= If Directive =

This does not describe an existing feature. It's place to jot down notes for my idea of an @if directive and related features.

== Motivation ==

Conditional inclusion of source code (aka "conditional compilation") is needed in some circumstances. Some of the better known ones are:
 * Adjusting for the back-end (CLR, JVM)
 * Demo vs. Production
 * Debug or not
 * Adjusting for compiler options (-include-tests, etc.)

Other languages including C# (#if, #define) and D (static if, version, ...) have condition compilation features which are taken advantage of by their communities.

== Syntax ==

General, full form:
{{{
#!cobra
@if <condition>
   <code>
@else if <condition>
   <code>
@else
   <code>
}}}
But "@else if" and "@else" are optional and "@else if" can be repeated.

== Defining Symbols ==

{{{
cobra -define:FOO -define:FOO=bar ...
}}}

Or in code:
{{{
#!cobra
@define FOO
@define FOO = 'bar'
}}}

== Automatic Symbols ==

CLR, CLR20, CLR40, JVM, JVM16, JVM17, JVM18, OBJC, DOTNET, MONO, WINDOWS, UNIX, MAC, ASSERTS, TESTS, CONTRACTS, DEBUG, DST, ERT

... or we could go all lower case:

clr, jvm, objc, dotnet, etc.


== See Also ==

 * Discussion at http://cobra-language.com/forums/viewtopic.php?f=4&t=966
 * CompilerDirectives
 * LanguageTopics