Transpilers/Syntax/SwitchAsIs.psx.ps1
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<# .SYNOPSIS Switches based off of type, using as or is .DESCRIPTION Slightly rewrites a switch statement that is written with full typenames. Normally, PowerShell would try to match the typename as a literal string, which is highly unlikely to work. SwitchAsIs will take a switch statement in the form of: ~~~PowerShell switch ($t) { [typeName] { } } ~~~ And rewrite it to use the casting operators If the label matches As or Is, it will use the corresponding operators. #> [ValidateScript({ $validating = $_ if ($validating -isnot [Management.Automation.Language.SwitchStatementAst]) { return $false } $hasTypeKeys = $validating.Clauses.Item1 -match '^\s{0,}\[' -and $validating.Clauses.Item1 -match '\]\s{0,}$' if ($hasTypeKeys -and $validating.Flags -notmatch 'Regex') { return $true } if ($validating.Label -match '^[ai]s') { return $true } return $false })] param( # The switch statement [Parameter(ValueFromPipeline)] [Management.Automation.Language.SwitchStatementAst] $SwitchStatementAst ) process { [scriptblock]::Create( @("switch ($($SwitchStatementAst.Condition)) {" foreach ($clause in $SwitchStatementAst.Clauses) { if ($clause.Item1 -match '^\s{0,}\[' -and $clause.Item1 -match '\]\s{0,}$') { if ($SwitchStatementAst.Label -match 'as') { "{`$_ -as $($clause.Item1)}" } else { "{`$_ -is $($clause.Item1)}" } $clause.Item2.ToString() } else { $clause.Item1 $clause.Item2.ToString() } } "}") -join [Environment]::newLine ) } |