working on mysqltest parser improvements and I have a question to discuss with everyone:
To be short:
Currently there are expressions in if and while to be calculated i.e
if(<expr>) code But it is written using switch and works only in condition block.
and it only supports the form of "var OP const" where OP is a comparison operator.
Code like:
let $a= 1 + 2 Makes $a = "1 + 2"
Obviously mysqltest syntax needs proper expressions thats why I decided to make them. There are following questions:
What syntax do you want to see?
let $a = 1 + 2 $a = 3 Is a bad idea because we will break lots of previous taest cases.
On the other hand, they just need to be fixed once. Old behavior is quite unexpected and confusing. I think the result will be easier to use if let will just work as one intuitively expects.
let $a = $((1 + 2)) That is done in a bash style, so it seems to be more comfortable to everyone.
Also there's an approach that MySQL took: expr $a = 1 + 2 we don't have to be compatible with MySQL on the mysqltest language, still it's an option to consider.
Another question is what operators should be in expressions? To begin with I want to implement:
+, -. *, /, ++, --, <, >, ==, !=
if/while support ==, !=, <, <=, >, >= so you have to do at least those. And then, yes, math, +, -, *, /, %. increment/decrement are less useful, may be do them later? Don't forget query_get_value(), it's an existing "function", should still be supported. I'd like to see more string functions, but let's start from simple math. Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org