Emulating namespaces in Fortran 90

Question

One of the most troublesome issues with Fortran 90 is the lack of namespacing. In this previous question \"How do you use Fortran 90 module data\" from Pete, it has been dis

Answer 1

For me this is the most irritating Fortran feature related to modules. The only solution is to add common prefix to procedures, variables, constants, etc. to avoid namespace collisions.

One can prefix all entities (all public entities seems to be more appropriate) right inside the module:

module constants

  implicit none

  real, parameter :: constants_pi = 3.14
  real, parameter :: constants_e = 2.71828183

end module constants

Drawback is increased code verbosity inside the module. As an alternative one can use namespace-prefix wrapper module as suggested here, for example.

module constants_internal

  implicit none

  real, parameter :: pi = 3.14
  real, parameter :: e = 2.71828183

end module constants_internal

module constants

  use constants_internal, only: &
    constants_pi => pi, &
    constants_e => e

end module constants

The last is a small modification of what you, Stefano, suggested.

Even if we accept the situation with verbosity the fact that Fortran is not case-sensitive language force us to use the same separator (_) in entities names. And it will be really difficult to distinguish module name (as a prefix) from entity name until we do not use strong naming discipline, for example, module names are one word only.