Using date comparison in a expression

[maverick792]

Hi,

I have to solve expressions which are a combination of string, numbers and dates. Example: a > 2 and b = "John" and date > "05-06-2010".

Is it even possible? If not, I suggest adding code where if string can be formatted as date, then date comparison should be used. Any thoughts or suggestions?

[vincentlejeune]

Hi,

The next 3.1 version will introduce date manipulation. You chould check how it work's here https://github.com/ezylang/EvalEx/blob/3.1.x/src/test/java/com/ezylang/evalex/functions/datetime/DateTimeFunctionsTest.java
The pull request is here #381

You have to use function to create date time.
For your example, you could write :
a > 2 and b = "John" and date > DT_PARSE("2010-06-05")

[maverick792]

I suppose it would be better if the underlying library can detect that expression contains date string and parse it to date. A date format can be set when we initialize expression variable. That way the library knows the date format.

At least that is the use case I have and I changed the evaluation value class to suit to my needs. Let me know if you would like to see it and give some feedback. I can raise a pull request.

[uklimaschewski]

Hi, sorry for the late answer.

as @vincentlejeune already noted, version 3.1 will have date and duration support included.
I am currently rearranging the conversion code in evaluation value, to make a better use of the expression configuration.

I think I will pick up your idea and add one or two additional configuration parameters, to allow automatic conversion of date, time and duration values from strings, so that instead of writing date > DT_PARSE("2010-06-05"), it would be possible to write date > "2010-06-05".

Though I am very busy at the moment, I hope to have that all ready in a few more weeks.