| Language | First appeared | Developer |
|---|---|---|
| BNR Prolog | 1988 | Bell-Northern Research |
| Ciao | — | — |
| Constraint Handling Rules | 1991 | — |
| GNU Prolog | 1996 | GNU Project |
| Language | First appeared | Developer |
|---|---|---|
| BNR Prolog | 1988 | Bell-Northern Research |
| Ciao | — | — |
| Constraint Handling Rules | 1991 | — |
| GNU Prolog | 1996 | GNU Project |