NAME¶

if-defined - (program-flow)

PURPOSE¶

Conditional compilation.

SYNTAX¶

if-defined <symbol>


    <any code>
end-defined
if-defined <symbol> [ equal | not-equal | lesser-than | lesser-equal | greater-than | greater-equal ] <number>


    <any code>
end-defined
if-not-defined <symbol>


    <any code>
end-defined

DESCRIPTION¶

Without a comparison clause, if-defined will cause <any code> to be compiled if <symbol> is defined (see "--cflag" option in gg); if <symbol> is not defined, then <any code> is not compiled.

With a comparison clause, if-defined will cause <any code> to be compiled if <symbol> is equal/not equal/lesser than/lesser or equal/greater than/greater or equal than <number> constant, depending on the clause used (see "--cflag" option in gg). If <symbol> is not defined, then its value is assumed to be 0, and <any code> may still be compiled if the comparison clause and the <number> are such that the condition is true for <symbol> being 0.

if-not-defined will cause <any code> to be compiled if <symbol> is not defined (see "--cflag" option in gg); if <symbol> is defined, then <any code> is not compiled.

Note that <symbol> can start with an underscore, unlike Golf variable names; this is because defined symbols aren't variables and generally are set by the outside environment or during compilation (see "--cflag" option in gg).

EXAMPLES¶

The following code will have a different output depending on how is the application compiled:

if-defined DEF1


    @Defined
end-defined
if-not-defined DEF1


    @Not defined
end-defined
if-defined DEF2 equal 10


    @DEF2 is 10
end-defined
if-defined DEF2 equal 0


    @DEF2 is 0
end-defined

If compiled with:

gg -q

then the output is:

Not defined
DEF2 is 0