You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: solid_angle.m
    path of file: ./repos/bspm/thirdparty/spm12/external/fieldtrip/private
    
    the code of the file until where you have to start completion: function [varargout] = solid_angle(varargin)

% SOLID_ANGLE of a pla
    
function
funname = mfilename('fullpath');
mexsrc  = [funname '.c'];
[mexdir, mexname] = fileparts(funname);

try
  % try to compile the mex file on the fly
  ft_warning('trying to compile MEX file from %s', mexsrc);
  cd(mexdir);

  if ispc
    mex -I. -c ../../src/geometry.c
    mex -I. -c solid_angle.c ; mex solid_angle.c solid_angle.obj geometry.obj
  else
    mex -I. -c ../../src/geometry.c
    mex -I. -c ../../src/solid_angle.c 
    mex -o solid_angle solid_angle.o geometry.o
  end