Domain borders as strings / evaluate against clpfd

I have stored some clpfd things as strings in a list:

assertz(dl(["PID_A #>= 2", "PID_A #=< 4"])).

Now can I somehow evalute them against a term like A is 2?

I thought of:

dl([H1, H2 | _]), name(HH1, H1), name(HH2, H2), call((HH1, HH2, A is  
2)).
ERROR: '<meta-call>'/1: Undefined procedure: PID_A #>= 2/0


Michael