[julia-users] main function error

[new to Julia]

Hi all: I run the following code in Julia: 

include("rec_LRd.jl")
include("constants_2D.jl")

function main(M,N)

  d_cleftvector=115e-7;

  cv_matrix=zeros(length(d_cleftvector),1);

  signal_matrix=zeros(length(d_cleftvector),1);

  num_cleft=0;
  for d_cleft=d_cleftvector
    d_cleft
    signal,cv=rec_LRd(M,N,d_cleft);
    singal_matrix[num_cleft+1]=signal;
    cv_matrix[num_cleft+1]=cv;
    num_cleft=num_cleft+1;
  end
  signal_matrix, cv_matrix
end
signal_matrix, cv_matrix=main(7,75)

There is error message coming out: UndefVarError: main not defined.

I am totally confused what happened here? Thank you very much.