| L | Parsley.Internal.Common.Indexed, Parsley.Internal.Common |
| LAM_S | Parsley.Internal.Core.Defunc, Parsley.Defunctionalized, Parsley.Internal.Core, Parsley.Internal |
| Length | Parsley.Internal.Backend.InstructionAnalyser |
| Let | Parsley.Internal.Core.CombinatorAST |
| LetBinding | |
| 1 (Type/Class) | Parsley.Internal.Backend.Machine.LetBindings, Parsley.Internal.Backend.Machine |
| 2 (Data Constructor) | Parsley.Internal.Backend.Machine.LetBindings |
| letBound | Parsley.Internal.Frontend.CombinatorAnalyser |
| letRec | Parsley.Internal.Backend.Machine.LetRecBuilder |
| LET_S | Parsley.Internal.Core.Defunc, Parsley.Defunctionalized, Parsley.Internal.Core, Parsley.Internal |
| Level | |
| 1 (Type/Class) | Parsley.Precedence |
| 2 (Data Constructor) | Parsley.Precedence |
| Lift2 | Parsley.Internal.Backend.Machine.Instructions, Parsley.Internal.Backend.Machine |
| liftA2 | Parsley.Applicative, Parsley |
| liftA3 | Parsley.Applicative, Parsley |
| LIFTED | Parsley.Internal.Core.Defunc, Parsley.Defunctionalized, Parsley.Internal.Core, Parsley.Internal |
| liquidate | Parsley.Internal.Backend.Machine.State |
| local | Parsley.Register |
| LogEnter | Parsley.Internal.Backend.Machine.Instructions, Parsley.Internal.Backend.Machine |
| LogExit | Parsley.Internal.Backend.Machine.Instructions, Parsley.Internal.Backend.Machine |
| LogHandler | Parsley.Internal.Backend.Machine.Ops |
| logHandler | Parsley.Internal.Backend.Machine.Ops |
| LogOps | Parsley.Internal.Backend.Machine.InputOps |
| LookAhead | Parsley.Internal.Core.CombinatorAST |
| lookAhead | Parsley.Internal.Core.Primitives, Parsley.Internal, Parsley.Combinator, Parsley |