[PD-announce] k_cext V0.2.4

[Kjetil S. Matheussen]

http://www.notam02.no/~kjetism/pd/bin/k_cext-0.2.4.tar.gz



k_cext PD external


INTRODUCTION

        The k_cext PD external makes you able to program
        the programming language "C" directly within
        the PD objects.

        +-------------------------------------------------------+
        | Which means: You don't need an external text-editor.  |
        +-------------------------------------------------------+



WHY USE K_CEXT

        The reason for using "C" in k_cext was simply because it is
        so simple to compile and link c code inside externals in pd.
        C is probably not the best suited language for this task, except
        when extreme cpu-efficiency is needed.

        Still, I personally think making small k_cext objects
        is a lot more comfortable than making large pd sub-patches
        doing the same things. And thats probably the main reason
        to use k_cext.




A SMALL EXAMPLE IN K_CEXT

        The following k_cext object have one inlet and one outlet.
        What it does, when receiving a value on the inlet, is to
        send the _previously_ received inlet value to the outlet.


        [ k_cext 1 1;
          static t_float prev=0;
          O(0,prev);
          prev=V(0); ]


        The "k_cext 1 1" line is the k_cext header. The first "1"
        means that it uses one inlet, and the second "1" means that
        it uses one outlet.

        The "static t_float prev=0;" line declares a variable for the
        object called "prev". "t_float" means that the type of the
        variable is
        a floating-point number. "static" means here that the value
        for the variable is remembered the next time the object
        is runned, which is necesarry if we want to send out the
        previous value sent to the inlet.

        "O(0,prev);" sends the value of "prev" to outlet number 0.
        "O" is a function.

        "prev=V(0);" stores the value of the current inlet to the
        variable "prev" for the next time the object is run.



THE SAME EXAMPLE AS A PD SUB-PATCH


        The following PD-patch does the same:

        [inlet]
        |
        +-------+
        |       |
        [bang]  |
        |       |
        [ float ]
        |
        [outlet]

        You must also make sure that the inlet->bang connection
        is made before the inlet->float connection.

        I guess its a matter of personal taste, but I really don't
        find the PD-way of sending out a previous value very intuitive.
        And especially not the requirement to create the connections in
        a certain order to make a patch function correctly.

        In addition, the advantage of using k_cext instead of making
        PD sub-patches becomes more appearent the larger the tasks are.
        Look at the help-file, and try to do the same things directly in
        PD.



K_CEXT OBJECT

        A k_cext object can be divided into three parts:

        1. Header.
        2. Variables
        3. Body.



K_CEXT HEADER

        The first line in a k_cext header is built up like this:

        "k_cext <num_inlets> <num_outlets> <default inlet values>".

        "k_cext 4 5 1 2 3 4" means that the object has 4 inlets,
        5 outlets, and the value of V(0) is by default 1, the
        value of V(1) is by default 2, the value of V(2) is by
        default 3, and the value of V(3) is by default 4.

        Its optional whether you want to set "default inlet values"
        or not. If not set, they get the value 0.


K_CEXT VARIABLES

        There are four types of variables that makes sense using
        in a k_cext object. These are:

        "int" - integer number.
        "t_float" - floating point numbes
        "INTARRAY" - An array of integer numbers.
        "FLOATARRAY" - An array of floating point numbers.

        See the help patch for examples of use.



MACROS / USING THE PD OBJECT AS A TEXT-EDITOR

        Using the pd object as a text-editor is unfortunately
        a bit limited. But by using some pre-defined macros
        spesified in the "k_cext.h" file, its not that bad.

        begin/end -
                The most noticable limitation is probably that you are
                not able to write { or }. This is solved easely by
                using the BEGIN and END macros.

        lineshift -
                The pd object text editor doesn't understand lineshift
                directly. Instead you have to use ";" at the end
                of each line.

        semicolon -
                If you need to write ";", but dont want the line to end
                right there, use the "SC" macro instead.

        indentation -
                The pd object text editor automaticly removes spaces and
                tabs from the beginning of lines. You can work around this
                by
                writing ". " instead. The k_cext external removes all
                ". "'s at the beginning of lines before compiling the
                code.


        More macros are defined in the k_cext.h header file.



OS
        k_cext runs fine in linux using gcc and in windows using visual C.
        The macosx code was made by looking at code inside PD, and has
        never
        been tested (at least not that I know if). It might work, but
        probably
        not. Check out the k_cext_macosx.c file.


FAQ
        Q: I can not get k_cext to work in windows, and I dont have Visual C.
        A: You need Visual C.


CHANGES
        0.2.3 -> 0.2.4:
        -Added a lot of new macros to k_cext.h.
        -Fixed the help file a bit.
        -Wrote the README file.
        -Changed the license for k_cext.h from GPL to LGPL.
         (Note, the k_cext external is still GPL)
        -Some windows code was for some strange reason put
         in the macosx file. Fixed.
        -Added Mac OSX to the Makefile. (Not tested.)


CREDITS
        k_cext is made by Kjetil S. Matheussen 2002/2003.
        k.s.matheussen at notam02.no

        The windows-port is made by Olaf Matthes.
        olaf.matthes at gmx.de





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