A standard game of Tic-Tac-Toe in Leo.

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Representing State

Leo allows users to define composite data types with the struct keyword. The game board is represented by a struct called Board, which contains three Rows. An alternative representation would be to use an array, however, these are not yet supported in Leo.

Language Features

• struct declarations
• conditional statements
• early termination. Leo allows users to return from a function early using the return keyword.

Running the Program

Leo provides users with a command line interface for compiling and running Leo programs. Users may either specify input values via the command line or provide an input file in inputs/.

Providing inputs via the command line.

1. Run

leo run <function_name> <input_1> <input_2> ...

See ./run.sh for an example.

Using an input file.

1. Modify inputs/tictactoe.in with the desired inputs.
2. Run

leo run <function_name>

Executing the Program

leo execute <function_name> <input_1> <input_2> ...

Playing the Game

1. Create a new game board

leo run new

| | | | |---|---|---| | 0 | 0 | 0 | | 0 | 0 | 0 | | 0 | 0 | 0 |

2. Player 1 makes a move

leo run make_move 1u8 1u8 1u8 "{ r1: { c1: 0u8, c2: 0u8, c3: 0u8 }, r2: { c1: 0u8, c2: 0u8, c3: 0u8 }, r3: { c1: 0u8, c2: 0u8, c3: 0u8 } }"

| | | | |---|---|---| | 1 | 0 | 0 | | 0 | 0 | 0 | | 0 | 0 | 0 |

3. Player 2 makes a move

leo run make_move 2u8 2u8 2u8 "{ r1: { c1: 1u8, c2: 0u8, c3: 0u8 }, r2: { c1: 0u8, c2: 0u8, c3: 0u8 }, r3: { c1: 0u8, c2: 0u8, c3: 0u8 } }"

| | | | |---|---|---| | 1 | 0 | 0 | | 0 | 2 | 0 | | 0 | 0 | 0 |