Using Variables in Variable definition - robotframework

Question

I am trying to get variables into variables but it wont work. I searched google and tried a lot of stuff but it did not wor out.
I hope this question ist not "dumb":
What am I doing wrong ?
*** Settings ***
Library SeleniumLibrary
Library OperatingSystem
*** Variable ***
${year} Get Time return year
${month} Get Time return month
${day} Get Time return day
${output} ${CURDIR}\Testing\Tests\SRV\csdb_#{year}-#{month}-#{day}.log
*** Testcases ***
Textfile should have a line saying the service is started
${errors} = Grep File ${output} Test

Answer 1

From the robot framework user's guide:
The most common source for variables are Variable tables in test case
files and resource files. Variable tables are convenient, because they
allow creating variables in the same place as the rest of the test
data, and the needed syntax is very simple. Their main disadvantages
are that values are always strings and they cannot be created
dynamically.
In order to do what you want, you'll need to define the variables in a keyword. For example:
*** Keywords ***
Get Output
${year}= Get Time year
${month}= Get Time month
${day}= Get Time day
${output}= Set variable ${CURDIR}/Testing/Tests/SRV/csdb_${year}-${month}-${day}.log
[Return] ${output}
*** Testcases ***
Textfile should have a line saying the service is started
${output}= Get Output
${errors} = Grep File ${output} Test
Note: you can fetch all three parts of the data in a single call to the keyword, like so:
${year} ${month} ${day}= Get Time year month day
It's a bit hard to read with the space-separated format, but the variable names must each be separated by two or more spaces, but "year month day" should have only one.