# REPL ## Commands See `Pantograph/Protocol.lean` for a description of the parameters and return values in JSON. * `reset`: Delete all cached expressions and proof trees * `stat`: Display resource usage * `expr.echo {"expr": <expr>, "type": <optional expected type>, ["levels": [<levels>]]}`: Determine the type of an expression and format it. * `env.catalog`: Display a list of all safe Lean symbols in the current environment * `env.inspect {"name": <name>, "value": <bool>}`: Show the type and package of a given symbol; If value flag is set, the value is printed or hidden. By default only the values of definitions are printed. * `env.save { path }`, `env.load { path }`: Save/Load the current environment to/from a file * `options.set { key: value, ... }`: Set one or more options (not Lean options; those have to be set via command line arguments.), for options, see `Pantograph/Protocol.lean` One particular option for interest for machine learning researchers is the automatic mode (flag: `"automaticMode"`). By default it is turned on, with all goals automatically resuming. This makes Pantograph act like a gym, with no resumption necessary to manage your goals. * `options.print`: Display the current set of options * `goal.start {["name": <name>], ["expr": <expr>], ["levels": [<levels>]], ["copyFrom": <symbol>]}`: Start a new proof from a given expression or symbol * `goal.tactic {"stateId": <id>, "goalId": <id>, ...}`: Execute a tactic string on a given goal. The tactic is supplied as additional key-value pairs in one of the following formats: - `{ "tactic": <tactic> }`: Execute an ordinary tactic - `{ "expr": <expr> }`: Assign the given proof term to the current goal - `{ "have": <expr>, "binderName": <name> }`: Execute `have` and creates a branch goal - `{ "calc": <expr> }`: Execute one step of a `calc` tactic. Each step must be of the form `lhs op rhs`. An `lhs` of `_` indicates that it should be set to the previous `rhs`. - `{ "conv": <bool> }`: Enter or exit conversion tactic mode. In the case of exit, the goal id is ignored. * `goal.continue {"stateId": <id>, ["branch": <id>], ["goals": <names>]}`: Execute continuation/resumption - `{ "branch": <id> }`: Continue on branch state. The current state must have no goals. - `{ "goals": <names> }`: Resume the given goals * `goal.remove {"stateIds": [<id>]}"`: Drop the goal states specified in the list * `goal.print {"stateId": <id>}"`: Print a goal state * `goal.save`{ id, path }, `env.load { path }`: Save/Load a goal state to/from a file. The environment is not carried with the state. The user is responsible to ensure the sender/receiver instances share the same environment. * `frontend.process { ["fileName": <fileName>",] ["file": <str>], invocations: <bool>, sorrys: <bool> }`: Executes the Lean frontend on a file, collecting either the tactic invocations (`"invocations": true`) or the sorrys into goal states (`"sorrys": true`) ## Errors When an error pertaining to the execution of a command happens, the returning JSON structure is ``` json { "error": "type", "desc": "description" } ``` Common error forms: * `command`: Indicates malformed command structure which results from either invalid command or a malformed JSON structure that cannot be fed to an individual command. * `index`: Indicates an invariant maintained by the output of one command and input of another is broken. For example, attempting to query a symbol not existing in the library or indexing into a non-existent proof state.