Mel Intermediate Lisp

A simple Lisp to write low-level programs for the MelVM.

Some example programs can be seen here.

Build

With stable Rust installed: bash cargo build

Use the Nix shell environment

```bash

Reads the flake.nix/.lock files to get the specified rust version

nix develop ```

Compiling a Mil program

Provide the path to a *.mil file to compile. ``` mil examples/hellohash.mil

Alternatively

cargo run -- examples/hellohash.mil ``` By default, only the hash of the script is printed to stdout upon successful compilation.

To get the binary, tell the compiler to write it to a file. mil examples/hellohash.mil --output hh.mvm

Execution tests

The mil compiler also provides an environment for executing scripts on user-configured scenarios. In the MelVM, a script is associated with a UTXO, and executed only when a transaction attempts to spend it. Therefore, this test environment takes a json file consisting of a list of (UTXO, spender-transaction) values to execute. The json file specifically is of type [(CoinID, CoinDataHeight, Transaction)]. See the mil binary search tree configuration for an example.

To execute a script on a test tx file, bash mil bst.mil --test-txs.json

The results of each tx pair is printed. Indicating whether execution succeeded, and displaying the final state of the MelVM stack, which if Int(0) indicates that the spend is not allowed, and any other value means it is. ``` tx#0 - Successful execution.

Final stack

[Int(1)]

tx#1 - Successful execution.

Final stack

[Int(0)] ```

Debugging

To see the entire execution, one instruction at a time, and the evolution of the stack and heap, attach the --debug flag to compilation.

You can also disassemble a program after its been compiled to see its opcodes as interpreted by the MelVM. Use the --show-disassembly flag to get the disassembly on stdout.