1: #pragma once

  3: #include <petscmacros.h>

  5: /* ------------------------------ Like petscmacros.h but advanced ------------------------------ */

  7: #define PETSC_IF_INTERNAL_0(result_if_true, ...) __VA_ARGS__
  8: #define PETSC_IF_INTERNAL_1(result_if_true, ...) result_if_true

 10: /*
 11:   PetscIf - Conditionally expand to the second or remaining args

 13:   No Fortran Support

 15:   Input Parameters:
 16: + cond           - Preprocessor conditional
 17: . result_if_true - Result of macro expansion if `cond` expands to 1
 18: - __VA_ARGS__    - Result of macro expansion if `cond` expands to 0

 20:   Level: intermediate

 22:   Note:
 23:   `cond` must be defined and expand (not evaluate!) to either integer literal 0 or 1. Must have
 24:   at least 1 argument for `__VA_ARGS__`, but it may expand empty.

 26:   Example usage:
 27: .vb
 28:   void myFunction(int,char*);
 29:   #define MY_VAR 1
 30:   PetscIf(MY_VAR,"hello","goodbye") -> "hello"
 31:   PetscIf(MY_VAR,myFunction,PetscExpandToNothing)(1,"hello") -> myFunction(1,"hello")

 33:   #define MY_VAR 0
 34:   PetscIf(MY_VAR,"hello",func<type1,type2>()) -> func<type1,type2>()
 35:   PetscIf(MY_VAR,myFunction,PetscExpandToNothing)(1,"hello") -> *nothing*
 36: .ve

 38: .seealso: `PetscIfPetscDefined()`, `PetscConcat()`, `PetscExpandToNothing()`, `PetscCompl()`
 39: */
 40: #define PetscIf(cond, result_if_true, ...) PetscConcat_(PETSC_IF_INTERNAL_, cond)(result_if_true, __VA_ARGS__)

 42: /*
 43:   PetscIfPetscDefined - Like `PetscIf()`, but passes `cond` through `PetscDefined()` first

 45:   No Fortran Support

 47:   Input Parameters:
 48: + cond           - Condition passed to `PetscDefined()`
 49: . result_if_true - Result of macro expansion if `PetscDefined(cond)` expands to 1
 50: - __VA_ARGS__    - Result of macro expansion if `PetscDefined(cond)` expands to 0

 52:   Level: intermediate

 54:   Note:
 55:   `cond` must satisfy all conditions for `PetscDefined()`. It must have at least 1 argument for
 56:   `__VA_ARGS__`, but it may expand empty.

 58:   Example usage:
 59: .vb
 60:   #define PETSC_HAVE_FOO 1
 61:   PetscIfPetscDefined(HAVE_FOO,foo,bar) -> foo

 63:   #undef PETSC_HAVE_FOO
 64:   PetscIfPetscDefined(HAVE_FOO,foo,bar,baz,bop) -> bar,baz,bop
 65: .ve

 67: .seealso: `PetscIf()`, `PetscDefined()`, `PetscConcat()`, `PetscExpand()`, `PetscCompl()`
 68: */
 69: #define PetscIfPetscDefined(cond, result_if_true, ...) PetscIf(PetscDefined(cond), result_if_true, __VA_ARGS__)