Using the tenary operator in C with 3 numbers

[a740g]

Well, until we get a short-circuiting ternary operator in QB64-PE.   

Here is my attempt, just for fun.

My version brazenly exploits how QB64 uses the C++ compiler. This correctly eliminates the part that doesn't require evaluation.

Cheers!


Save as iif.h

Code: (Select All)

#pragma once

#define qb64_iif(qb64_iif_expression, qb64_iif_true_part, qb64_iif_false_part) ((qb64_iif_expression) ? (qb64_iif_true_part) : (qb64_iif_false_part))

Code: (Select All)

OPTION _EXPLICIT



DECLARE LIBRARY "iif"

    FUNCTION IIf_Byte%% ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS _BYTE, BYVAL falsePart AS _BYTE)

    FUNCTION IIf_UByte~%% ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS _UNSIGNED _BYTE, BYVAL falsePart AS _UNSIGNED _BYTE)

    FUNCTION IIf_Integer% ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS INTEGER, BYVAL falsePart AS INTEGER)

    FUNCTION IIf_Uinteger~% ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS _UNSIGNED INTEGER, BYVAL falsePart AS _UNSIGNED INTEGER)

    FUNCTION IIf_Long& ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS LONG, BYVAL falsePart AS LONG)

    FUNCTION IIf_ULong~& ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS _UNSIGNED LONG, BYVAL falsePart AS _UNSIGNED LONG)

    FUNCTION IIf_Integer64&& ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS _INTEGER64, BYVAL falsePart AS _INTEGER64)

    FUNCTION IIf_UInteger64~&& ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS _UNSIGNED _INTEGER64, BYVAL falsePart AS _UNSIGNED _INTEGER64)

    FUNCTION IIf_Single! ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS SINGLE, BYVAL falsePart AS SINGLE)

    FUNCTION IIf_Double# ALIAS "qb64_iif" (BYVAL expression AS _OFFSET, BYVAL truePart AS DOUBLE, BYVAL falsePart AS DOUBLE)

END DECLARE



DIM i AS LONG



PRINT IIf_Long(i > 10, foo, bar) ' foo should not evaluate



i = 100



PRINT IIf_Long(i > 10, foo, bar) ' bar should not evaluate



END



FUNCTION foo&

    PRINT "Foo called!"

    foo = 512

END FUNCTION



FUNCTION bar&

    PRINT "Bar called!"

    bar = 128

END FUNCTION