On a UNIX system, you can use another editor by defining the environment variable VISUAL. For example, to use the vi editor, jus execute the following BEFORE running VISTA:
setenv VISUAL viA maximum number of 2500 lines is allowed in a procedure. If you leave the editor with EXIT and your procedure contains more than 2500 lines, it is truncated and the last line is set to 'END'. Also, each line is allowed a maximum length of 80 characters. You can have longer lines by using linecontinue.html as described earlier.
You may also define procedures (with a maximum length of 2500 lines) with the editor before running VISTA, and read them into the procedure buffer with RP or execute them with CALL.