minruby.succ

interp.rb

require "minruby"

def mark_tail(tree, genv)
  case tree && tree[0]
  when "func_call"
    mhd = genv[tree[1]]
    if mhd == nil || mhd[0] == "user_defined"
      tree[0] = "tail"
    end
  when "stmts"
    mark_tail(tree[-1], genv)
  when "if"
    mark_tail(tree[2], genv)
    mark_tail(tree[3], genv)
  end
end

def evaluate(tree, genv, lenv)
  case tree[0]
  when "lit"
    tree[1]
  when "+"
    evaluate(tree[1], genv, lenv) + evaluate(tree[2], genv, lenv)
  when "-"
    evaluate(tree[1], genv, lenv) - evaluate(tree[2], genv, lenv)
  when "*"
    evaluate(tree[1], genv, lenv) * evaluate(tree[2], genv, lenv)
  when "/"
    evaluate(tree[1], genv, lenv) / evaluate(tree[2], genv, lenv)
  when "%"
    evaluate(tree[1], genv, lenv) % evaluate(tree[2], genv, lenv)
  when "<"
    evaluate(tree[1], genv, lenv) < evaluate(tree[2], genv, lenv)
  when "<="
    evaluate(tree[1], genv, lenv) <= evaluate(tree[2], genv, lenv)
  when "=="
    evaluate(tree[1], genv, lenv) == evaluate(tree[2], genv, lenv)
  when "!="
    evaluate(tree[1], genv, lenv) != evaluate(tree[2], genv, lenv)
  when ">="
    evaluate(tree[1], genv, lenv) >= evaluate(tree[2], genv, lenv)
  when ">"
    evaluate(tree[1], genv, lenv) > evaluate(tree[2], genv, lenv)
  when "||"
    evaluate(tree[1], genv, lenv) || evaluate(tree[2], genv, lenv)
  when "&&"
    evaluate(tree[1], genv, lenv) && evaluate(tree[2], genv, lenv)
  when "stmts"
    i = 1
    last = nil
    while tree[i]
      last = evaluate(tree[i], genv, lenv)
      i = i + 1
    end
    last
  when "var_assign"
    lenv[tree[1]] = evaluate(tree[2], genv, lenv)
  when "var_ref"
    lenv[tree[1]]
  when "if"
    if evaluate(tree[1], genv, lenv)
      evaluate(tree[2], genv, lenv)
    else
      if tree[3] 
        evaluate(tree[3], genv, lenv)
      end
    end
  when "while"
    while evaluate(tree[1], genv, lenv)
      evaluate(tree[2], genv, lenv)
    end
  when "tail"
    mhd = genv[tree[1]]
    new_lenv = {}
    params = mhd[1]
    i = 0
    while params[i]
      new_lenv[params[i]] = evaluate(tree[i + 2], genv, lenv)
      i = i + 1
    end
    genv["(jump)"] = [new_lenv, mhd[2]]
    true
  when "func_def"
    mark_tail(tree[3], genv)
    genv[tree[1]] = ["user_defined", tree[2], tree[3]]
  when "func_call" 
    mhd = genv[tree[1]]
    if mhd[0] == "builtin"
      args = []
      i = 0
      while tree[i + 2]
        args[i] = evaluate(tree[i + 2], genv, lenv)
        i = i + 1
      end
      minruby_call(mhd[1], args)
    else
      new_lenv = {}
      params = mhd[1]
      i = 0
      while params[i]
        new_lenv[params[i]] = evaluate(tree[i + 2], genv, lenv)
        i = i + 1
      end
      last = evaluate(mhd[2], genv, new_lenv)
      while genv["(jump)"]
        new_lenv = genv["(jump)"][0]
        jump = genv["(jump)"][1]
        genv["(jump)"] = nil
        last = evaluate(jump, genv, new_lenv)
      end
      last
    end
  when "ary_new"
    ary = []
    i = 0
    while tree[i + 1]
      ary[i] = evaluate(tree[i + 1], genv, lenv)
      i = i + 1
    end
    ary
  when "ary_ref"
    ary = evaluate(tree[1], genv, lenv)
    idx = evaluate(tree[2], genv, lenv)
    ary[idx]
  when "ary_assign"
    ary = evaluate(tree[1], genv, lenv)
    idx = evaluate(tree[2], genv, lenv)
    val = evaluate(tree[3], genv, lenv)
    ary[idx] = val
  when "hash_new"
    hsh = {}
    i = 0
    while tree[i + 1]
      key = evaluate(tree[i + 1], genv, lenv)
      val = evaluate(tree[i + 2], genv, lenv)
      hsh[key] = val
      i = i + 2
    end
    hsh
  end
end

str = minruby_load()
tree = minruby_parse(str)

genv = {
  "p" => ["builtin", "p"],
  "require" => ["builtin", "require"],
  "minruby_parse" => ["builtin", "minruby_parse"],
  "minruby_load" => ["builtin", "minruby_load"],
  "minruby_call" => ["builtin", "minruby_call"],
}
lenv = {}
evaluate(tree, genv, lenv)