Fix incorrectly setting end range to 1

When passing a single Line/Column value, we now assume you want a zero
length extent of a single point. This was already the case for buffer
ranges.

Also take a pass at style because it was an abomination and I apologize
to the world for doing it.

Author: SeeminglyScience

module/PowerShellEditorServices/Commands/Public/ConvertTo-ScriptExtent.ps1

@@ -8,77 +8,63 @@ function ConvertTo-ScriptExtent {
     [CmdletBinding()]
     [OutputType([System.Management.Automation.Language.IScriptExtent])]
     param(
-        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ParameterSetName='ByOffset')]
+        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ParameterSetName = 'ByOffset')]
         [Alias('StartOffset', 'Offset')]
-        [int]
-        $StartOffsetNumber,
+        [int] $StartOffsetNumber,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByOffset')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByOffset')]
         [Alias('EndOffset')]
-        [int]
-        $EndOffsetNumber,
+        [int] $EndOffsetNumber,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByPosition')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByPosition')]
         [Alias('StartLine', 'Line')]
-        [int]
-        $StartLineNumber,
+        [int] $StartLineNumber,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByPosition')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByPosition')]
         [Alias('StartColumn', 'Column')]
-        [int]
-        $StartColumnNumber,
+        [int] $StartColumnNumber,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByPosition')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByPosition')]
         [Alias('EndLine')]
-        [int]
-        $EndLineNumber,
+        [int] $EndLineNumber,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByPosition')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByPosition')]
         [Alias('EndColumn')]
-        [int]
-        $EndColumnNumber,
+        [int] $EndColumnNumber,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByPosition')]
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByOffset')]
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByBuffer')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByPosition')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByOffset')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByBuffer')]
         [Alias('File', 'FileName')]
-        [string]
-        $FilePath = $psEditor.GetEditorContext().CurrentFile.Path,
+        [string] $FilePath = $psEditor.GetEditorContext().CurrentFile.Path,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByBuffer')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByBuffer')]
         [Alias('Start')]
-        [Microsoft.PowerShell.EditorServices.Extensions.IFilePosition, Microsoft.PowerShell.EditorServices]
-        $StartBuffer,
+        [Microsoft.PowerShell.EditorServices.Extensions.IFilePosition, Microsoft.PowerShell.EditorServices] $StartBuffer,
 
-        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName='ByBuffer')]
+        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = 'ByBuffer')]
         [Alias('End')]
-        [Microsoft.PowerShell.EditorServices.Extensions.IFilePosition, Microsoft.PowerShell.EditorServices]
-        $EndBuffer,
-
-        [Parameter(Mandatory,
-                   ValueFromPipeline,
-                   ValueFromPipelineByPropertyName,
-                   ParameterSetName='ByExtent')]
-        [System.Management.Automation.Language.IScriptExtent]
-        $Extent
+        [Microsoft.PowerShell.EditorServices.Extensions.IFilePosition, Microsoft.PowerShell.EditorServices] $EndBuffer,
+
+        [Parameter(Mandatory, ValueFromPipeline, ValueFromPipelineByPropertyName, ParameterSetName = 'ByExtent')]
+        [System.Management.Automation.Language.IScriptExtent] $Extent
     )
     begin {
         $fileContext = $psEditor.GetEditorContext().CurrentFile
         $emptyExtent = [Microsoft.PowerShell.EditorServices.Extensions.FileScriptExtent, Microsoft.PowerShell.EditorServices]::Empty
     }
-
     process {
         # Already a InternalScriptExtent, FileScriptExtent or is empty.
         $returnAsIs = $Extent -and
-                     (0 -ne $Extent.StartOffset   -or
-                      0 -ne $Extent.EndOffset     -or
-                      $Extent -eq $emptyExtent)
+            ($Extent.StartOffset -or $Extent.EndOffset -or $Extent -eq $emptyExtent)
 
-        if ($returnAsIs) { return $Extent }
+        if ($returnAsIs) {
+            return $Extent
+        }
 
         if ($StartOffsetNumber) {
             $startOffset = $StartOffsetNumber
-            $endOffset   = $EndOffsetNumber
+            $endOffset = $EndOffsetNumber
 
             # Allow creating a single position extent with just the offset parameter.
             if (-not $EndOffsetNumber) {
@@ -92,8 +78,7 @@ function ConvertTo-ScriptExtent {
         }
 
         if ($StartBuffer) {
-            if (-not $EndBuffer)
-            {
+            if (-not $EndBuffer) {
                 $EndBuffer = $StartBuffer
             }
 
@@ -105,10 +90,31 @@ function ConvertTo-ScriptExtent {
                 $EndBuffer.Column)
         }
 
-        if (-not $StartColumnNumber) { $StartColumnNumber = 1 }
-        if (-not $StartLineNumber)   { $StartLineNumber   = 1 }
-        if (-not $EndLineNumber)     { $EndLineNumber     = 1 }
-        if (-not $EndColumnNumber)   { $EndColumnNumber   = 1 }
+        # Allow piping a single line and column to get a zero length script extent.
+        if ($PSBoundParameters.ContainsKey('StartColumnNumber') -and -not $PSBoundParameters.ContainsKey('EndColumnNumber')) {
+            $EndColumnNumber = $StartColumnNumber
+        }
+
+        if ($PSBoundParameters.ContainsKey('StartLineNumber') -and -not $PSBoundParameters.ContainsKey('EndLineNumber')) {
+            $EndLineNumber = $StartLineNumber
+        }
+
+        # Protect against zero as a value since lines and columns start at 1
+        if (-not $StartColumnNumber) {
+            $StartColumnNumber = 1
+        }
+
+        if (-not $StartLineNumber) {
+            $StartLineNumber = 1
+        }
+
+        if (-not $EndLineNumber) {
+            $EndLineNumber = 1
+        }
+
+        if (-not $EndColumnNumber) {
+            $EndColumnNumber = 1
+        }
 
         return [Microsoft.PowerShell.EditorServices.Extensions.FileScriptExtent, Microsoft.PowerShell.EditorServices]::FromPositions(
             $fileContext,