let f s t = eq_carr s src && eq_carr t tgt in
let where = List.filter (fun (s,t,_) -> f s t) !db in
let rest = List.filter (fun (s,t,_) -> not (f s t)) !db in
match where with
let f s t = eq_carr s src && eq_carr t tgt in
let where = List.filter (fun (s,t,_) -> f s t) !db in
let rest = List.filter (fun (s,t,_) -> not (f s t)) !db in
match where with