how to declare an array of unknown size

I'm not 100% certain what you're after. First of all, arrays can be declared on the fly - so you can create arrays with the size based on a variable - if that's what you want, that's easy. For example, this code here provides a way to create multi-dimensional arrays simply:

/* abMultiDimArray.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Nov 23, 2009 
Modified   
By         

Function for creating a multi-dimensional array.

Usage:

data=abMultiDimArray(6 8)

Creates a 6 by 8 array (starting index is from 0). Then you can use:

data[4][5]=23
data[0][7]=123

You can specify more dimensions by passing more arguments to abMultiDimArray.

***************************************************

SCCS Info: @(#) abMultiDimArray.il 11/23/09.16:24:27 1.1

*/

procedure(abMultiDimArray(@rest dimensions)
    let((arr)
        if(integerp(car(dimensions)) && plusp(car(dimensions)) then
            arr=makeVector(car(dimensions))
            when(cdr(dimensions)
                for(ind 0 sub1(car(dimensions))
                    arr[ind]=apply('abMultiDimArray cdr(dimensions))
                )
            ) ; when 
            arr
        else
            error("Dimension %L must be a positive integer\n" car(dimensions))
        ) ; if
    ) ; let
) ; procedure

If however you're asking for a way to declare an array of a certain size, and then make it bigger later, then I would question whether you really want an array. You could either use a list for this dynamic data structure, or you could use a hash (association) table. Which you would use depends on how it is going to be accessed. Lists are good if you can traverse them sequentially, but not good if you want to access the data in a random-access fashion (e.g. you want to access the 10th, or the 15th, or the 2453th entry arbitrarily). Hash tables are good if you want to access the data with random access, but no good if you want any kind of order.

A table could be created using:

myArr=makeTable('myArray)

and then you could use:

myArr[0]=1
myArr[1]=2

and you can arbitrarily add indices later - they can be sparse too - so doing myArr[123456789]=3 is perfectly OK and doesn't have to allocate all the space for the intervening indices. The downside is that the keys are not in any order - so doing myArr->? would give you the keys in some arbitrary order - but provided you're treating it like an array, that shouldn't be an issue.

Regards,

Andrew.

I'm not 100% certain what you're after. First of all, arrays can be declared on the fly - so you can create arrays with the size based on a variable - if that's what you want, that's easy. For example, this code here provides a way to create multi-dimensional arrays simply:

/* abMultiDimArray.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Nov 23, 2009 
Modified   
By         

Function for creating a multi-dimensional array.

Usage:

data=abMultiDimArray(6 8)

Creates a 6 by 8 array (starting index is from 0). Then you can use:

data[4][5]=23
data[0][7]=123

You can specify more dimensions by passing more arguments to abMultiDimArray.

***************************************************

SCCS Info: @(#) abMultiDimArray.il 11/23/09.16:24:27 1.1

*/

procedure(abMultiDimArray(@rest dimensions)
    let((arr)
        if(integerp(car(dimensions)) && plusp(car(dimensions)) then
            arr=makeVector(car(dimensions))
            when(cdr(dimensions)
                for(ind 0 sub1(car(dimensions))
                    arr[ind]=apply('abMultiDimArray cdr(dimensions))
                )
            ) ; when 
            arr
        else
            error("Dimension %L must be a positive integer\n" car(dimensions))
        ) ; if
    ) ; let
) ; procedure

If however you're asking for a way to declare an array of a certain size, and then make it bigger later, then I would question whether you really want an array. You could either use a list for this dynamic data structure, or you could use a hash (association) table. Which you would use depends on how it is going to be accessed. Lists are good if you can traverse them sequentially, but not good if you want to access the data in a random-access fashion (e.g. you want to access the 10th, or the 15th, or the 2453th entry arbitrarily). Hash tables are good if you want to access the data with random access, but no good if you want any kind of order.

A table could be created using:

myArr=makeTable('myArray)

and then you could use:

myArr[0]=1
myArr[1]=2

and you can arbitrarily add indices later - they can be sparse too - so doing myArr[123456789]=3 is perfectly OK and doesn't have to allocate all the space for the intervening indices. The downside is that the keys are not in any order - so doing myArr->? would give you the keys in some arbitrary order - but provided you're treating it like an array, that shouldn't be an issue.

Regards,

Andrew.