arjenmarkus/old-programming-idioms

Explain old-style programming idioms used in FORTRAN 77 programs

I want to write about the typical idioms you find in old-style FORTRAN programs:

• What do they mean?
• What are modern equivalents?

This will typically be the common things from FORTRAN 77 onwards, but perhaps also a wee bit about FORTRAN 66 (like one-pass loops?)

These are the keyword/subjects I am thinking about:

• array(*) versus array(:)
• array(10) as the starting point
• COMMON blocks and BLOCK DATA, named and blank COMMON
• history of computers:
  • hardware
  • memory management
  • tools like source code control systems
  • connections between computers, Internet
• equivalence
• constants as actual arguments
• intent
• temporary arrays - non-contiguous arrays
• implicit types
• double precision versus kind
• checking interfaces
• separate compilations, the misunderstanding of one routine per file
• fixed form and spaces
• standard input and output
• LU-numbers 5 and 6 (and 7)
• command-line arguments for file names
• real do-variables
• entry
• SAVE-attribute and SAVE as compiler property
• ASSIGN
• arithmetic IF
• computed GOTO
• F66: one-pass do-loops
• statement functions
• six characters
• numerical binary representations versus IEEE (IBM, Cray, Convex)
• big-endian and little-endian
• double complex
• unformatted versus binary files
• list-directed input and output - also: /
• narrow formats
• input formats with decimals - F5.1 and there is no decimal point in the input
• double precision :: x = 1.01 not the same as double precision :: x = 1.01d0
• use of d00 in input
• format statements

old-programming-idioms's Issues

Modernizing

Standardizing for portability, Modernizing to improve the maintainability of the code, and
making old code work because it contains old extensions or removed features all overlap
but have unique issues. One resource to draw on or perhaps to update and expand is

https://fortranwiki.org/fortran/show/Modernizing+Old+Fortran

add topics

I suggest adding topics such as fortran, fortran-tutorial, fortran77 in the About section at https://github.com/arjenmarkus/old-programming-idioms