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Precompiler define

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Revision as of 15:41, 30 December 2007

Definition

#define <what to define> [<what it will be>]

Defines what to define as what it will be. This means that after this line, all what to defines will be "replaced" by what it will be.

You can also create "functions" with this, even with parameters. The call to this "function", including parameters, will be replaced by the what it will be section, with the parameters replaced by the arguments.

Example

In the following example, we'll show it is possible to define words as "being" basic statements.

#define StartThisShow Program
#define GimmeSomeShit Process

StartThisShow example;
Begin
    proc();
End

GimmeSomeShit proc()
Begin
End

Used in example: Program, Process, Begin, End

Error codes are handy as well, like used in Network.DLL and LCD.DLL:

#define NET_ERROR_INVALIDADDRESS -12

This will enable the use of NET_ERROR_INVALIDADDRESS as it it were the value -12. This makes it much more clear for the programmer what the errors are. Consider this:

#define NET_STATUS_ESTABLISHED 2

The value 2 on itself means very little, but NET_STATUS_ESTABLISHED immediately makes it clear what it means.

In the following we define a function kill(<int processID|processTypeID>,<string reason>).

#define kill(a,b) if(exists(a)) signal(a,s_kill); say("Killed '" + a + "' for reason: " + b); end
Program example;
Begin
    x = proc();
    kill(x,"It had to be killed!"); // The ';' is not needed per se, but is allowed.
    Repeat
        frame;
    Until(key(_ESC))
End
Process proc()
Begin
    Loop
        frame;
    End
End