| Version 2 (modified by Charles, 12 years ago) |
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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:
@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:
@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.
