From 9f568d9a82b2df68c814a0830ba725f563477a3b Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sat, 21 Apr 2012 22:47:39 +0200
Subject: [PATCH 01/14] Add Lua scanner

---
 lib/coderay/scanners/lua.rb | 137 ++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 lib/coderay/scanners/lua.rb

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
new file mode 100644
index 00000000..2540a2fa
--- /dev/null
+++ b/lib/coderay/scanners/lua.rb
@@ -0,0 +1,137 @@
+# -*- coding: utf-8 -*-
+
+# http://www.lua.org/manual/5.2/manual.html
+class CodeRay::Scanners::Lua < CodeRay::Scanners::Scanner
+
+  register_for :lua
+  file_extension "lua"
+  title "Lua"
+
+  KEYWORDS = %w[and break do else elseif end
+  for function goto if in
+  local not or repeat return
+  then until while
+  ]
+
+  PREDEFINED_CONSTANTS = %w[false true nil]
+
+  IDENT_KIND = CodeRay::WordList.new(:ident)
+    .add(KEYWORDS, :keyword)
+    .add(PREDEFINED_CONSTANTS, :predefined_constant)
+
+  protected
+
+  def setup
+    @state = :initial
+  end
+
+  def scan_tokens(encoder, options)
+    @encoder = encoder
+    @options = options
+
+    send(:"handle_state_#@state") until eos?
+
+
+    @encoder
+  end
+
+  def handle_state_initial
+    if match = scan(/\-\-\[\=*\[/)   #--[[ long (possibly multiline) comment ]]
+      @num_equals = match.count("=") # Number must match for comment end
+      @encoder.begin_group(:comment)
+      @encoder.text_token(match, :delimiter)
+      @state = :long_comment
+    elsif match = scan(/--.*?$/) # --Lua comment
+      @encoder.text_token(match, :comment)
+    elsif match = scan(/\[=*\[/)     # [[ long (possibly multiline) string ]]
+      @num_equals = match.count("=") # Number must match for comment end
+      @encoder.begin_group(:string)
+      @encoder.text_token(match, :delimiter)
+      @state = :long_string
+    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\{\}\[\]:;,] | \.(?!\d)/x)
+      @encoder.text_token(match, :operator)
+    elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # Normal letters (or letters followed by digits)
+      kind = IDENT_KIND[match]
+
+      if kind == :keyword and match == "function"
+        @state = :function_expected
+      end
+
+      @encoder.text_token(match, kind)
+    elsif match = scan(/["']/)
+      @encoder.begin_group(:string)
+      @encoder.text_token(match, :delimiter)
+      @start_delim = match
+      @state = :string                            # hex number ←|→ decimal number
+    elsif match = scan(/0x(?:[0-9a-z])* \. [0-9a-z]+ (?:p-\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
+      @encoder.text_token(match, :float) # hex | decimal
+    elsif match = scan(/0x[0-9a-z]+ (?:p-\d+)? | \d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
+      @encoder.text_token(match, :integer)
+    elsif match = scan(/\s+/)
+      @encoder.text_token(match, :space)
+    else
+      @encoder.text_token(getch, :error)
+    end
+  end
+
+  def handle_state_function_expected
+    if match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* \./x) # function tbl.subtbl.foo()
+      @encoder.text_token(match, :ident)
+    elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # function foo()
+      @encoder.text_token(match, :function)
+      @state = :initial
+    elsif match = scan(/\s+/) # Between the function keyword and the ident may be any amount of whitespace
+      @encoder.text_token(match, :space)
+    else
+      @encoder.text_token(getch, :error)
+      @state = :initial
+    end
+  end
+
+  def handle_state_long_comment
+    if match = scan(/.*?(?=\]={#@num_equals}\])/m)
+      @encoder.text_token(match, :content)
+
+      delim = scan(/\]={#@num_equals}\]/)
+      @encoder.text_token(delim, :delimiter)
+    else # No terminator found till EOF
+      @encoder.text_token(rest, :error)
+      terminate
+    end
+    @encoder.end_group(:comment)
+    @state = :initial
+  end
+
+  def handle_state_long_string
+    if match = scan(/.*?(?=\]={#@num_equals}\])/m) # Long strings do not interpret any escape sequences
+      @encoder.text_token(match, :content)
+
+      delim = scan(/\]={#@num_equals}\]/)
+      @encoder.text_token(delim, :delimiter)
+    else # No terminator found till EOF
+      @encoder.text_token(rest, :error)
+      terminate
+    end
+    @encoder.end_group(:string)
+    @state = :initial
+  end
+
+  def handle_state_string
+    if match = scan(/[^\\#@start_delim\n]+/) # Everything except \ and the start delimiter character is string content (newlines are only allowed if preceeded by \ or \z)
+      @encoder.text_token(match, :content)
+    elsif match = scan(/\\(?:['"abfnrtv\\]|z\s*|x\h\h|\d{1,3}|\n)/m)
+      @encoder.text_token(match, :char)
+    elsif match = scan(Regexp.compile(@start_delim))
+      @encoder.text_token(match, :delimiter)
+      @encoder.end_group(:string)
+      @state = :initial
+    elsif match = scan(/\n/) # Lua forbids unescaped newlines in normal non-long strings
+      @encoder.text_token("\\n\n", :error) # Visually appealing error indicator--otherwise users may wonder whether the highlighter cannot highlight multine strings
+      @encoder.end_group(:string)
+      @state = :initial
+    else
+      @encoder.text_token(getch, :error)
+    end
+  end
+
+end

