How to do programs?
To enter a short program or procedure from the keyboard, simply type .RUN.
When the final END statement is encountered, execution of the main program will
begin if no errors were found. If you entered only functions or procedures or if
the main program you entered had an error, IDL will display the IDL prompt to
show that a program is not running.
The .RNEW command compiles and saves procedures and functions in the same manner
as .RUN. In addition, all variables in the main program unit, except those in
common blocks, are erased.
test = 3.5
% PRINT: Variable is undefined: TEST.
Execution halted at:
Usually, any text editor can be used to prepare programs or procedures of
more than a few lines.
The GUI front-ends for IDL include built-in text editors, but these need not be
used if you prefer to use your own text editor or word processor. Files
containing IDL programs, procedures, and functions are assumed to have the
extension name .pro. Once the program has been entered into a file from a text
editor, run IDL and compile one or more program files using .RUN or .RNEW.