Rename to propane

lib/propane.rb

@@ -0,0 +1,137 @@
+require "erb"
+require "set"
+require_relative "propane/cli"
+require_relative "propane/code_point_range"
+require_relative "propane/fa"
+require_relative "propane/fa/state"
+require_relative "propane/fa/state/transition"
+require_relative "propane/lexer"
+require_relative "propane/lexer/dfa"
+require_relative "propane/parser"
+require_relative "propane/parser/item"
+require_relative "propane/parser/item_set"
+require_relative "propane/regex"
+require_relative "propane/regex/nfa"
+require_relative "propane/regex/unit"
+require_relative "propane/rule"
+require_relative "propane/token"
+require_relative "propane/version"
+
+class Propane
+
+  # EOF.
+  TOKEN_EOF = 0xFFFFFFFC
+
+  # Decoding error.
+  TOKEN_DECODE_ERROR = 0xFFFFFFFD
+
+  # Token ID for a "dropped" token.
+  TOKEN_DROP = 0xFFFFFFFE
+
+  # Invalid token ID.
+  TOKEN_NONE = 0xFFFFFFFF
+
+  class Error < RuntimeError
+  end
+
+  def initialize(input)
+    @tokens = {}
+    @rules = {}
+    input = input.gsub("\r\n", "\n")
+    while !input.empty?
+      parse_grammar(input)
+    end
+  end
+
+  def generate(output_file, log_file)
+    expand_rules
+    lexer = Lexer.new(@tokens)
+    parser = Parser.new(@tokens, @rules)
+    classname = @classname || File.basename(output_file).sub(%r{[^a-zA-Z0-9].*}, "").capitalize
+    erb = ERB.new(File.read(File.join(File.dirname(File.expand_path(__FILE__)), "../assets/parser.d.erb")), trim_mode: "<>")
+    result = erb.result(binding.clone)
+    File.open(output_file, "wb") do |fh|
+      fh.write(result)
+    end
+  end
+
+  private
+
+  def parse_grammar(input)
+    if input.slice!(/\A\s+/)
+      # Skip white space.
+    elsif input.slice!(/\A#.*\n/)
+      # Skip comment lines.
+    elsif input.slice!(/\Amodule\s+(\S+)\n/)
+      @modulename = $1
+    elsif input.slice!(/\Aclass\s+(\S+)\n/)
+      @classname = $1
+    elsif input.slice!(/\Atoken\s+(\S+)(?:\s+(\S+))?\n/)
+      name, pattern = $1, $2
+      if pattern.nil?
+        pattern = name
+      end
+      unless name =~ /^[a-zA-Z_][a-zA-Z_0-9]*$/
+        raise Error.new("Invalid token name #{name}")
+      end
+      if @tokens[name]
+        raise Error.new("Duplicate token name #{name}")
+      else
+        @tokens[name] = Token.new(name, pattern, @tokens.size)
+      end
+    elsif input.slice!(/\Adrop\s+(\S+)\n/)
+      pattern = $1
+      @tokens[name] = Token.new(nil, pattern, @tokens.size)
+    elsif input.slice!(/\A(\S+)\s*:\s*\[(.*?)\] <<\n(.*?)^>>\n/m)
+      rule_name, components, code = $1, $2, $3
+      components = components.strip.split(/\s+/)
+      @rules[rule_name] ||= Rule.new(rule_name, @rules.size)
+      @rules[rule_name].add_pattern(components, code)
+    else
+      if input.size > 25
+        input = input.slice(0..20) + "..."
+      end
+      raise Error.new("Unexpected grammar input: #{input}")
+    end
+  end
+
+  def expand_rules
+    @rules.each do |rule_name, rule|
+      if @tokens.include?(rule_name)
+        raise Error.new("Rule name collides with token name #{rule_name}")
+      end
+    end
+    unless @rules["Start"]
+      raise Error.new("Start rule not found")
+    end
+    @rules.each do |rule_name, rule|
+      rule.patterns.each do |rule|
+        rule.components.map! do |component|
+          if @tokens[component]
+            @tokens[component]
+          elsif @rules[component]
+            @rules[component]
+          else
+            raise Error.new("Symbol #{component} not found")
+          end
+        end
+      end
+    end
+  end
+
+  class << self
+
+    def run(input_file, output_file, log_file)
+      begin
+        propane = Propane.new(File.read(input_file))
+        propane.generate(output_file, log_file)
+      rescue Error => e
+        $stderr.puts e.message
+        return 2
+      end
+      return 0
+    end
+
+  end
+
+end