From 2a2ac128a1acd37e75450073f726bf9f7e176ab3 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sat, 21 Apr 2012 23:13:46 +0200
Subject: [PATCH 02/14] Correctly highlight obscure numbers such as 0x.a3p-5.

---
 lib/coderay/scanners/lua.rb | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index 2540a2fa..49abbb17 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -48,8 +48,6 @@ def handle_state_initial
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @state = :long_string
-    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\{\}\[\]:;,] | \.(?!\d)/x)
-      @encoder.text_token(match, :operator)
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # Normal letters (or letters followed by digits)
       kind = IDENT_KIND[match]
 
@@ -62,11 +60,13 @@ def handle_state_initial
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @start_delim = match
-      @state = :string                            # hex number ←|→ decimal number
-    elsif match = scan(/0x(?:[0-9a-z])* \. [0-9a-z]+ (?:p-\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
-      @encoder.text_token(match, :float) # hex | decimal
-    elsif match = scan(/0x[0-9a-z]+ (?:p-\d+)? | \d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
+      @state = :string                 # hex number ←|→ decimal number
+    elsif match = scan(/0x\h* \. \h+ (?:p[+\-]?\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
+      @encoder.text_token(match, :float) #hex | decimal
+    elsif match = scan(/0x\h+ (?:p[+\-]?\d+)? | \d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
       @encoder.text_token(match, :integer)
+    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\{\}\[\]:;,] | \.(?!\d)/x)
+      @encoder.text_token(match, :operator)
     elsif match = scan(/\s+/)
       @encoder.text_token(match, :space)
     else

From dcf7b1d0909e323675e90c7e701fb63e41ca042a Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sat, 21 Apr 2012 23:39:35 +0200
Subject: [PATCH 03/14] =?UTF-8?q?Recognize=20=5FUPPERCASE=20tokens=20as=20?=
 =?UTF-8?q?Lua=20reserved=20idents.=20:reserved=20would=20be=20a=20more=20?=
 =?UTF-8?q?fitting=20token=20kind=20than=20:predefined,=20but=20unfortunat?=
 =?UTF-8?q?ely=20:reserved=20looks=20like=20:keyword=20in=20Coderay?=
 =?UTF-8?q?=E2=80=99s=20default=20stylesheet=20and=20this=20is=20NOT=20the?=
 =?UTF-8?q?=20same=20in=20Lua.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 lib/coderay/scanners/lua.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index 49abbb17..b05798fb 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -48,6 +48,8 @@ def handle_state_initial
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @state = :long_string
+    elsif match = scan(/_[A-Z]+/) # _UPPERCASE are names reserved for Lua
+      @encoder.text_token(match, :predefined)
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # Normal letters (or letters followed by digits)
       kind = IDENT_KIND[match]
 

