Michelson REPL

Clarification and motivation

Sometimes one may want to evaluate a single Michelson instruction or a small sequence of instructions against some particular stack. Currently it requires writing a contract which is more bothersome as opposed to just writing an instruction. We would like to make this process more convenient.

Acceptance criteria

A new command should be added to morley, let's call it repl. When you execute it, you can type Morley instructions (recall that Morley is a superset of Michelson) and they will be executed (or an error will be printed if current command is ill-typed, misspelled, etc.). It starts with empty stack. It should also be possible to type some meta commands, e. g. help, stack (to get current stack), etc.