enhancement: git blame input (Fixes #199)

Extensions/Git.Blame.Input.ugit.extension.ps1

@@ -0,0 +1,50 @@
+<#
+.SYNOPSIS
+    Extends git blame's parameters
+.DESCRIPTION
+    Extends the parameters for git blame.
+#>
+[ValidatePattern('^git blame')]
+[Management.Automation.Cmdlet("Use","Git")]
+[CmdletBinding(PositionalBinding=$false)]
+param(
+# The line number (and relative offset)
+[Parameter(ValueFromPipelineByPropertyName)]
+[int[]]
+$LineNumber,
+
+# The blame pattern to look for.
+[Parameter(ValueFromPipelineByPropertyName)]
+[string[]]
+$Pattern
+)
+
+process {
+
+    # All git of these git blame parameters need to be after the input object:
+    foreach ($gitArgToBe in @(
+            if ($LineNumber) { # If a -LineNumber was provided
+                # turn each pair into a range
+                for ($LineNumberNumber = 0; $LineNumberNumber -lt $LineNumber.Length; $LineNumberNumber++) {                    
+                    "-L" # (this will be specified by git blame's real parameter, '-L')
+                    "$(
+                        if ($LineNumberNumber -lt ($LineNumber.Length - 1)) {                            
+                            "$($lineNumber[$LineNumberNumber]),$($lineNumber[$LineNumberNumber + 1])"       
+                        } else {
+                            # if there was only one of a pair, only grab that line.
+                            "$($lineNumber[$LineNumberNumber]),1"
+                        }
+                    )"
+                }
+            }
+
+            if ($Pattern) { # If a -Pattern was provided
+                foreach ($linePattern in $pattern) {
+                    "-L" # this also becomes '-L' in git blame
+                    "$linePattern"
+                }
+            }
+    )) {    
+        $gitArgToBe | Add-Member NoteProperty AfterInput $true -Force -PassThru
+    }
+}