Transpiler for Swift to JavaScript

A transpiler for a subset of Swift. Transpiles to JavaScript.

Components

• Lexer
• AST Printer
• Parser
• JavaScript Code Generation
• REPL

Supports

• var, let, variables and assignments
• int literals
• classes
• functions
• operators +, -, *, /
• parenthesis and brackets (, ), {, }
• print
• optional semicolons ;
• Constructs an AST and prints it in human-readable form
• Generates JS (Javascript) code from Swift (subset)

Test Coverage

• Lexer
• Parser
• CodeGen

Other stuff

• General error recovery
• A REPL loop

Command-Line Usage

Usage: compiler <command>

Commands:
build Compile all .swift files in current directory to .js
repl Run interactive REPL
pipe Read all data from standard input
--help Show the help message

Steps to Build

1. swift build
2. swift run
3. swift test // run unit tests

To Run

./compiler repl

Additional Info

You can run commands such as:

echo "print 1 + 2 * (3 + 4);" | ./compiler pipe

which will output:

=== AST ===
PrintStmt
  BinaryExpr(plus)
    IntLiteral(1)
    BinaryExpr(star)
      IntLiteral(2)
      BinaryExpr(plus)
        IntLiteral(3)
        IntLiteral(4)

=== Generated JS ===
console.log((1 + (2 * (3 + 4))));

cat testcode.swift | ./compiler pipe

which will output:

=== AST ===
PrintStmt
  BinaryExpr(plus)
    IntLiteral(1)
    BinaryExpr(star)
      IntLiteral(2)
      BinaryExpr(plus)
        IntLiteral(3)
        IntLiteral(4)

=== Generated JS ===
console.log((1 + (2 * (3 + 4))));