typelevel-interpreter

Language and working Interpreter using only TypeScript types (no JavaScript either written or emitted)

type Program<Bool extends True | False> = __<
  Set<$<"returnValue">, String<"">>,
  __<
    Set<$<"test">, Bool>,
    __<
      If<
        $<"test">,
        Set<$<"returnValue">, String<"It's true!">>,
        Set<$<"returnValue">, String<"unfortunately false :(">>
      >,
      Return<$<"returnValue">>
    >
  >
>;

const test1: RunProgram<Program<False>> = {
    result: "unfortunately false :(",
    error: {
        $signal: "return"
    }
};

const test2: RunProgram<Program<True>> = {
    result: "It's true!",
    error: {
        $signal: "return"
    }
};

Wait... WAT?

Yeah, this was a saturday project! So don't even think about production environment.

I love typelevel programming in TypeScript, so I thought... can I bring it to next level? Turned out that building a programming language and it's intepreter using only type definitions in TypeScript! :D

Supported Nodes

• [X] ReturnStatement
• [X] TrueKeyword
• [X] FalseKeyword
• [X] StringLiteral
• [X] Not
• [X] Equals
• [X] And
• [X] Expression
• [X] Block
• [X] Identifier
• [X] VariableDeclaration
• [X] ConditionalExpression