109 lines
4.0 KiB
Markdown
109 lines
4.0 KiB
Markdown
# Pantograph
|
|
|
|
An interaction system for Lean 4.
|
|
|
|
|
|
|
|
## Installation
|
|
|
|
Install `elan` and `lean4`. Then, execute
|
|
``` sh
|
|
lake build
|
|
```
|
|
Then, setup the `LEAN_PATH` environment variable so it contains the library path of lean libraries. The libraries must be built in advance. For example, if `mathlib4` is stored at `../lib/mathlib4`,
|
|
``` sh
|
|
LIB="../lib"
|
|
LIB_MATHLIB="$LIB/mathlib4/lake-packages"
|
|
export LEAN_PATH="$LIB/mathlib4/build/lib:$LIB_MATHLIB/aesop/build/lib:$LIB_MATHLIB/Qq/build/lib:$LIB_MATHLIB/std/build/lib"
|
|
|
|
LEAN_PATH=$LEAN_PATH build/bin/pantograph $@
|
|
```
|
|
Note that `lean-toolchain` must be present in the `$PWD` in order to run Pantograph! This is because Pantograph taps into Lean's internals.
|
|
|
|
## Usage
|
|
|
|
``` sh
|
|
build/bin/pantograph MODULES|LEAN_OPTIONS
|
|
```
|
|
|
|
The REPL loop accepts commands as single-line JSON inputs and outputs either an
|
|
`Error:` (indicating malformed command) or a JSON return value indicating the
|
|
result of a command execution. The command can be passed in one of two formats
|
|
```
|
|
command { ... }
|
|
{ "cmd": command, "payload": ... }
|
|
```
|
|
The list of available commands can be found in `Pantograph/Commands.lean` and below. An
|
|
empty command aborts the REPL.
|
|
|
|
The `Pantograph` executable must be run with a list of modules to import. It can
|
|
also accept lean options of the form `--key=value` e.g. `--pp.raw=true`.
|
|
|
|
Example: (~5k symbols)
|
|
```
|
|
$ build/bin/Pantograph Init
|
|
lib.catalog
|
|
lib.inspect {"name": "Nat.le_add_left"}
|
|
```
|
|
Example with `mathlib4` (~90k symbols, may stack overflow, see troubleshooting)
|
|
```
|
|
$ lake env build/bin/Pantograph Mathlib.Analysis.Seminorm
|
|
lib.catalog
|
|
```
|
|
Example proving a theorem: (alternatively use `proof.start {"copyFrom": "Nat.add_comm"}`) to prime the proof
|
|
```
|
|
$ env build/bin/Pantograph Init
|
|
proof.start {"expr": "∀ (n m : Nat), n + m = m + n"}
|
|
proof.tactic {"treeId": 0, "stateId": 0, "goalId": 0, "tactic": "intro n m"}
|
|
proof.tactic {"treeId": 0, "stateId": 1, "goalId": 0, "tactic": "assumption"}
|
|
proof.printTree {"treeId": 0}
|
|
proof.tactic {"treeId": 0, "stateId": 1, "goalId": 0, "tactic": "rw [Nat.add_comm]"}
|
|
proof.printTree {"treeId": 0}
|
|
```
|
|
where the application of `assumption` should lead to a failure.
|
|
|
|
## Commands
|
|
|
|
See `Pantograph/Commands.lean` for a description of the parameters and return values in JSON.
|
|
- `reset`: Delete all cached expressions and proof trees
|
|
- `expr.echo {"expr": <expr>}`: Determine the type of an expression and round-trip it
|
|
- `lib.catalog`: Display a list of all safe Lean symbols in the current context
|
|
- `lib.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.
|
|
- `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/Commands.lean`
|
|
- `options.print`: Display the current set of options
|
|
- `proof.start {["name": <name>], ["expr": <expr>], ["copyFrom": <symbol>]}`: Start a new proof state from a given expression or symbol
|
|
- `proof.tactic {"treeId": <id>, "stateId": <id>, "goalId": <id>, "tactic": string}`: Execute a tactic on a given proof state
|
|
- `proof.printTree {"treeId": <id>}`: Print the topological structure of a proof tree
|
|
|
|
## 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.
|
|
|
|
## Troubleshooting
|
|
|
|
If lean encounters stack overflow problems when printing catalog, execute this before running lean:
|
|
```sh
|
|
ulimit -s unlimited
|
|
```
|
|
|
|
## Testing
|
|
|
|
The tests are based on `LSpec`. To run tests,
|
|
``` sh
|
|
test/all.sh
|
|
```
|