From 955db8fdfb9f5c4b63cdd3cffad7b46cccbf89dc Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 12:05:49 +0200
Subject: [PATCH 04/14] Highlight goto labels

---
 lib/coderay/scanners/lua.rb | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index b05798fb..f6ea811e 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -48,13 +48,18 @@ def handle_state_initial
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @state = :long_string
+    elsif match = scan(/::\s*[a-zA-Z_][a-zA-Z0-9_]+\s*::/) # ::goto_label::
+      @encoder.text_token(match, :label)
     elsif match = scan(/_[A-Z]+/) # _UPPERCASE are names reserved for Lua
       @encoder.text_token(match, :predefined)
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # Normal letters (or letters followed by digits)
       kind = IDENT_KIND[match]
 
+      # Extra highlighting for entities following certain keywords
       if kind == :keyword and match == "function"
         @state = :function_expected
+      elsif kind == :keyword and match == "goto"
+        @state = :goto_label_expected
       end
 
       @encoder.text_token(match, kind)
@@ -82,7 +87,7 @@ def handle_state_function_expected
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # function foo()
       @encoder.text_token(match, :function)
       @state = :initial
-    elsif match = scan(/\s+/) # Between the function keyword and the ident may be any amount of whitespace
+    elsif match = scan(/\s+/) # Between the `function' keyword and the ident may be any amount of whitespace
       @encoder.text_token(match, :space)
     else
       @encoder.text_token(getch, :error)
@@ -90,6 +95,17 @@ def handle_state_function_expected
     end
   end
 
+  def handle_state_goto_label_expected
+    if match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/)
+      @encoder.text_token(match, :label)
+      @state = :initial
+    elsif match = scan(/\s+/) # Between the `goto' keyword and the label may be any amount of whitespace
+      @encoder.text_token(match, :space)
+    else
+      @encoder.text_token(getch, :error)
+    end
+  end
+
   def handle_state_long_comment
     if match = scan(/.*?(?=\]={#@num_equals}\])/m)
       @encoder.text_token(match, :content)

From 5d3ad0b97ff5d7476bfccc8747dd3f9e7df20d01 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 12:44:41 +0200
Subject: [PATCH 05/14] Highlight local variable declarations

---
 lib/coderay/scanners/lua.rb | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index f6ea811e..52e53b2c 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -60,6 +60,8 @@ def handle_state_initial
         @state = :function_expected
       elsif kind == :keyword and match == "goto"
         @state = :goto_label_expected
+      elsif kind == :keyword and match == "local"
+        @state = :local_var_expected
       end
 
       @encoder.text_token(match, kind)
@@ -106,6 +108,27 @@ def handle_state_goto_label_expected
     end
   end
 
+  def handle_state_local_var_expected
+    if match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/)
+      @encoder.text_token(match, :local_variable)
+    elsif match = scan(/,/)
+      @encoder.text_token(match, :operator)
+    elsif match = scan(/\=/)
+      @encoder.text_token(match, :operator)
+      # After encountering the equal sign, arbitrary expressions are
+      # allowed again, so just return to the main state for further
+      # parsing.
+      @state = :initial
+    elsif match = scan(/\n/)
+      @encoder.text_token(match, :space)
+      @state = :initial
+    elsif match = scan(/\s+/)
+      @encoder.text_token(match, :space)
+    else
+      @encoder.text_token(getch, :error)
+    end
+  end
+
   def handle_state_long_comment
     if match = scan(/.*?(?=\]={#@num_equals}\])/m)
       @encoder.text_token(match, :content)

From 6e2c99766ac3223012a5cedf595a9d062d11d5fc Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 15:37:44 +0200
Subject: [PATCH 06/14] Recognize the various kinds of table definitions Lua
 allows.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

tbl2 = {
  [30] = 10,
  a = 1,
  [{["a"] = "f"}] = 4,
  c = {a = 5},
  d = {a = 3, b = "fff", {["foo"] = 1}},
  e = 9,
  "foo",
  {},
  true,
  3
}

