Support special escape sequences in Terraform (rouge-ruby#2073)

Author: tancnle

lib/rouge/lexers/terraform.rb

@@ -39,8 +39,9 @@ def self.builtins
 
       state :strings do
         rule %r/\\./, Str::Escape
+        rule %r/(\$[\$]+|%[%]+)(\{)/, Str
         rule %r/\$\{/ do
-          token Keyword
+          token Punctuation
           push :interpolation
         end
       end
@@ -66,7 +67,7 @@ def self.builtins
 
       state :interpolation do
         rule %r/\}/ do
-          token Keyword
+          token Punctuation
           pop!
         end
 

spec/visual/samples/terraform

@@ -84,3 +84,18 @@ resource "aws_subnet" "main" {
 resource "aws_cloudfront_distribution" "s3_distribution" {
   aliases = ["www.${replace(var.domain_name, "/\\.$/", "")}"]
 }
+
+# Directives in string templates
+locals {
+  policy = <<EOT
+%{ for ip in aws_instance.example[*].private_ip }
+server ${ip}
+%{ endfor }
+EOT
+}
+
+# Special escape sequences that do not use backslashes
+locals {
+  demo_dollars_1 = "$${local.demo}"
+  demo_dollars_2 = "%%{for i in items}"
+}