diff --git a/script/add-grammar b/script/add-grammar
index 584b9cdf..779dd62b 100755
--- a/script/add-grammar
+++ b/script/add-grammar
@@ -7,43 +7,42 @@ ROOT = File.expand_path("../../", __FILE__)
 
 # Break a repository URL into its separate components
 def parse_url(input)
-	hosts = "github\.com|bitbucket\.org|gitlab\.com"
-	
-	# HTTPS/HTTP link pointing to recognised hosts
-	if input =~ /^(?:https?:\/\/)?(?:[^.@]+@)?(?:www\.)?(#{hosts})\/([^\/]+)\/([^\/]+)/i
-		{ host: $1.downcase(), user: $2, repo: $3.sub(/\.git$/, "") }
-	# SSH
-	elsif input =~ /^git@(#{hosts}):([^\/]+)\/([^\/]+)\.git$/i
-		{ host: $1.downcase(), user: $2, repo: $3 }
-	# provider:user/repo
-	elsif input =~ /^(github|bitbucket|gitlab):\/?([^\/]+)\/([^\/]+)\/?$/i
-		{ host: $1.downcase(), user: $2, repo: $3 }
-	# user/repo - Common GitHub shorthand
-	elsif input =~ /^\/?([^\/]+)\/([^\/]+)\/?$/
-		{ host: "github.com", user: $1, repo: $2 }
-	else
-		raise "Unsupported URL: #{input}"
-	end
+  hosts = "github\.com|bitbucket\.org|gitlab\.com"
+  
+  # HTTPS/HTTP link pointing to recognised hosts
+  if input =~ /^(?:https?:\/\/)?(?:[^.@]+@)?(?:www\.)?(#{hosts})\/([^\/]+)\/([^\/]+)/i
+    { host: $1.downcase(), user: $2, repo: $3.sub(/\.git$/, "") }
+  # SSH
+  elsif input =~ /^git@(#{hosts}):([^\/]+)\/([^\/]+)\.git$/i
+    { host: $1.downcase(), user: $2, repo: $3 }
+  # provider:user/repo
+  elsif input =~ /^(github|bitbucket|gitlab):\/?([^\/]+)\/([^\/]+)\/?$/i
+    { host: $1.downcase(), user: $2, repo: $3 }
+  # user/repo - Common GitHub shorthand
+  elsif input =~ /^\/?([^\/]+)\/([^\/]+)\/?$/
+    { host: "github.com", user: $1, repo: $2 }
+  else
+    raise "Unsupported URL: #{input}"
+  end
 end
 
 # Isolate the vendor-name component of a submodule path
 def parse_submodule(name)
-	name =~ /^(?:.*(?:vendor\/)?grammars\/)?([^\/]+)/i
-	path = "vendor/grammars/#{$1}"
-	unless File.exist?("#{ROOT}/" + path)
-		warn "Submodule '#{path}' does not exist. Aborting."
-		exit 1
-	end
-	path
+  name =~ /^(?:.*(?:vendor\/)?grammars\/)?([^\/]+)/i
+  path = "vendor/grammars/#{$1}"
+  unless File.exist?("#{ROOT}/" + path)
+    warn "Submodule '#{path}' does not exist. Aborting."
+    exit 1
+  end
+  path
 end
 
 # Print debugging feedback to STDOUT if running with --verbose
 def log(msg)
-	puts msg if $verbose
+  puts msg if $verbose
 end
 
 
-
 usage = """Usage:
   #{$0} [--replace grammar] url
 Examples:
@@ -55,13 +54,13 @@ $replace = nil
 $verbose = false
 
 OptionParser.new do |opts|
-	opts.banner = usage
-	opts.on("-v", "--verbose", "Print verbose feedback to STDOUT") do
-		$verbose = true
-	end
-	opts.on("-rSUBMODULE", "--replace=SUBMODDULE", "Replace an existing grammar submodule.") do |name|
-		$replace = name
-	end
+  opts.banner = usage
+  opts.on("-v", "--verbose", "Print verbose feedback to STDOUT") do
+    $verbose = true
+  end
+  opts.on("-rSUBMODULE", "--replace=SUBMODDULE", "Replace an existing grammar submodule.") do |name|
+    $replace = name
+  end
 end.parse!
 
 
@@ -69,8 +68,8 @@ $url = ARGV[0]
 
 # No URL? Print a usage message and bail.
 unless $url
-	warn usage
-	exit 1;
+  warn usage
+  exit 1;
 end
 
 # Ensure the given URL is an HTTPS link
@@ -80,9 +79,9 @@ repo_new = "vendor/grammars/#{parts[:repo]}"
 repo_old = parse_submodule($replace) if $replace
 
 if repo_old
-	log "Deregistering: #{repo_old}"
-	`git submodule deinit #{repo_old}`
-	`git rm -rf #{repo_old}`
+  log "Deregistering: #{repo_old}"
+  `git submodule deinit #{repo_old}`
+  `git rm -rf #{repo_old}`
 end
 
 log "Registering new submodule: #{repo_new}"