My bad to use the name "param" for two different content, but any
ways:

First params typically assembles to this:
x1.to_s + ', ' + x2.to_s + ', ' + x3.to_s + ', ' + x4.to_s
Now I have created the code, not the string.

The line
params_2 = #{params};
extends to:
params_2 = x1.to_s + ', ' + x2.to_s + ', ' + x3.to_s + ', ' + x4.to_s
and assembles my input so that
params_2 == 'myDB, 20110101, 20110201, all'

Output from the function when STUB_CALLS=1:
Calling shop_GetFundReq(x1, x2, x3, x4) with parameters <myDB,
20110101, 20110201, all>

BR,
Andreas