parser: minor allocations reductions

lib/protoboeuf/parser.rb

@@ -27,9 +27,9 @@ def initialize(file_name, line_no, col_no)
 
     def to_s
       if @file_name
-        @file_name + "@" + @line_no.to_s + ":" + @col_no.to_s
+        "#{@file_name}@#{@line_no}:#{@col_no}"
       else
-        @line_no.to_s + ":" + @col_no.to_s
+        "#{@line_no}:#{@col_no}"
       end
     end
   end
@@ -42,7 +42,7 @@ def initialize(msg, pos)
     end
 
     def to_s
-      @msg.to_s + "@" + @pos.to_s
+      "#{@msg}@#{@pos}"
     end
   end
 
@@ -200,10 +200,9 @@ def self.check_enum_collision(enums)
     names = Set.new
     enums.each do |enum|
       enum.constants.each do |const|
-        if names.include? const.name
+        unless names.add? const.name
           raise ParseError.new("duplicate enum constant name #{const.name}", const.pos)
         end
-        names.add(const.name)
       end
     end
   end
@@ -294,33 +293,25 @@ def self.parse_field_type(input)
     end
 
     type_name = ident
-    loop do
-      if input.match '.'
-        type_name += '.' + input.read_ident
-      else
-        break
-      end
+    while input.match '.'
+      type_name << '.' << input.read_ident
     end
 
     type_name
   end
 
   # Parse a package name, e.g. foo.bar.bif
   def self.parse_package_name(input)
-    name = ""
+    name = +""
 
     if input.match '.'
-      name += '.' + input.read_ident
+      name << '.' << input.read_ident
     else
-      name += input.read_ident
+      name << input.read_ident
     end
 
-    loop do
-      if input.match '.'
-        name += '.' + input.read_ident
-      else
-        break
-      end
+    while input.match '.'
+      name << '.' << input.read_ident
     end
 
     name
@@ -387,11 +378,7 @@ def self.parse_body(input, pos, inside_message)
 
     input.expect '{'
 
-    loop do
-      if input.match '}'
-        break
-      end
-
+    until input.match '}'
       # Nested/local message and enum definitions
       if inside_message && (input.match 'message')
         msg_pos = input.pos
@@ -525,11 +512,7 @@ def self.parse_enum(input, pos)
     enum_name = input.read_ident
     input.expect '{'
 
-    loop do
-      if input.match '}'
-        break
-      end
-
+    until input.match '}'
       if input.match 'option'
         input.eat_ws
         option_name = input.read_ident
@@ -553,7 +536,7 @@ def self.parse_enum(input, pos)
         raise ParseError.new("enum constants should be uppercase identifiers", const_pos)
       end
 
-      if constants.size == 0 && number != 0
+      if constants.empty? && number != 0
         raise ParseError.new("the first enum constant should always have value 0", const_pos)
       end
 
@@ -664,12 +647,8 @@ def eat_ch()
     end
 
     # Consume whitespace
-    def eat_ws()
-      loop do
-        if eof?
-          break
-        end
-
+    def eat_ws
+      until eof?
         # Single-line comment
         if match_exact("//")
           loop do
@@ -721,11 +700,7 @@ def eat_ws()
     def read_ident
       name = +''
 
-      loop do
-        if eof?
-          break
-        end
-
+      until eof?
         ch = peek_ch
 
         if !ch.match(/[A-Za-z0-9_]/)
@@ -735,7 +710,7 @@ def read_ident
         name << eat_ch
       end
 
-      if name.size == 0
+      if name.empty?
         raise ParseError.new("expected identifier", pos)
       end
 
@@ -809,11 +784,7 @@ def read_int
       end
 
       # For each digit
-      loop do
-        if eof?
-          break
-        end
-
+      until eof?
         ch = peek_ch
 
         if ch >= '0' && ch <= '9'