Practical IDL Programming

3 Writing IDL Programs

This chapter describes the process of defining, compiling, and running IDL programs. IDL procedures and functions are explained, as well as the manual and automatic methods that may be used to compile them. The control statements available in IDL are presented, along with examples showing how each statement may be used. Parameter and keyword arguments are covered in detail, and particular attention is paid to argument passing by reference versus value. In this chapter you will also find guidelines for checking input and output arguments in IDL programs. Include files, scripts, journaling, and global variables are described, and the chapter concludes with a description of error-handling mechanisms in IDL and tips for efficient ...