mame/quine-relay · error · Grass::IllegalState

no return value

Error message

no return value

What it means

Error "no return value" thrown in mame/quine-relay.

Source

Thrown at vendor/grass.rb:156

  class In < Value
    def app(m, arg)
      ch = $stdin.getc
      ret = ch ? CharFn.new(ch) : arg
      m.env.push ret
    end
  end

  private

  def eval(m)
    while true
      insn = m.code.shift
      if insn then
        insn.eval m
      else
        break if m.dump.empty?
        ret = m.env.last
        raise IllegalState, "no return value" unless ret
        m.code, m.env = m.dump.pop
        m.env.push ret
      end
    end
    raise IllegalState, "illegal final machine state" unless m.env.size == 1
    m.env.first
  end

  InitialEnv = [In.new, CharFn.new(?w.ord), Succ.new, Out.new]
  InitialDump = [[[], []], [[App.new(1, 1)], []]]

  def start(code)
    eval Machine.new(code, InitialEnv, InitialDump)
  end

  def parse(src)
    code = []
    src = src.sub(/\A[^wｗ]*/, '').gsub(/[^wｗWＷvｖ]/, '')

View on GitHub (pinned to c2aa5098d3)

When it happens

Trigger: Thrown at vendor/grass.rb:156 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of mame/quine-relay@c2aa5098d3 (2026-08-21). Data as JSON: /api/errors/b2cfbb44b21c47a2. Report an issue: GitHub.