Lizzy Syntax

lizzy.txt

var ::= exp

    assign exp to var. Type of exp is set to var (type inference)

var := exp

    var an already existing variable, with a type
    set exp to var, check the type is correct statically

var :type := exp

    var a new variable of type type
    set exp to var, and check statically its type is conform

function_type ::= declare_special_type("function",
  doc "a function"
)
caller_env ::= declare_special_type("caller_env",
  doc "represents the caller's environment"
)

input_output_env ::= declare_type(
  method("doc",
    input(string_type,
          doc "documentation about the input")
  )
  method("env",
    inputs(type_type,
           doc "the environments in which the function can be executed, if not specified, caller_env")
  )
)

method_env ::= declare_type(
  method("doc",
    input(string_type,
          doc "documentation about the method")
  )
  method("input",
    doc "input"
    input(type_type,
          doc "the type accepted as an input argument")
    input(function_type,
          doc "the options to the function"
          env(input_output_env, caller_env))
  )
  method("inputs",
    doc "vararg inputs"
    input(type_type,
          doc "the type accepted as an input argument")
    input(function_type,
          doc "the options to the function"
          env(input_output_env, caller_env))
  )
  method("output",
    doc "output"
    input(type_type,
          doc "the type that is returned in this argument slot")
    input(function_type,
          doc "the options to the function"
          env(input_output_env, caller_env))
  )
  method("outputs",
    doc "vararg as outputs"
    input(type_type,
          doc "the type that is returned in these argument slot")
    input(function_type,
          doc "the options to the function"
          env(input_output_env, caller_env))
  )
  method("return",
    doc "declare the returned value, void by default"
    input(type_type,
          doc "the type that is returned")
    input(function_type,
          doc "the options to the function"
          env(input_output_env, caller_env))
  )
)

declare_type_env ::= declare_type(
  method("method",
    input(string_type,
          doc "the name of the method")
    input(function_type,
          doc "the declaration of the function"
          env(method_env, caller_env))
  )
)

env ::= declare_type(
  method("declare_type",
    input(function_type,
          env(declare_type_env, caller_env))
    return(type_type)
  )
)

function type(o)
  t = _G.getmetatable(o)
  if t then
    return t.__type(o)
  else
    return _M.none_type
  end
end