In powershell, Have Out-Host with conditional statement - powershell

Question

I have a requirement to append | Out-Host with each Powershell execution.
But the response with out-host changes as below
>> some crap
>> $? --> returns false
>> some crap | Out-Host
>> $? --> returns false as expected
>> $(some crap) | Out-Host
>> $? --> returns true not expected
I understand that the true return might be because of the subexpression that I have introduced. But I see it needed in scenarios where I have a conditional script. There simple appending Out-Host doesn't work. For example,
$condition = $true; if ( $condition ) {echo "The condition was true"} | Out-Host
The above fails that an empty pipe is not allowed
If I change it to the below, it works
$($condition = $true; if ( $condition ) {echo "The condition was true"} )| Out-Host
I basically want to append Out-Host such that my output/response of run doesn't get affected. Since Out-Host is said to be the default, there should be a way to handle it for conditional statements as well.
Any help is appreciated.

Answer 1

It's still not entirely clear to me why you need to add Out-Host all over the place, but the safest option for programmatically adding | Out-Host to all your pipelines is to parse the existing script using the Parser class:
function Add-TrailingOutHost {
param(
[string]$Script
)
# Start by parsing the script
$parserErrors = #()
$AST = [System.Management.Automation.Language.Parser]::ParseInput($Script, [ref]$null, [ref]$parserErrors)
if($parserErrors){
Write-Error 'Errors encountered parsing script'
return
}
# Locate all pipeline expressions in the AST returned by the parser
$pipelines = $AST.FindAll({
param($Tree)
# We only want "free-standing" pipelines - ignore pipelines in flow control statements and assignments
$Tree -is [System.Management.Automation.Language.PipelineAst] -and $Tree.Parent -isnot [System.Management.Automation.Language.StatementAst]
}, $true)
# We'll be injecting code into the script, thereby modifying the offsets of the existing statements
# To avoid inject code at the wrong offset we need to traverse the script bottom-up
for($i = $pipelines.Count - 1; $i -ge 0; $i--){
$pipeline = $pipelines[$i]
# Check if the last command in the pipeline is already `Out-*` something - ignore those
$lastCommand = $pipeline.PipelineElements[-1]
if($lastCommand.CommandElements[0] -like 'Out-*'){
continue
}
# Otherwise, inject the string `| Out-Host` at the end of the pipeline
$Script = $Script.Insert($lastCommand.Extent.EndOffset, ' | Out-Host')
}
# return modified script
return $Script
}
Now you can add Out-Host to the relevant parts of any script with:
Add-TrailingOutHost -Script #'
echo "Hello there"
if(Test-Path .){
echo "Something else"
}
'#
The output of which is:
echo "Hello there" | Out-Host
if(Test-Path .){
echo "Something else" | Out-Host
}