Local macro in julia

letmacro.jl

module LetMacro
export @letmacro

macro letmacro(def, block)
  sign = def.args[1]
  body = def.args[2]
  name = Symbol("@$(sign.args[1])")
  args = sign.args[2:end]
  
  newname = Symbol("@$(gensym(name))")
  
  new_block = replace_macroname(block, name, newname)
  
  eval(current_module(), :($newname($(args...)) = $(body)))
  esc(new_block)
end

function replace_macroname(ex::Expr, name, newname)
  if ex.head == :macrocall && ex.args[1] == name
    Expr(:macrocall, newname, ex.args[2:end]...)
  else
    Expr(ex.head, replace_macroname.(ex.args, name, newname)...)
  end
end

function replace_macroname(ex, name, newname)
  ex
end

end