Run an inferior IDL, with I/O through buffer `(idlwave-shell-buffer)'.
If buffer exists but shell process is not running, start new IDL.
If buffer exists and shell process is running, just switch to the buffer.
When called with a prefix ARG, or when `idlwave-shell-use-dedicated-frame'
is non-nil, the shell buffer and the source buffers will be in
The command to run comes from variable `idlwave-shell-explicit-file-name',
with options taken from `idlwave-shell-command-line-options'.
The buffer is put in `idlwave-shell-mode', providing commands for sending
input and controlling the IDL job. See help on `idlwave-shell-mode'.
See also the variable `idlwave-shell-prompt-pattern'.
(Type C-h m in the shell buffer for a list of commands.) (fn &optional ARG QUICK)