Merge pull request #24 from jfhbrook/windows

PowerShell port of install.sh

README.org

@@ -104,6 +104,28 @@ By symlinking you can easily update Chemacs with a =git pull=. Chemacs is not
 available on ELPA/MELPA because its special position in the Emacs boot process
 would cause a chicken and egg problem.
 
+There's a similar script for Windows called =install.sh=.
+
+#+BEGIN_SRC powershell
+$ git clone https://github.com/plexus/chemacs.git
+$ cd chemacs
+$ .\install.ps1
+OK copying file to ~/.emacs
+#+END_SRC
+
+The Windows script copies the ~/.emacs file rather than symlinking it, as
+symlinks in Windows require elevated privileges. To update the file, run
+=install.ps1= a second time, if necessary - it uses hashing to detect
+changes and prompts for conformation before overwriting
+
+#+BEGIN_SRC powershell
+$ .\install.ps1
+WARN content is different between C:\Users\Me\.emacs and C:\Users\Me\repos\chemacs\.emacs
+WARN chemacs may already be installed OR something else may be in the way
+Do you want to overwrite C:\Users\Me\.emacs?: y
+OK updated chemacs files successfully.
+#+END_SRC
+
 ** Usage
 
 Chemacs adds an extra command line option to Emacs, =--with-profile=. Profiles

install.ps1

@@ -0,0 +1,57 @@
+param(
+    [switch] $Confirm = $True
+)
+
+$ErrorActionPreference = "Stop"
+
+$ChemacsPath = Join-Path (Split-Path $PSCommandPath) ".emacs"
+
+Try {
+  Set-Variable -Scope global EmacsPath $(
+    Join-Path $(Get-Variable -Scope global HOME).Value ".emacs"
+  )
+
+} Catch {
+  # If $HOME hasn't been defined by the user, then emacs will default to this
+  # directory on modern versions of Windows. Older versions of Windows probably
+  # don't even have PowerShell installed, so I make no effort to support them.
+  Set-Variable -Scope global EmacsPath $(
+    Resolve-Path "~/AppData/roaming/.emacs"
+  )
+}
+
+If (-Not (Test-Path -Path $EmacsPath)) {
+    # In Windows, symlinks require admin privileges, so we copy the
+    # file wholesale instead.
+    Write-Host "OK copying file to ~/.emacs..."
+
+    Copy-Item $ChemacsPath $EmacsPath
+} Else {
+    # Because we copied the file instead of symlinking it, we have to try to
+    # detect changes with hashing instead...
+    If ((Get-FileHash $ChemacsPath).Hash -Eq (Get-FileHash $EmacsPath).Hash) {
+        Write-Host "OK chemacs appears to already be copied over, you're all good."
+    } Else {
+        Write-Host ("WARN content is different between {0} and {1}" -f @($EmacsPath, $ChemacsPath))
+        
+        $should_write = $False
+
+        If ($Confirm) {
+            Write-Host "WARN chemacs may already be installed OR something else may be in the way"
+            $ans = Read-Host ("Do you want to overwrite {0}?" -f $EmacsPath)
+
+            If (@("y", "yes", "Y", "YES").Contains($ans)) {
+                $should_write = $True
+            }
+        } Else {
+            $should_write = $True
+        }
+
+        If ($should_write) {
+            Copy-Item $ChemacsPath $EmacsPath
+            Write-Host "OK updated chemacs files successfully."
+        } Else {
+            Write-Host "WARN took no action."
+        }
+    }
+}