ANSI-A4 should take care of most of your library needs.

instead of A5. Linking your code with MacTraps and

but there is a version of the ANSI library that uses A4

ThinkC is fine. The ANSI library does declare globals,

global data references off of register A5. MacTraps of

be taken to ensure that the libraries don't have any

If the ACMD needs to link in library routines, care must



interested.

decade that comes out. IM 6 has a workaround, for those

under A/UX, and probably not under system 8.0, whatever

value of A4 on entry. Self-modifying code will not work

that these routines use self-modifying code to store the

with "RestoreA4()". MPW has similar setup routines. Note

to "RememberA0()" and "SetUpA4()", and it should end

header "SetUpA4.h", your program should begin with calls

this means is that your main file must include the

From the standpoint of a C compiler like Think C, all

their data off of register A4 instead of the usual A5.

Since ACMDs are code resources, they must reference



resource fork by using ResEdit.

bound to keystrokes). ACMDs can be added to Alpha's

callable from macros (macros allow ACMD functions to be

are added to the ACMD menu under 'Utilities' and are

Code resources of type 'ACMD' in Alpha's resource fork



  • The ACMD resource is released.



    transformed text.

  • The original selection is replaced with the



    NULL as it's result.

  • The ACMD transforms the string, and returns it or



    parameters.

    the text pointer and the function pointers as it's

  • The 'ACMD' resource is called as a 'C' function w/



    carriage returns to delimit lines.

    pointer. The string will be null-terminated w/

  • The selection (if any) is copied into the new



    size of the current selection + 1.

  • A new pointer is allocated with size equal to the



    and locked.

  • The selected code resource is loaded into memory



In summary, when an ACMD is called:



used internally.

an Alpha internal variable, only 16 bits are actually

So even while you MUST pass in a longword value to set

variables such as 'indentOnCR' and 'regExpr' are shorts.

Alpha string variables are long words, ordinary Alpha

persistent storage. Note that while user variables and

also hold pointer values, allowing ACMDs to have

defining their own variables. ACMD-defined variables can

are viewing. ACMDs can pass data among themselves by

according to the current state of Alpha and the text you

These functions allow your ACMDs to behave differently





     int deleteVar(char *name);

     *******************************************/

     *                                          *

     * Return 0 if the variable doesn't exist.  *

     * Define a longword variable named 'name'. *

     *                                          *

     /*******************************************





     int defineVar(char *name, long val)

     ************************************************/

     *                                               *

     * Return 0 if the var already exists.           *

     * Initial value 'val'.                          *

     * Define a longword variable named 'name' with  *

     *                                               *

     /************************************************





     int setVar(char *name, long val);

     ***********************************************/

     *                                              *

     * 'val' to a long when you call this routine.  *

     * a longword value for 'val', always typecast  *

     * doesn't exist. To be sure that Think passes  *

     * 'defineVar' below. Returns 0 if the var      *

     * predefined vars or those defined with        *

     * named by 'name'. Works for either Alpha      *

     * Return the longword value of the variable    *

     *                                              *

     /***********************************************





     int getVar(char *name, long *val);

     ***********************************************/

     *                                              *

     * doesn't exist.                               *

     * 'defineVar' below. Returns zero if the var   *

     * Alpha predefined vars or those defined with  *

     * named by 'name' in 'val'. Works for either   *

     * Return the longword value of the variable    *

     *                                              *

     /***********************************************



functions as:

Alpha variables. Internally, Alpha prototypes these

Alpha function that your ACMD can call to read or modify

Each of the last four parameters is a pointer to an



'%ld' instead of '%d'.

with 32-bit ints, you must print your integers with

are calling Alert from a code resource that was compiled

that Alpha is compiled with 16-bit integers, so if you

displaying the result in an alert box.  Bear in mind

accepts the same arguments as the C 'printf' command,

The 'alert' parameter is a pointer to a function that



display information.

ACMD to interact with Alpha's internal variables or

callback function, an Alpha function that allows your

Each of the last five arguments is a pointer to a






Callback Functions



selections.

selected text. However, macros can call ACMDs with other

is performed. 'text' is usually a copy of the currently

when the ACMD returns NULL. In this case no deallocation

block of text returned by the ACMD. The exception is

deallocating the input block. Alpha will deallocate the

two are not the same block, you are responsible for

similarly allocated block of text as its result. If the

allocated with 'NewPtr'. Your routine must return a

'text' points to a null-terminated block of text



     }

        return (text);

         :     :     :

     {

     FPtr    alert, getVar, setVar, defVar, delVar;

     char    *text;

                delVar)

     char *main(text, alert, getVar, setVar, defVar,



     typedef int      (*FPtr)();

     /* pointer to a function that returns an 'int' */



should be declared:

The following is the way the 'main' routine of your ACMD



play sounds.

distribution wrap text, insert the current data, and

ACMD invocations. Example ACMDs included in this

as well as define variables that Alpha maintains between

as a result. ACMDs can access Alpha flags and variables,

the text and returns a pointer to the transformed text

text (usually the selected text). The ACMD transforms

is loaded, it is passed a pointer to a chunk of file

for Alisp functions, or would be too slow. When an ACMD

typically implement functionality that is too complex

modules of user-written code to Alpha. These modules

Code resources of type 'ACMD' allow the user to add




ACMDs