Determine variable names dynamically according to a string in Fortran

by

I fear that you will not be able to do this. Fortran requires that variables have names and types at compile time. You (or other SOers) may come up with some kludge to simulate what you want, but it will be a kludge.

Why do you want to do this in Fortran ? There are plenty of languages around which do permit this sort of variable declaration.

EDIT

Well, I thought about it some more, and here’s a kludge, unfinished. First a UDT for ‘dynamic’ variables:

type dynamic_var
  character(len=:), allocatable :: label
  class(*), allocatable :: value
end type

declare some space for such variables:

type(dynamic_var), dimension(:), allocatable :: run_time_vars

and, working with your original data

allocate(run_time_vars(10)) ! No error checking, reallocate if necessary
! lots of code
write(run_time_vars(1)%label,'(a1,i1)') my_string, my_integer
allocate(run_time_vars(1)%value, source = my_value)

This compiles, but doesn’t run and I’m not going to stay long enough to fix it, I’ll leave that as an exercise to anyone who cares.

  • The write to the label field isn’t right.
  • The sourced allocation to the value field doesn’t seem to work correctly. Might need to write a ‘decode’ function to use like this:

allocate(run_time_vars(1)%value, source = decode(my_value))

Like I said, it’s a kludge.

More Related Contents:

  1. How to get variable name?
  2. Creating or referencing variables dynamically in Sass
  3. Error if don’t check if {{object.field}} exists
  4. When should an Excel VBA variable be killed or set to Nothing?
  5. Why are variables “i” and “j” used for counters?
  6. Which variable size to use (db, dw, dd) with x86 assembly?
  7. When should I quote CMake variables?
  8. HiveQL: Using query results as variables
  9. Dynamically create variables in PowerShell
  10. In Rust, what’s the difference between “shadowing” and “mutability”?
  11. LessCss dynamic variables based on ancestor class
  12. Is it possible to create a multi-line string variable in a Makefile
  13. Powershell pass variable to start-job
  14. How to make points one color when a third column equals zero, and another color otherwise, in Gnuplot?
  15. Batch File Set Variable not working [duplicate]
  16. Why there are two ways of declaring variables in Go, what’s the difference and which to use?
  17. In MATLAB, are variables REALLY double-precision by default?
  18. Multiple variable assignment in Swift
  19. Why are variables “i” and “j” used for counters?
  20. Dynamic Variable Naming and Reference (ColdFusion)
  21. Windows Batch files: what is variable expansion, and what does EnableDelayedExpansion mean?
  22. gnuplot store one number from data file into variable
  23. Are local variables in Fortran 77 static or stack dynamic?
  24. What is the order of local variables on the stack?
  25. What is “_,” (underscore comma) in a Go declaration?
  26. Set fact with dynamic key name in ansible
  27. Declaring global variable with php.ini
  28. Why does Go allow compilation of unused function parameters?
  29. Create a variable in swift with dynamic name
  30. Finding out reason of Pyomo model infeasibility

Leave a Comment