Nice, ain’t it?
---
 lib/coderay/scanners/lua.rb | 66 ++++++++++++++++++++++++++++++++++---
 1 file changed, 61 insertions(+), 5 deletions(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index 52e53b2c..b1eeaef3 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -22,7 +22,8 @@ class CodeRay::Scanners::Lua < CodeRay::Scanners::Scanner
   protected
 
   def setup
-    @state = :initial
+    @state       = :initial
+    @brace_depth = 0
   end
 
   def scan_tokens(encoder, options)
@@ -41,17 +42,22 @@ def handle_state_initial
       @encoder.begin_group(:comment)
       @encoder.text_token(match, :delimiter)
       @state = :long_comment
+
     elsif match = scan(/--.*?$/) # --Lua comment
       @encoder.text_token(match, :comment)
+
     elsif match = scan(/\[=*\[/)     # [[ long (possibly multiline) string ]]
       @num_equals = match.count("=") # Number must match for comment end
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @state = :long_string
+
     elsif match = scan(/::\s*[a-zA-Z_][a-zA-Z0-9_]+\s*::/) # ::goto_label::
       @encoder.text_token(match, :label)
+
     elsif match = scan(/_[A-Z]+/) # _UPPERCASE are names reserved for Lua
       @encoder.text_token(match, :predefined)
+
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # Normal letters (or letters followed by digits)
       kind = IDENT_KIND[match]
 
@@ -65,22 +71,54 @@ def handle_state_initial
       end
 
       @encoder.text_token(match, kind)
+
+    elsif match = scan(/{/)
+      @encoder.begin_group(:table)
+      @encoder.text_token(match, @brace_depth >= 1 ? :inline_delimiter : :delimiter)
+      @brace_depth += 1
+      @state        = :table
+
+    elsif match = scan(/}/)
+      if @brace_depth == 1
+        @brace_depth = 0
+        @encoder.text_token(match, :delimiter)
+      elsif @brace_depth == 0 # Mismatched brace
+        @encoder.text_token(match, :error)
+      else
+        @brace_depth -= 1
+        @encoder.text_token(match, :inline_delimiter)
+        @state = :table
+      end
+      @encoder.end_group(:table)
+
     elsif match = scan(/["']/)
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @start_delim = match
-      @state = :string                 # hex number ←|→ decimal number
+      @state = :string
+
+                                       # hex number ←|→ decimal number
     elsif match = scan(/0x\h* \. \h+ (?:p[+\-]?\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
-      @encoder.text_token(match, :float) #hex | decimal
+      @encoder.text_token(match, :float)
+
+                                # hex number ←|→ decimal number
     elsif match = scan(/0x\h+ (?:p[+\-]?\d+)? | \d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
       @encoder.text_token(match, :integer)
-    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\{\}\[\]:;,] | \.(?!\d)/x)
+
+    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\[\]:;,] | \.(?!\d)/x)
       @encoder.text_token(match, :operator)
+
     elsif match = scan(/\s+/)
       @encoder.text_token(match, :space)
+
     else
       @encoder.text_token(getch, :error)
     end
+
+    # It may be that we’re scanning a full-blown subexpression of a table
+    # (tables can contain full expressions in parts).
+    # If this is the case, return to :table scanning state.
+    @state = :table if @state == :initial && @brace_depth >= 1
   end
 
   def handle_state_function_expected
@@ -113,7 +151,7 @@ def handle_state_local_var_expected
       @encoder.text_token(match, :local_variable)
     elsif match = scan(/,/)
       @encoder.text_token(match, :operator)
-    elsif match = scan(/\=/)
+    elsif match = scan(/=/)
       @encoder.text_token(match, :operator)
       # After encountering the equal sign, arbitrary expressions are
       # allowed again, so just return to the main state for further
@@ -175,4 +213,22 @@ def handle_state_string
     end
   end
 
