Using the Begin-process-end for Powershell. What are the benefits? - powershell

Question

i'm currently trying to do a small script to retrieve data from a server using REST endpoint. As it's the first time i work with powershell, i'm a bit disappointed by the 'lack' of structure and 'typing' in it.
Then i structured my code like this with comments :
# declare ------------------------------------------------------------------------------------------
// All the var i'll need in my process
# do -----------------------------------------------------------------------------------------------
// Ask for user to enter URL and credentials
// Check if credentials are correct
// Connect to the server
// Retrieves the data in a list (JSON formatted) --> List REST EndPoint
// Foreach document in my list
// retrieve the document's details --> single file REST EndPoint
// download the file into local directory
// End Foreach
# display results ----------------------------------------------------------------------------------
// display :
// Downloaded files
// Non-Downloaded files
During review, my colleague told me "Oh ! What you need is the 'begin-process-end' " and then just leave.
I then read somethings about this here but for what i see, the structure is the same as i did with my comments but i don't see the point where it's "What i need" as a functionalities.
Since i'm a real beginner, i maybe miss the point. Could you explain it to me ?
(btw, thx to the kind person who'll edit my ugly english mistakes)

Answer 1

Think of these blocks as a pre-processor (the begin block), actual processor (the process block), and a post-processor(the end block) to a function.
You don't need to define any of these blocks (although Begin and End block will always need a Process block), and can write code just fine without them, but the idea behind them is to divide the function into three separate areas of code. The following function should make it a little clearer:
function addition_by_one {
# Arguments to a powershell functions are defined inside the param block.
Param (
[int]$number
)
# In the below begin block, the variable $a was initialized to 1.
Begin {
$a = 1
}
# The Process block does the main work. In this case, $a is added to the argument supplied to the function.
Process {
$sum = $number + $a
}
# Finally, the End block will execute after the process block completes.
End {
"Sum is $sum"
}
}
# Call the function with any integer argument.
addition_by_one -number 3

Answer 2

Being/process/end is really for pipelines. You can't process from the pipe without a process block.
1..5 | & { process {$_ * 2} }
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