Table of Contents

• 1. astore
  • 1.1. Syntax
  • 1.2. Stack Effects
  • 1.3. Description
  • 1.4. PostScript Level
  • 1.5. Examples
  • 1.6. Common Use Cases
    • 1.6.1. Matrix Construction
    • 1.6.2. Collecting Results
    • 1.6.3. Parameter Arrays
  • 1.7. Common Pitfalls
  • 1.8. Error Conditions
  • 1.9. Implementation Notes
  • 1.10. Comparison with [ ]
  • 1.11. See Also

1. astore

Stores stack elements into an array.

1.1. Syntax

any₀ ... anyₙ₋₁ array astore → array

1.2. Stack Effects

Table 1. Before

Level	Object
n	any₀
…​	…​
1	anyₙ₋₁
0	array (length n)

Table 2. After

Level	Object
0	array (filled with any₀ through anyₙ₋₁)

1.3. Description

astore stores objects from the operand stack into an array:

1. Removes the array from the stack and determines its length n

2. Removes n objects from the stack

3. Stores them into the array (topmost stack element → array[n-1], bottommost → array[0])

4. Pushes the array back onto the stack

The array must have been previously created with the correct length. astore cannot be performed on packed arrays (they are read-only).

1.4. PostScript Level

Level 1 and later

1.5. Examples

Basic storage

(a) (bcd) (ef) 3 array astore
% Result: [(a) (bcd) (ef)]

Building array from computations

10 20 add   % 30
30 40 add   % 70
50 60 add   % 110
3 array astore
% Result: [30 70 110]

Coordinate storage

100 200 2 array astore
/point exch def  % Store as /point

1.6. Common Use Cases

1.6.1. Matrix Construction

1 0 0 1 0 0 6 array astore  % Identity matrix
/identitymatrix exch def

1.6.2. Collecting Results

% Collect multiple function results
func1  % Returns value1
func2  % Returns value2
func3  % Returns value3
3 array astore  % [value1 value2 value3]

1.6.3. Parameter Arrays

/red 1 def /green 0 def /blue 0 def
red green blue 3 array astore
/rgbcolor exch def

1.7. Common Pitfalls

Array Size Must Match - The array must be exactly the right size for the number of objects on the stack.

1 2 3 4 array astore  % Only stores 3 items
% 4th element remains null

Stack Order - Objects are stored in reverse stack order: topmost stack element → highest array index.

1 2 3 3 array astore  % Result: [1 2 3]
                       % NOT [3 2 1]

Global/Local VM Restrictions - If the array is in global VM and any stored object is in local VM, [invalidaccess] error occurs.

Pre-create Array - Always create the array first with the correct size using array.

1.8. Error Conditions

Error	Condition
[invalidaccess]	Array is in global VM and contains local VM objects, or array is read-only
[stackunderflow]	Fewer than n+1 objects on stack
[typecheck]	Operand is not an array

1.9. Implementation Notes

• Cannot be used with packed arrays (they are read-only)

• Elements are stored by reference (not copied) for composite objects

• The array is modified in place

• Most efficient for small to medium-sized arrays

1.10. Comparison with [ ]

% Using astore
1 2 3 3 array astore  % [1 2 3]

% Using [ ]
[ 1 2 3 ]             % [1 2 3] (more convenient)

The [ ] syntax is usually more convenient for literal arrays, but astore is useful when the array size is computed dynamically.

1.11. See Also

• aload - Load array elements onto stack

• array - Create new array

• put - Put single value into array

• putinterval - Put subarray into array

• [ / ] - Array literal syntax