+  def handle_state_table
+    if match = scan(/[,;]/)
+      @encoder.text_token(match, :operator)
+    elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]* (?=\s*=)/x)
+      @encoder.text_token(match, :key)
+      @encoder.text_token(scan(/\s+/), :space) if check(/\s+/)
+      @encoder.text_token(scan(/=/), :operator)
+      @state = :initial
+    elsif match = scan(/\s+/m)
+      @encoder.text_token(match, :space)
+    else
+      # Note this clause doesn’t advance the scan pointer, it’s a kind of
+      # "retry with other options" (the :initial state then of course
+      # advances the pointer).
+      @state = :initial
+    end
+  end
+
 end

From e9f5c285306fcdee29f89875286b914ccec33bbc Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 18:22:11 +0200
Subject: [PATCH 07/14] Allow local functions

---
 lib/coderay/scanners/lua.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index b1eeaef3..3ba06130 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -147,7 +147,10 @@ def handle_state_goto_label_expected
   end
 
   def handle_state_local_var_expected
-    if match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/)
+    if match = scan(/function/) # local function ...
+      @encoder.text_token(match, :keyword)
+      @state = :function_expected
+    elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/)
       @encoder.text_token(match, :local_variable)
     elsif match = scan(/,/)
       @encoder.text_token(match, :operator)

From 535ff2fb70f1a9f8849afafc139058ef119d4b60 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 18:31:59 +0200
Subject: [PATCH 08/14] Allow more obscure function definitions with colon as
 the last separator. tbl = {} function tbl:foo(self)   print("foo") end

---
 lib/coderay/scanners/lua.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index 3ba06130..f5a8c494 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -122,7 +122,7 @@ def handle_state_initial
   end
 
   def handle_state_function_expected
-    if match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* \./x) # function tbl.subtbl.foo()
+    if match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* [\.\:]/x) # function tbl.subtbl.foo() | function tbl:foo() # Colon only allowed as last separator
       @encoder.text_token(match, :ident)
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # function foo()
       @encoder.text_token(match, :function)

From 8c9f53fe40c10cafc629d3b332c74d01fdb0a049 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 18:44:18 +0200
Subject: [PATCH 09/14] Allow anonymous function definitions. x = function()
 print("anon") end

---
 lib/coderay/scanners/lua.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index f5a8c494..9915c14d 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -122,7 +122,10 @@ def handle_state_initial
   end
 
   def handle_state_function_expected
-    if match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* [\.\:]/x) # function tbl.subtbl.foo() | function tbl:foo() # Colon only allowed as last separator
+    if match = scan(/\(\s*\)/) # x = function() # "Anonymous" function without explicit name
+      @encoder.text_token(match, :operator)
+      @state = :initial
+    elsif match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* [\.\:]/x) # function tbl.subtbl.foo() | function tbl:foo() # Colon only allowed as last separator
       @encoder.text_token(match, :ident)
     elsif match = scan(/[a-zA-Z_][a-zA-Z0-9_]*/) # function foo()
       @encoder.text_token(match, :function)

From dc0e15ae025dd075ac4ea061406a0546a580f2bb Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 19:21:25 +0200
Subject: [PATCH 10/14] Recognize predefined expressions, i.e. functions and
 other idents provided by the `base' library. print, error, garbagecollect,
 ...

---
 lib/coderay/scanners/lua.rb | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index 9915c14d..ad1ffb03 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -1,38 +1,65 @@
 # -*- coding: utf-8 -*-
 
-# http://www.lua.org/manual/5.2/manual.html
+# Scanner for the Lua[http://lua.org] programming lanuage.
+#
+# The language’s complete syntax is defined in
+# {the Lua manual}[http://www.lua.org/manual/5.2/manual.html],
+# which is what this scanner tries to conform to.
 class CodeRay::Scanners::Lua < CodeRay::Scanners::Scanner
 
   register_for :lua
   file_extension "lua"
   title "Lua"
 
+  # Keywords used in Lua.
   KEYWORDS = %w[and break do else elseif end
   for function goto if in
   local not or repeat return
   then until while
   ]
 
