code: public static void glAttachShader(int programID, int shaderID)
      {
          checkContextCompatibility();
  
          JavaScriptObject program = WebGLObjectMap.get().toProgram(programID);
          JavaScriptObject shader = WebGLObjectMap.get().toShader(shaderID);
  
          nglAttachShader(program, shader);
      }
docs: <p>{@code glAttachShader} attaches the shader object specified by {@code shaderID} to the program object
  specified by {@code programID}. This indicates that shader will be included in link operations that will be
  performed on program.</p>
  
  <p>{@link #GL_INVALID_VALUE} is generated if either program or shader is not a value generated by OpenGL.</p>
  
  <p>{@link #GL_INVALID_OPERATION} is generated if program is not a program object.</p>
  
  <p>{@link #GL_INVALID_OPERATION} is generated if shader is not a shader object.</p>
  
  <p>{@link #GL_INVALID_OPERATION} is generated if shader is already attached to program.</p>
  
  @param programID Specifies the program object to which a shader object will be attached.
  @param shaderID  Specifies the shader object that is to be attached.