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MiniRobotLanguage (MRL)
ARS.PeekFirst
Peek at the first element of the Deque without removing it.
Intention
The ARS.PeekFirst command allows you to view the first element of the Deque without removing it. This is useful for inspecting the element at the front of the Deque without altering its contents.
Illustration:
Deque Structure:
┌───────────────┐
│ FirstElement │ ← Peeked
├───────────────┤
│ SecondElement │
├───────────────┤
│ LastElement │
└───────────────┘
The last element is inspected but remains in the Deque.
Syntax
ARS.PeekFirst|$$DEQ|$$RES
Parameter Explanation
P1 - $$DEQ The handle of the Deque.
P2 - $$RES The variable to store the first element of the Deque.
Example
'***********************************
' ARS.PeekFirst - Sample Script
'***********************************
' Create a new Deque
ARS.New|$$DEQ
' Push elements onto the Deque
ARS.PushFirst|$$DEQ|FirstElement
ARS.PushLast|$$DEQ|LastElement
' Peek at the first element
ARS.PeekFirst|$$DEQ|$$RES
DBP.The first element is: $$RES
' End the script
ENR.
Remarks
-
Limitations:
- The Deque must not be empty when using this command.
See also:
• ARS.New