@frograming/language

This repo defines the language .frog.

Install

npm install @frograming/language

Introduction

Frogram is a simple programing language that compiles to "frogger command".

A frogger command is a String of this format: Move(Up|Right|Down|Left) | NO_OP.

This package exposes two methods: parse and interpret.

• parse takes in a frogram code, returning the abstract syntax tree (AST) of the code.
• interpret takes in the AST, returning an execuation object.

The execution object is a simple object representing the execution context:

• execution.commands
  • Type: <Array<String>>
  • Description: Commands that are returned from tick.
• execution.tick(state)
  • Type: <Function>
  • Arguments:
    • state: <Object>, an object representing the frogger state
      • A frogger state is an object with isGoalUp|isRiverUp|is(Log|Car|Wall)(Up|Right|Down|Left) keys and boolean values.
      • e.g. { isLogUp: false, isCarDown: true ... }
    • returns: <String>, a frogger command: Move(Up|Right|Down|Left) | NO_OP.
  • Description: Use the given state to run the frogCode the program until an exec statement.

Language Introduction

WIP

Usage

import { parse, interpret } '@frograming/language';

const ast = parse(`onTick {
  if (isGoalUp()) {
    exec moveUp;
  }
  if (!isCarUp()) {
    exec moveUp;
  } else {
    if (isCarLeft()) {
      exec moveRight;
    }
    if (isCarRight()) {
      exec moveLeft;
      exec moveRight;
    }
  }
}`);

const execuation = interpret(ast);

const command = execuation.tick({
  isGoalUp: true,
  isCarUp: false,
  isCarLeft: true
  ...
});

// command === 'moveUp';

Author

Jason Yu