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Commenting a Procedure: description

The description command in Darwin provides a means of documenting a procedure.

> SetAverage := proc(s : set)
>   local total;
>   description 'This procedure takes a set as an argument and
>                calculates the average value in the set';
>   total := 0:
>   for i from 1 to length(s) do
>     total := total + s[i];
>   od;
>   print('The average is ', total/length(s));
> end:
If we type
> print(SetAverage);
the text surrounded by the single quote symbols (') following the description command is echoed to the terminal.
SetAverage: Usage: SetAverage( s:set )
This procedure takes a set as an argument and
 calculates the average value in the set

The description command must follow any local or global declarations and any option commands.

> example := proc( ... )
>   local x, y, z;
>   global a, b, c,;
>   option polymorphic;
>   description 'The following text is displayed by the print command';
    . . .
>end:

Computer science wisdom says that writing clear meaningful comments in your routines makes for easier to understand and debug code. However, the description command is optional.



Gaston Gonnet
1998-09-15