1 files changed, 33 insertions, 15 deletions

diff --git a/ext/ripper/tools/dsl.rb b/ext/ripper/tools/dsl.rb
index 49ff51711f..d0002d1ec3 100644
--- a/ext/ripper/tools/dsl.rb
+++ b/ext/ripper/tools/dsl.rb
@@ -1,37 +1,52 @@
+# frozen_string_literal: true
+
 # Simple DSL implementation for Ripper code generation
 #
-# input: /*% ripper: stmts_add(stmts_new, void_stmt) %*/
+# input: /*% ripper: stmts_add!(stmts_new!, void_stmt!) %*/
 # output:
 #   VALUE v1, v2;
 #   v1 = dispatch0(stmts_new);
 #   v2 = dispatch0(void_stmt);
 #   $$ = dispatch2(stmts_add, v1, v2);
-
-$dollar = "$$"
-alias $$ $dollar
+#
+# - The code must be a single line.
+#
+# - The code is basically Ruby code, even if it appears like in C and
+#   the result will be processed as C. e.g., comments need to be in
+#   Ruby style.
 
 class DSL
-  def initialize(code, options)
+  TAG_PATTERN = /(?><[a-zA-Z0-9_]+>)/.source
+  NAME_PATTERN = /(?>\$|\d+|[a-zA-Z_][a-zA-Z0-9_]*|\[[a-zA-Z_.][-a-zA-Z0-9_.]*\])(?>(?:\.|->)[a-zA-Z_][a-zA-Z0-9_]*)*/.source
+  NOT_REF_PATTERN = /(?>\#.*|[^\"$@]*|"(?>\\.|[^\"])*")/.source
+
+  def self.line?(line, lineno = nil)
+    if %r</\*% *ripper(?:\[(.*?)\])?: *(.*?) *%\*/> =~ line
+      new($2, $1&.split(",") || [], lineno)
+    end
+  end
+
+  def initialize(code, options, lineno = nil)
+    @lineno = lineno
     @events = {}
     @error = options.include?("error")
     @brace = options.include?("brace")
     if options.include?("final")
       @final = "p->result"
     else
-      @final = (options.grep(/\A\$(?:\$|\d+)\z/)[0] || "$$")
+      @final = (options.grep(/\A\$#{NAME_PATTERN}\z/o)[0] || "p->s_lvalue")
     end
     @vars = 0
 
-    # create $1 == "$1", $2 == "$2", ...
-    s = (1..20).map {|n| "$#{n}"}
-    re = Array.new(s.size, "([^\0]+)")
-    /#{re.join("\0")}/ =~ s.join("\0")
-
     # struct parser_params *p
     p = p = "p"
 
-    @code = ""
+    @code = +""
+    code = code.gsub(%r[\G#{NOT_REF_PATTERN}\K(\$|\$:|@)#{TAG_PATTERN}?#{NAME_PATTERN}]o, '"\&"')
     @last_value = eval(code)
+  rescue SyntaxError
+    $stderr.puts "error on line #{@lineno}" if @lineno
+    raise
   end
 
   attr_reader :events
@@ -62,11 +77,15 @@ class DSL
     vars = []
     args.each do |arg|
       vars << v = new_var
-      @code << "#{ v }=#{ arg };"
+      if arg =~ /\A\$:#{NAME_PATTERN}\z/
+        @code << "#{ v }=get_value(#{arg});"
+      else
+        @code << "#{ v }=#{ arg };"
+      end
     end
     v = new_var
     d = "dispatch#{ args.size }(#{ [event, *vars].join(",") })"
-    d = "#{ vars.last }==Qundef ? #{ vars.first } : #{ d }" if qundef_check
+    d = "#{ vars.last }==rb_ripper_none ? #{ vars.first } : #{ d }" if qundef_check
     @code << "#{ v }=#{ d };"
     v
   end
@@ -85,4 +104,3 @@ class DSL
     name
   end
 end
-