+  # Constants set by the Lua core.
   PREDEFINED_CONSTANTS = %w[false true nil]
 
+  # The expressions contained in this array are parts of Lua’s `basic'
+  # library. Although it’s not entirely necessary to load that library,
+  # it is highly recommended and one would have to provide own implementations
+  # of some of these expressions if one does not do so. They however aren’t
+  # keywords, neither are they constants, but nearly predefined, so they
+  # get tagged as `predefined' rather than anything else.
+  #
+  # This list excludes values of form `_UPPERCASE' because the Lua manual
+  # requires such identifiers to be reserved by Lua anyway and they are
+  # highlighted directly accordingly, without the need for specific
+  # identifiers to be listed here.
+  PREDEFINED_EXPRESSIONS = %w[
+  assert collectgarbage dofile error getmetatable
+  ipairs load loadfile next pairs pcall print
+  rawequal rawget rawlen rawset select setmetatable
+  tonumber tostring type xpcall
+  ]
+
+  # Automatic token kind selection for normal words.
   IDENT_KIND = CodeRay::WordList.new(:ident)
     .add(KEYWORDS, :keyword)
     .add(PREDEFINED_CONSTANTS, :predefined_constant)
+    .add(PREDEFINED_EXPRESSIONS, :predefined)
 
   protected
 
+  # Scanner initialization.
   def setup
     @state       = :initial
     @brace_depth = 0
   end
 
+  # CodeRay entry hook. Starts parsing.
   def scan_tokens(encoder, options)
     @encoder = encoder
     @options = options
 
     send(:"handle_state_#@state") until eos?
 
-
     @encoder
   end
 

From 5b3efc31412371c32e0f7fc22fca2131c90ec933 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 19:40:40 +0200
Subject: [PATCH 11/14] Anonymous functions with parameters

---
 lib/coderay/scanners/lua.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index ad1ffb03..eb8100c6 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -149,7 +149,7 @@ def handle_state_initial
   end
 
   def handle_state_function_expected
-    if match = scan(/\(\s*\)/) # x = function() # "Anonymous" function without explicit name
+    if match = scan(/\(.*?\)/m) # x = function() # "Anonymous" function without explicit name
       @encoder.text_token(match, :operator)
       @state = :initial
     elsif match = scan(/[a-zA-Z_] (?:[a-zA-Z0-9_\.] (?!\.\d))* [\.\:]/x) # function tbl.subtbl.foo() | function tbl:foo() # Colon only allowed as last separator

From 800431a00c0fe129b163859ab5c62d651d4cc3ad Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 20:17:46 +0200
Subject: [PATCH 12/14] Add CSS styles for table highlighting.

---
 lib/coderay/styles/alpha.rb | 3 +++
 lib/coderay/token_kinds.rb  | 1 +
 2 files changed, 4 insertions(+)

diff --git a/lib/coderay/styles/alpha.rb b/lib/coderay/styles/alpha.rb
index 8506d103..257083e5 100644
--- a/lib/coderay/styles/alpha.rb
+++ b/lib/coderay/styles/alpha.rb
@@ -116,6 +116,9 @@ class Alpha < Style
 .symbol .content { color:#A60 }
 .symbol .delimiter { color:#630 }
 .symbol { color:#A60 }
+.table .content { color:#808 }
+.table .delimiter { color:#40A}
+.table { background-color:hsla(200,100%,50%,0.06); }
 .tag { color:#070 }
 .type { color:#339; font-weight:bold }
 .value { color: #088; }
diff --git a/lib/coderay/token_kinds.rb b/lib/coderay/token_kinds.rb
index 3b8d07e4..e2456235 100755
--- a/lib/coderay/token_kinds.rb
+++ b/lib/coderay/token_kinds.rb
@@ -63,6 +63,7 @@ module CodeRay
     :shell               => 'shell',
     :string              => 'string',
     :symbol              => 'symbol',
+    :table               => 'table',
     :tag                 => 'tag',
     :type                => 'type',
     :value               => 'value',

From 9dc21e57ea0fbd1e7869405d206dc906aef1aee6 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 20:32:52 +0200
Subject: [PATCH 13/14] Take unary - as part of the number rather than an
 operator. Note Lua has no unary +.

