SPIDER Programming Guidelines

File names should be <= 12 characters long.

The ar command mangles longer names.

In general each subroutine should be in its own file

The only exception is subroutines that are only called from within another subroutine in the same file, or a few support routines (such as document file handling, register handling, or file handling) that require use of F90 modules and are written in an "object oriented" manner.

Add SPIDER header to each file, except those which we do not keep copyright for.

Get header from spider.f.

Put subroutine purpose in SPIDER heading.

Put parameter listing in SPIDER heading.

Indicate which parameters are sent to routine and which are returned (modified).

No tabs. (use spaces instead)

Minimize GO TO usage.

All code must be compatible with Fortran 95.

Use all uppercase for code and comments.

Use descriptive variable names.

Do not use very short names such as "A" for a variable unless it is something like an index, etc.

Document with comments what you are doing and WHY you are coding this way.

Use lots of comments.

Nothing beyond column 72.

Do not use labels on do loops.

Use END DO instead.

Use existing support routines for reading user input.

Never use raw reads for input.

Use opfile.f for opening a SPIDER file.

Use opauxfile.f for opening a non-SPIDER file.

Use lundoc....f for document files.

Indent IF clauses, DO LOOP clauses.

Indent 3 spaces per level.

Align declarations neatly.

All operations must have a manual page.

Use run time allocation for large memory assignments and automatic arrays for smaller assignments.

Do not unnecessary permantent local arrays (using SAVE).

Do not incorporate code from other authors that is inconsistent with their licenses or inconsistent with our with our GPL license.

Proprietary code is not to be used in SPIDER!