Transpilers/Syntax/Dot.psx.ps1
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<# .SYNOPSIS Dot Notation .DESCRIPTION Dot Notation simplifies multiple operations on one or more objects. Any command named . (followed by a letter) will be treated as the name of a method or property. If it is followed by parenthesis, these will be treated as method arguments. If it is followed by a ScriptBlock, a dynamic property will be created that will return the result of that script block. If any other arguments are found before the next .Name, they will be considered arguments to a method. .EXAMPLE .> { [DateTime]::now | .Month .Day .Year } .EXAMPLE .> { "abc", "123", "abc123" | .Length } .EXAMPLE .> { 1.99 | .ToString 'C' [CultureInfo]'gb-gb' } .EXAMPLE .> { 1.99 | .ToString('C') } .EXAMPLE .> { 1..5 | .Number { $_ } .Even { -not ($_ % 2) } .Odd { ($_ % 2) -as [bool]} } .EXAMPLE .> { .ID { Get-Random } .Count { 0 } .Total { 10 }} .EXAMPLE .> { # Declare a new object .Property = "ConstantValue" .Numbers = 1..100 .Double = { param($n) $n * 2 } .EvenNumbers = { $this.Numbers | Where-Object { -not ($_ % 2)} } .OddNumbers = { $this.Numbers | Where-Object { $_ % 2} } } #> [ValidateScript({ $commandAst = $_ $DotChainPattern = '^\.\p{L}' if (-not $commandAst.CommandElements) { return $false } $commandAst.CommandElements[0].Value -match $DotChainPattern })] param( [Parameter(Mandatory,ParameterSetName='Command',ValueFromPipeline)] [Management.Automation.Language.CommandAst] $CommandAst ) begin { $DotProperty = { if ($in.PSObject.Methods[$PropertyName].OverloadDefinitions -match '\(\)$') { $in.$PropertyName.Invoke() } elseif ($in.PSObject.Properties[$PropertyName]) { $in.$PropertyName } } $DotMethod = { $in.$MethodName($MethodArguments) } } process { # Create a collection for the entire chain of operations and their arguments. $DotChain = @() $DotArgsAst = @() $DotChainPart = '' $DotChainPattern = '^\.\p{L}' $targetCommandAst = $CommandAst $commandSequence = @() $lastCommandAst = $null # Then, walk over each element of the commands $CommandElements = @(do { $lastCommandAst = $targetCommandAst $commandSequence += $targetCommandAst $targetCommandAst.CommandElements # If the grandparent didn't have a list of statements, this is the only dot sequence in the chain. if (-not $CommandAst.Parent.Parent.Statements) { break } $nextStatementIndex = $commandAst.Parent.Parent.Statements.IndexOf($targetCommandAst.Parent) + 1 $nextStatement = $CommandAst.Parent.Parent.Statements[$nextStatementIndex] if ($nextStatement -isnot [Management.Automation.Language.PipelineAst]) { break } if ($nextStatement.PipelineElements[0] -isnot [Management.Automation.Language.CommandAst]) { break } if ($nextStatement.PipelineElements[0].CommandElements[0].Value -notmatch $DotChainPattern) { break } $targetCommandAst = $CommandAst.Parent.Parent.Statements[$nextStatementIndex].PipelineElements[0] } while ($targetCommandAst)) for ( $elementIndex =0 ; $elementIndex -lt $CommandElements.Count; $elementIndex++) { # If we are on the first element, or the command element starts with the DotChainPattern if ($elementIndex -eq 0 -or $CommandElements[$elementIndex].Value -match $DotChainPattern) { if ($DotChainPart) { $DotChain += [PSCustomObject]@{ PSTypeName = 'PipeScript.Dot.Chain' Name = $DotChainPart Arguments = $DotArgsAst } } $DotArgsAst = @() # A given step started with dots can have more than one step in the chain specified. $elementDotChain = $CommandElements[$elementIndex].Value.Split('.') [Array]::Reverse($elementDotChain) $LastElement, $otherElements = $elementDotChain if ($otherElements) { foreach ($element in $otherElements) { $DotChain += [PSCustomObject]@{ PSTypeName = 'PipeScript.Dot.Chain' Name = $element Arguments = @() } } } $DotChainPart = $LastElement } # If we are not on the first index or the element does not start with a dot, it is an argument. else { $DotArgsAst += $CommandElements[$elementIndex] } } if ($DotChainPart) { $DotChain += [PSCustomObject]@{ PSTypeName = 'PipeScript.Dot.Chain' Name = $DotChainPart Arguments = $DotArgsAst } } $NewScript = @() $indent = 0 $WasPipedTo = $CommandAst.IsPipedTo # By default, we are not creating a property bag. # This default will change if: # * More than one property is defined # * A property is explicitly assigned $isPropertyBag = $false # If we were piped to, adjust indent (for now) if ($WasPipedTo) { $indent += 4 } # Declare the start of the chain (even if we don't use it) $propertyBagStart = (' ' * $indent) + '[PSCustomObject][Ordered]@{' # and keep track of all items we must post process. $PostProcess = @() # If more than one item was in the chain if ($DotChain.Length -ge 0) { $indent += 4 # adjust indentation } # Walk thru all items in the chain of properties. foreach ($Dot in $DotChain) { $firstDotArg, $secondDotArg, $restDotArgs = $dot.Arguments # Determine what will be the segment of