---
 lib/coderay/scanners/lua.rb | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index eb8100c6..b7e745df 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -124,12 +124,12 @@ def handle_state_initial
       @start_delim = match
       @state = :string
 
-                                       # hex number ←|→ decimal number
-    elsif match = scan(/0x\h* \. \h+ (?:p[+\-]?\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
+                      # ↓Prefix                hex number ←|→ decimal number
+    elsif match = scan(/-? (?:0x\h* \. \h+ (?:p[+\-]?\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?)/ix) # hexadecimal constants have no E power, decimal ones no P power
       @encoder.text_token(match, :float)
 
-                                # hex number ←|→ decimal number
-    elsif match = scan(/0x\h+ (?:p[+\-]?\d+)? | \d+ (?:e[+\-]?\d+)?/ix) # hexadecimal constants have no E power, decimal ones no P power
+                      # ↓Prefix         hex number ←|→ decimal number
+    elsif match = scan(/-? (?:0x\h+ (?:p[+\-]?\d+)? | \d+ (?:e[+\-]?\d+)?)/ix) # hexadecimal constants have no E power, decimal ones no P power
       @encoder.text_token(match, :integer)
 
     elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\[\]:;,] | \.(?!\d)/x)

From e339a68fbe1084fc22b735623c9bde42d9383d42 Mon Sep 17 00:00:00 2001
From: Quintus <sutniuq@gmx.net>
Date: Sun, 22 Apr 2012 20:47:51 +0200
Subject: [PATCH 14/14] Add some informative comments

---
 lib/coderay/scanners/lua.rb | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
index b7e745df..e7706fc1 100644
--- a/lib/coderay/scanners/lua.rb
+++ b/lib/coderay/scanners/lua.rb
@@ -99,13 +99,13 @@ def handle_state_initial
 
       @encoder.text_token(match, kind)
 
-    elsif match = scan(/{/)
+    elsif match = scan(/{/) # Opening table brace {
       @encoder.begin_group(:table)
       @encoder.text_token(match, @brace_depth >= 1 ? :inline_delimiter : :delimiter)
       @brace_depth += 1
       @state        = :table
 
-    elsif match = scan(/}/)
+    elsif match = scan(/}/) # Closing table brace }
       if @brace_depth == 1
         @brace_depth = 0
         @encoder.text_token(match, :delimiter)
@@ -118,11 +118,11 @@ def handle_state_initial
       end
       @encoder.end_group(:table)
 
-    elsif match = scan(/["']/)
+    elsif match = scan(/["']/) # String delimiters " and '
       @encoder.begin_group(:string)
       @encoder.text_token(match, :delimiter)
       @start_delim = match
-      @state = :string
+      @state       = :string
 
                       # ↓Prefix                hex number ←|→ decimal number
     elsif match = scan(/-? (?:0x\h* \. \h+ (?:p[+\-]?\d+)? | \d*\.\d+ (?:e[+\-]?\d+)?)/ix) # hexadecimal constants have no E power, decimal ones no P power
@@ -132,13 +132,13 @@ def handle_state_initial
     elsif match = scan(/-? (?:0x\h+ (?:p[+\-]?\d+)? | \d+ (?:e[+\-]?\d+)?)/ix) # hexadecimal constants have no E power, decimal ones no P power
       @encoder.text_token(match, :integer)
 
-    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\[\]:;,] | \.(?!\d)/x)
+    elsif match = scan(/[\+\-\*\/%^\#=~<>\(\)\[\]:;,] | \.(?!\d)/x) # Operators
       @encoder.text_token(match, :operator)
 
-    elsif match = scan(/\s+/)
+    elsif match = scan(/\s+/) # Space
       @encoder.text_token(match, :space)
 
-    else
+    else # Invalid stuff. Note that Lua doesn’t accept multibyte chars outside of strings, hence these are also errors.
       @encoder.text_token(getch, :error)
     end