AMT Help Files

Arrays

General

To arrange data fields of the same type and length, you can use arrays. In LION, arrays can have up to 6 dimensions. An array element is filled with characters until the maximum number of characters for that element is reached. If the input for an array element exceeds the maximum number of characters, the extra characters are not stored in the array element.

All values in an array element are indexed uniquely. Because of this, it is allowed to store the same value in more than one element. The first element in a dimension gets the index number "1", the second element gets index number "2", etc.

Arrays are static, so the maximum number of elements that a dimension can contain and the maximum number of characters for a value in an element are predefined by the programmer and cannot be changed afterwards. Arrays can also be defined in a structure. In that case, the total number of elements that is defined in the subarrays cannot exceed the maximal number of elements that is defined for the structure.

You define an array by using the following syntax, which is similar to definitions for constants, variables or boolean functions:

<Array name> : <Type> <Element size> <Array dimensions>
Item Description

<Array name>

 Name of an array.
<Type>

Types of the values to be stored in the array, e.g. alpha, boolean, etc.
<Element size> Maximum number of characters that can be stored in the array element.
<Array dimensions> Array dimensions, written as follows: 
[<Dimension 1>[,<Dimension 2> [,<Dimension
3>[,<Dimension 4>[,<Dimension 5>[,<Dimension
6>]

Array assignments can be written to fill all elements at once, or to fill only one or a selection of element(s).

RESOK

Data Items

For arrays of global and local data items, RESOK is always set when the array is accessed, depending on whether the index is within bounds or out of bounds.

See also table below.

Layout Fields with Occurs

Layout fields with Occurs are accessed in the same manner as arrays of data items (for fields with both horizontal and vertical occurs, the array is two-dimensional).

<Layout Field>[<Index>] := <Value> or <Value> := <Layout Field>[<Index>]

The RESOK behavior differs from the behavior for normal data items:

See also the table below.

This means that if RESOK is used to detect out-of-bounds access to Layout Fields with occurs, RESOK must be set to TRUE for each individual access to a Layout Field array element.

RESOK Matrix

Within bounds: Out of bounds:
Global, local or
data items:		 RESOK = TRUE RESOK = FALSE
Layout controls: RESOK retains
current value. 		RESOK = FALSE

Remarks

When an array is accessed out of bounds, a dummy element is returned. Every array dimension has one dummy element. This dummy element has the same initial value as normal elements. If you assign a value to any out-of-bounds element in the same array dimension, that value is assigned to the dummy element.

Alternatively, AMT can be configured to raise an exception when an array is accessed out of bounds. This is done by using the Exception on array out of bounds setting in Runtime behavior.

Warning
Large arrays take up a lot of memory, especially arrays of strings. On a 64 bit platform each string element will take about 34 bytes of overhead, excluding the length of the string itself. On a 32-bit platform this value is 30 bytes per element.

Examples

{* With the following line an array is created with the name
'SA_ARRAY'. This array consists of 2 dimensions. The 1st dimension
contains 10 elements. The 2nd dimension contains 2 elements.
The values for these elements can contain 5 characters at most. *}
sa_array : alpha 5 [10, 2]

// An array with character based values is initialized like this:
sa_array [ ] := ' '

// An array with numeric based values is initialized like this:
sa_array [ ] := 0

{* With the following line, the value that is stored as the 5th
element of the first dimension and the 1st element of the 2nd
dimension of the array 'SA_ARRAY' is set to '12345'. If the array
is defined like in the 1st example, the sixth character is omitted,
because the array contains only values up to 5 characters. *}
sa_array[5, 1] := '123456'

{* With the following line, the value that is stored in the 5th
element of the first dimension and the 1st element of the
2nd dimension of the array 'SA_ARRAY' is copied to the value that
is stored as the 3rd element of the first dimension and the 2nd
element of the 2nd dimension. *}
sa_array[3, 2] := sa_array[5, 1]

{* With the following code, the 2nd element to the 11th element in
array I will be moved one index number down in the array. *}
loop for j := 1 to 10
  i[j] := i[j+1]
endloop

{* With the following code, the first 10 elements of the array I
will be incremented by 1 *}
loop for j := 1 to 10
  i[j] := i[j] + 1
endloop

// Two examples using ResOk
// Checking out of bounds in an Array
elem[ind] := value

if not ResOk
  sme('Index out of bounds!')
endif

// Checking out of bounds on a screen control with Occurs
ReSok := true
scrncntrl[ind] := value

if not ResOk
  sme('Index out of bounds!')
endif

Initial Values

When setting initial values, all elements can be set to the same value by using the following syntax:

<Array name> : <Type> <Element size> <Array dimension> values all <value>

values all works for all arrays except for structure arrays.

The elements of an array can also be set individually to initial values by using the following syntax:

<Array name> : <Type> <Element size> <Array dimension> values (<value1>, <value2>, ... )

values (,,...) works only for one-dimensional arrays and not for structure arrays.

When setting initial values individually for each element, all elements should be assigned a value.

Examples

num-array : numeric 8 [5] values all 123
num-array2 : numeric 8 [5] values (1, 2, 3, 4, 5)

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