A rudimentary array macro

mikeabuilder

No question or issue, just sharing something.

A thread in this forum mentioned having macros write their own macros and it occurred to me maybe this could work to make a rudimentary array. It festered in my brain like the last few words in the NY Times Sunday crossword. This morning I got it working. The code is below, but I'll describe how it works and it's shortcomings.

A new array is initialized when a macro that needs an array calls the code below using an M98. The user supplies an array name. Then the macro below echos commands into a file with the array name. Now this newly-created macro (say my_array.g) can be called from the original macro. It supports adding new elements, changing the value of existing elements and querying the value of existing elements. When called, it puts the appropriate return value into a global variable called "global.array_response". So it only clogs memory with a single additional global variable.

Writing it was a bit of a mind-bender because of nested echos to files and their associated escaped quote marks, the array macro appending to itself when an element is added or changed, and the need for the array macro to call itself to find it's own length so it can increment the array index when adding an element. Also, in the initialization macro, the echoed strings all needed to be kept under the length limit.

The shortcoming of this macro is that it will allow the user to replace a value at an index that is outside the length of the array (say, replace loc[10] when the array is only three elements long). This will then add a gap in the array for future normal adds. I might work on that. This same shortcoming would also let someone use this as a data dictionary, using strings as the array index parameter.

Now I need to find a reason to use an array in a macro...

; Array.g is a macro intended to be used by other macros to manage data in an array-like structure. 
; You call array.g once to create an array macro.  You call that macro add an element to the array, 
; read the value at a specified index, get the length of the array, or replace a value at an existing index. 

; This macro creates the array in a /temp sub-folder of the sys directory, but you can change the location if you want.
; Author: mikeabuilder

; One day, if RRF adds array support to the core RRF funstionality, this macro will no longer be needed.
; That will be a happy day. 

var Array_location = "0:/sys/temp/"



; Typical usage
;  M98 P"0:/sys/array.g" S"array name"
;
;Parameter definition and usage
;  S"array_name"  Required parameter. This is the name of an array you want to create. If you use a name that was used previously, the old array will be overwritten.

; PARAMETER CHECK
if !exists(param.S)
  M291 P"No macro name provided. Cancelling array build" S3 T-1
  M99

var file = var.Array_location^param.S^".g"  ;create full path to the new array


; The following lines are all echoed into the new array file
echo >{var.file}  "; This file was created by the macro array.g, normally located in the /sys directory."
echo >>{var.file} "; It is used as method for creating a rudimentary array data capability for other macros."
echo >>{var.file} "; This macro is called to add elements to the array, read values of an existing element,"
echo >>{var.file} "; change the values of existing element, or get the number of elements in the array."
echo >>{var.file} "; The requested data is passed back to the calling macro by putting it into a global "
echo >>{var.file} "; variable called gloabl.macro_response."
echo >>{var.file} "; Author: mikeabuilder"
echo >>{var.file} "; "
echo >>{var.file} "; TYPICAL USE"
echo >>{var.file} "; M98 P""0:/sys/temp/"^var.file^""" V""value""  I""index"" L                "
echo >>{var.file} "; "
echo >>{var.file} "; PARAMETERS"
echo >>{var.file} ";  V""value""   When used without the I parameter, the value is appended to that array as a new     "
echo >>{var.file} ";               element. The value of global.macro_response is set to the array index of the added  "
echo >>{var.file} ";               value.                                                                              "
echo >>{var.file} ";  I""number""  When used without the A parameter, the value of element I[number] is returned in    "
echo >>{var.file} ";             global.macro_response.                                                                "
echo >>{var.file} ";             When both A and I parameters are used, the existing value of the element I[number] is "
echo >>{var.file} ";             replaced. If there is no element I[number], a new element I[number] is created. It    "
echo >>{var.file} ";             might get overwritten.                                                                "
echo >>{var.file} ";  None       If no parameter is present, the length of the array is returned in                    "
echo >>{var.file} ";             global.array_response.                                                                "
echo >>{var.file} "; "
echo >>{var.file} "; THEORY OF OPERATION"
echo >>{var.file} "; When array elemenmts are added or changed, they are added to the end of this macro file. Changed  "
echo >>{var.file} "; element values result is multiple values in this file. The valie closest to the end of the file is"
echo >>{var.file} "; the current value. This means that a value that is changed a lot will make the file longer and    "
echo >>{var.file} "; longer. Simple enough, eh? "
echo >>{var.file} ""
echo >>{var.file} ""
echo >>{var.file} ";START OF THE REAL WORK"
echo >>{var.file} ""
echo >>{var.file} "; If we are appending or replacing, this is the easy part"
echo >>{var.file} "; Set up some variables"
echo >>{var.file} "var index = 0                                                                                       "
echo >>{var.file} "if !exists(global.array_response)                                                                   "
echo >>{var.file} "  global array_response = var.index                                                                 "
echo >>{var.file} "else                                                                                                "
echo >>{var.file} "  set global.array_response = var.index                                                             "

echo >>{var.file} "var my_len = 0                                                                                      "
echo >>{var.file} {"var file = """^var.file^""""}
echo >>{var.file} ""
echo >>{var.file} "; If we are adding a new element or changing the value of an existing element it happens here.      "
echo >>{var.file} "if exists(param.V)          ; We are appending or changing                                          "
echo >>{var.file} "  if exists(param.I)        ; An index is supplied, so we are changing a value                      "
echo >>{var.file} "    set var.index = param.I  ; The user supplied the index for the element to be replaced           "
echo >>{var.file} "  else                      ; We are adding a new element so we need to get the next unused index   "
echo >>{var.file} "    M98 P"""^{var.file}^"""  ; query myself for the length of my array                              "
echo >>{var.file} "    set var.index = global.array_response  ; The array length is the next index                     "
echo >>{var.file} "                                                                                                    "
echo >>{var.file} "  ; we have the index and the value to add, so lets add to our own file                             "
echo >>{var.file} "  "
echo >>{var.file} "  echo >>{var.file} ""       ;NEXT ARRAY ELEMENT""                                                  "
echo >>{var.file} "  echo >>{var.file} ""if exists(param.I)  ; we are returning an existing value""                    "
echo >>{var.file} "  echo >>{var.file} ""  if param.I = ""^var.index                                                   "
echo >>{var.file} "  echo >>{var.file} ""  set global.array_response = """"""^param.V^""""""""                         "
echo >>{var.file} "  echo >>{var.file} ""else""                                                                        "
echo >>{var.file} "  echo >>{var.file} ""  set var.my_len = max(global.array_response,""^var.index+1^"")""             "
echo >>{var.file} "  echo >>{var.file} ""  set global.array_response= var.my_len""                                     "
echo >>{var.file} ";  "

OwenD

@mikeabuilder
Great job!