the dot chain. $thisSegement = # If the dot chain has no arguments, treat it as a property if (-not $dot.Arguments) { $DotProperty -replace '\$PropertyName', "'$($dot.Name)'" } # If the dot chain's first argument is an assignment elseif ($firstDotArg -is [Management.Automation.Language.StringConstantExpressionAst] -and $firstDotArg.Value -eq '=') { $isPropertyBag = $true # and the second is a script block if ($secondDotArg -is [Management.Automation.Language.ScriptBlockExpressionAst]) { # it will become either a [ScriptMethod] or [ScriptProperty] $secondScriptBlock = [ScriptBlock]::Create( $secondDotArg.Extent.ToString() -replace '^\{' -replace '\}$' ) # If the script block had parameters (even if they were empty parameters) # It should become a ScriptMethod if ($secondScriptBlock.Ast.ParamBlock) { "[PSScriptMethod]::New('$($dot.Name)', $secondDotArg)" } else { # Otherwise, it will become a ScriptProperty "[PSScriptProperty]::New('$($dot.Name)', $secondDotArg)" } $PostProcess += $dot.Name } # If we had an array of arguments, and both elements were ScriptBlocks elseif ($secondDotArg -is [Management.Automation.Language.ArrayLiteralAst] -and $secondDotArg.Elements.Count -eq 2 -and $secondDotArg.Elements[0] -is [Management.Automation.Language.ScriptBlockExpressionAst] -and $secondDotArg.Elements[1] -is [Management.Automation.Language.ScriptBlockExpressionAst] ) { # Then we will treat this as a settable script block $PostProcess += $dot.Name "[PSScriptProperty]::New('$($dot.Name)', $($secondDotArg.Elements[0]), $($secondDotArg.Elements[1]))" } elseif (-not $restDotArgs) { # Otherwise, if we only have one argument, use the expression directly $secondDotArg.Extent.ToString() } elseif ($restDotArgs) { # Otherwise, if we had multiple values, create a list. @( $secondDotArg.Extent.ToString() foreach ($otherDotArg in $restDotArgs) { $otherDotArg.Extent.Tostring() } ) -join ',' } } # If the dot chain's first argument is a ScriptBlock elseif ($firstDotArg -is [Management.Automation.Language.ScriptBlockExpressionAst]) { # Run that script block "& $($firstDotArg.Extent.ToString())" } elseif ($firstDotArg -is [Management.Automation.Language.ParenExpressionAst]) { # If the first argument is a parenthesis, assume the contents to be method arguments $DotMethod -replace '\$MethodName', $dot.Name -replace '\(\$MethodArguments\)',$firstDotArg.ToString() } else { # If the first argument is anything else, assume all remaining arguments to be method parameters. $DotMethod -replace '\$MethodName', $dot.Name -replace '\(\$MethodArguments\)',( '(' + ($dot.Arguments -join ',') + ')' ) } # Now we add the segment to the total script $NewScript += if (-not $isPropertyBag -and $DotChain.Length -eq 1 -and $thisSegement -notmatch '^\[PS') { # If the dot chain is a single item, and not part of a property bag, include it directly "$(' ' * ($indent - 4))$thisSegement" } else { $isPropertyBag = $true # Otherwise include this segment as a hashtable assignment with the correct indentation. $thisSegement = @($thisSegement -split '[\r\n]+' -ne '' -replace '$', (' ' * 8)) -join [Environment]::NewLine @" $(' ' * $indent)'$($dot.Name.Replace("'","''"))' = $(' ' * ($indent + 4))$thisSegement "@ } } # If we were generating a property bag if ($isPropertyBag) { if ($WasPipedTo) { # and it was piped to # Add the start of the pipeline and the property bag start to the top of the script. $NewScript = @('& { process {') + ((' ' * $indent) + '$in = $this = $_') + $propertyBagStart + $NewScript } else { # If it was not piped to, just add the start of the property bag $newScript = @($propertyBagStart) + $NewScript } } elseif ($WasPipedTo) { # If we were piped to (but were not a property bag) $indent -= 4 # add the start of the pipeline to the top of the script. $newScript = @('& { process {') + ((' ' * $indent) + '$in = $this = $_') + $NewScript } # If we were a property bag if ($isPropertyBag) { # close out the script $NewScript += ($(' ' * $indent) + '}') $indent -= 4 } # If there was post processing if ($PostProcess) { # Change the property bag start to assign it to a variable $NewScript = $newScript -replace ($propertyBagStart -replace '\W', '\$0'), "`$Out = $propertyBagStart" foreach ($post in $PostProcess) { # and change any [PSScriptProperty] or [PSScriptMethod] into a method on that object. $newScript += "`$Out.PSObject.Members.Add(`$out.$Post)" } # Then output. $NewScript += '$Out' } # If we were piped to if ($WasPipedTo) { # close off the script. $NewScript += '} }' } else { # otherwise, make it a subexpression $NewScript = '$(' + ($NewScript -join [Environment]::NewLine) + ')' } $NewScript = $NewScript -join [Environment]::Newline # Return the created script. $newScriptBlock = [scriptblock]::Create($NewScript) if ($targetCommandAst -ne $CommandAst) { $newScriptBlock | Add-Member NoteProperty SkipUntil $commandSequence } $newScriptBlock } |