| ocGotoValues | Michelson.Optimizer |
| ocGotoValuesL | Michelson.Optimizer |
| ocRuleset | Michelson.Optimizer |
| OddNumberBytesException | Michelson.Parser.Error, Michelson.Parser |
| OneField | Michelson.Typed.Haskell.Instr.Sum, Michelson.Typed.Haskell.Instr, Michelson.Typed.Haskell, Michelson.Typed |
| onelineOption | Morley.CLI |
| oneMutez | Tezos.Core |
| OneVarAnn | Michelson.Untyped.Annotation, Michelson.Untyped |
| onFirst | Util.Type |
| onScopeCheckInstrErr | Michelson.TypeCheck.Helpers |
| onTypeCheckInstrAnnErr | Michelson.TypeCheck.Helpers |
| onTypeCheckInstrErr | Michelson.TypeCheck.Helpers |
| ooBalance | Michelson.Typed.Origination |
| ooContract | Michelson.Typed.Origination |
| ooDelegate | Michelson.Typed.Origination |
| ooOriginator | Michelson.Typed.Origination |
| ooStorage | Michelson.Typed.Origination |
| opAbsense | Michelson.Typed.Scope, Michelson.Typed |
| OpAbsent | Michelson.Typed.Scope, Michelson.Typed |
| OpCreateContract | Michelson.Typed.Value, Michelson.Typed |
| Operation | Michelson.Typed.Aliases, Michelson.Typed |
| Operation' | Michelson.Typed.Value, Michelson.Typed |
| OperationHash | |
| 1 (Type/Class) | Tezos.Address, Michelson.Untyped.Instr, Michelson.Untyped |
| 2 (Data Constructor) | Tezos.Address, Michelson.Untyped.Instr, Michelson.Untyped |
| OpPresence | Michelson.Typed.Scope, Michelson.Typed |
| OpPresent | Michelson.Typed.Scope, Michelson.Typed |
| ops | Michelson.Parser |
| ops' | Michelson.Parser.Instr |
| OpSetDelegate | Michelson.Typed.Value, Michelson.Typed |
| OpSize | |
| 1 (Type/Class) | Michelson.Untyped.OpSize, Michelson.Untyped, Michelson.Typed.OpSize, Michelson.Typed |
| 2 (Data Constructor) | Michelson.Untyped.OpSize, Michelson.Untyped, Michelson.Typed.OpSize, Michelson.Typed |
| opSizeHardLimit | Michelson.Untyped.OpSize, Michelson.Untyped, Michelson.Typed.OpSize, Michelson.Typed |
| optimize | Michelson.Optimizer |
| OptimizerConf | |
| 1 (Type/Class) | Michelson.Optimizer |
| 2 (Data Constructor) | Michelson.Optimizer |
| optimizeWithConf | Michelson.Optimizer |
| OpTransferTokens | Michelson.Typed.Value, Michelson.Typed |
| OR | |
| 1 (Data Constructor) | Michelson.Untyped.Instr, Michelson.Untyped |
| 2 (Data Constructor) | Michelson.Typed.Instr, Michelson.Typed |
| Or | Michelson.Typed.Arith, Michelson.Typed |
| orAnn | Michelson.Untyped.Annotation, Michelson.Untyped |
| orderContractBlock | Michelson.Untyped.Contract, Michelson.Untyped |
| originateContract | Michelson.Runtime |
| OriginateOp | Michelson.Runtime |
| OriginationIndex | |
| 1 (Type/Class) | Tezos.Address |
| 2 (Data Constructor) | Tezos.Address |
| OriginationOperation | |
| 1 (Type/Class) | Michelson.Typed.Origination |
| 2 (Data Constructor) | Michelson.Typed.Origination |
| orRule | Michelson.Optimizer |
| orSimpleRule | Michelson.Optimizer |
| outputOption | Util.CLI |
| Over2 | Util.Fcf |