Call a function or substitute a variable value withing another variable.

[Pavel Gouchtchine]

HI All,
I am getting values for a HTTP request from a csv file.
For example value for ${payload} variable comes from the "payload" column
in the csv file.
is it possible to use a function call or another variable within payload
field value in the csv file?
is there a mechanism to evaluate all functions and variables into their
values?

Thank you, very much.
Pavel.