Quick-n-dirty Lua scanner

Phrogz · Phrogz · commit a92f44c57a67 · 2013-05-31T23:31:18.000-04:00
diff --git a/lib/coderay/scanners/lua.rb b/lib/coderay/scanners/lua.rb
@@ -0,0 +1,111 @@
+# -*- coding: utf-8 -*-
+
+# 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 = %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]
+
+  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
+  ]
+
+  SCANNER = /
+    (?<fluff>[\d\D]*?) # eat content up until something we want
+    (?:
+      \b(?<keyword>#{KEYWORDS.join('|')})\b
+      |
+      (?<blockcomment>
+        --\[(?<commentequals>=*)\[[\d\D]*?\]\k<commentequals>\]
+      )
+      |
+      (?:
+        (?<s1q1>")(?<s1>(?:[^\\"\n]|\\[abfnrtvz\\"']|\\\n|\\\d{1,3}|\\x[\da-fA-F]{2})*)(?<s1q2>")
+        |
+        (?<s2q1>')(?<s2>(?:[^\\'\n]|\\[abfnrtvz\\"']|\\\n|\\\d{1,3}|\\x[\da-fA-F]{2})*)(?<s2q2>')
+        |
+        (?<s3q1>\[(?<stringequals>=*)\[)(?<s3>[\d\D]*?)(?<s3q2>\]\k<stringequals>\])
+      )
+      |
+      (?<comment>
+        --(?!\[).+
+      )
+      |
+      (?<number>
+        -? # Allows -2 to be properly highlighted, but makes 10-5 show -5 as a single number
+        (?:
+          0[xX][\da-fA-F]+
+          |
+          (?:
+            \d+\.?\d*
+            |
+            \d*\.?\d+
+          )
+          (?:[eE][-+]?\d+)?
+        )
+      )
+      |
+      \b(?<constant>#{PREDEFINED_CONSTANTS.join('|')})\b
+      |
+      \b(?<library>#{PREDEFINED_EXPRESSIONS.join('|')})\b
+      |
+      (?<gotolabel>
+        ::[a-zA-Z_]\w*::
+      )
+      |
+      (?<reserved>
+        \b_[A-Z]+\b
+      )
+    )
+  /x
+
+  CAPTURE_KINDS = {
+    fluff:        :content,
+    reserved:     :reserved,
+    comment:      :comment,
+    blockcomment: :comment,
+    keyword:      :keyword,
+    number:       :float,
+    constant:     :"predefined-constant",
+    library:      :predefined,
+    s1q1:         :delimiter,
+    s1:           :string,
+    s1q2:         :delimiter,
+    s2q1:         :delimiter,
+    s2:           :string,
+    s2q2:         :delimiter,
+    s3q1:         :delimiter,
+    s3:           :string,
+    s3q2:         :delimiter,
+    gotolabel:    :label,
+  }
+
+  protected
+
+  def scan_tokens(tokens, options)
+    string.gsub(SCANNER) do
+      CAPTURE_KINDS.each do |capture,kind|
+        tokens.text_token( $~[capture], kind ) if $~[capture] && !$~[capture].empty?
+      end
+    end
+    tokens
+  end
+
+end
