Rim is written entirely in fortran 77. Of its few hundred subroutines, only 20 are `system dependent' and have to be edited or rewritten for each operating system. A list of these appears in table . The others should compile without modification. All source is upper case and has a maximum record length of 72 columns.
Common blocks and system parameters are included in subroutines
via `include' statements, having the form
<"INCLUDE '"<FILENAME>.DCK"'" & on the VAX/VMS version, and
"INCLUDE ("<FILENAME>")" & on the IBM/CMS version, and
"INCLUDE '"<filename>.d"'" & on the UNIX version.
so there is an inherent system dependency. However, include
statements always begin in column 7 and the included file
never includes another file.
Rim has a long history and was worked on by many programmers over a period of many years—there is, alas, little uniformity in style among the subroutines. There are also no variable naming conventions—except that parameters nearly always begin with `Z' and variables do not.