Class: Decode::Language::Ruby::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/decode/language/ruby/parser.rb

Overview

The Ruby source code parser.

Constant Summary collapse

NAME_ATTRIBUTE = 
/\A@name\s+(?<value>.*?)\Z/
KIND_ATTRIBUTE = 
/\A
  (@(?<kind>attr)\s+(?<value>.*?))|
  (@define\s+(?<kind>)\s+(?<value>.*?))
\Z/x
SCOPE_ATTRIBUTE = 
/\A
  (@scope\s+(?<names>.*?))
\Z/x

Instance Method Summary collapse

Instance Method Details

#definitions_for(input, &block) ⇒ Object

Extract definitions from the given input file.



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# File 'lib/decode/language/ruby/parser.rb', line 42

def definitions_for(input, &block)
  top, comments = ::Parser::CurrentRuby.parse_with_comments(input.read)
  
  if top
    walk_definitions(top, comments, &block)
  end
end

#extract_comments_for(node, comments) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 50

def extract_comments_for(node, comments)
  prefix = []
  
  while comment = comments.first
    break if comment.location.line >= node.location.line
    
    if last_comment = prefix.last
      if last_comment.location.line != (comment.location.line - 1)
        prefix.clear
      end
    end
    
    prefix << comments.shift
  end
  
  # The last comment must butt up against the node:
  if comment = prefix.last
    if comment.location.line == (node.location.line - 1)
      return prefix.map do |comment|
        comment.text.sub(/\A\#\s?/, '')
      end
    end
  end
end

#kind_for(node, comments = nil) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 214

def kind_for(node, comments = nil)
  comments&.each do |comment|
    if match = comment.match(KIND_ATTRIBUTE)
      return match[:kind].to_sym
    end
  end
  
  return nil
end

#name_for(node, comments = nil) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 192

def name_for(node, comments = nil)
  comments&.each do |comment|
    if match = comment.match(NAME_ATTRIBUTE)
      return match[:value].to_sym
    end
  end
  
  case node.type
  when :sym
    return node.children[0]
  when :send
    return node.children[1]
  when :block
    return node.children[0].children[1]
  end
end

#scope_for(comments, parent = nil, &block) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 228

def scope_for(comments, parent = nil, &block)
  comments&.each do |comment|
    if match = comment.match(SCOPE_ATTRIBUTE)
      return match[:names].split(/\s+/).map(&:to_sym).inject(nil) do |memo, name|
        scope = Scope.new(name, parent: memo, language: Ruby)
        yield scope
        scope
      end
    end
  end
  
  return parent
end

#segments_for(input, &block) ⇒ Object

Extract segments from the given input file.



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# File 'lib/decode/language/ruby/parser.rb', line 243

def segments_for(input, &block)
  top, comments = ::Parser::CurrentRuby.parse_with_comments(input.read)
  
  # We delete any leading comments:
  line = 0
  
  while comment = comments.first
    if comment.location.line == line
      comments.pop
      line += 1
    else
      break
    end
  end
  
  # Now we iterate over the syntax tree and generate segments:
  walk_segments(top, comments, &block)
end

#walk_definitions(node, comments, parent = nil, &block) ⇒ Object

Walk over the syntax tree and extract relevant definitions with their associated comments.



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# File 'lib/decode/language/ruby/parser.rb', line 76

def walk_definitions(node, comments, parent = nil, &block)
  case node.type
  when :begin
    node.children.each do |child|
      walk_definitions(child, comments, parent, &block)
    end
  when :module
    definition = Module.new(
      node, node.children[0].children[1],
      comments: extract_comments_for(node, comments),
      parent: parent,
      language: Ruby
    )
    
    yield definition
    
    if children = node.children[1]
      walk_definitions(children, comments, definition, &block)
    end
  when :class
    definition = Class.new(
      node, node.children[0].children[1],
      comments: extract_comments_for(node, comments),
      parent: parent, language: Ruby
    )
    
    yield definition
    
    if children = node.children[2]
      walk_definitions(children, comments, definition, &block)
    end
  when :sclass
    definition = Singleton.new(
      node, node.children[0],
      comments: extract_comments_for(node, comments),
      parent: parent, language: Ruby
    )
    
    yield definition
    
    if children = node.children[1]
      walk_definitions(children, comments, definition, &block)
    end
  when :def
    definition = Method.new(
      node, node.children[0],
      comments: extract_comments_for(node, comments),
      parent: parent, language: Ruby
    )
    
    yield definition
  when :defs
    definition = Function.new(
      node, node.children[1],
      comments: extract_comments_for(node, comments),
      parent: parent, language: Ruby
    )
    
    yield definition
  when :casgn
    definition = Constant.new(
      node, node.children[1],
      comments: extract_comments_for(node, comments),
      parent: parent, language: Ruby
    )
    
    yield definition
  when :send
    name = node.children[1]
    case name
    when :attr, :attr_reader, :attr_writer, :attr_accessor
      definition = Attribute.new(
        node, name_for(node.children[2]),
        comments: extract_comments_for(node, comments),
        parent: parent, language: Ruby
      )
      
      yield definition
    else
      extracted_comments = extract_comments_for(node, comments)
      if kind = kind_for(node, extracted_comments)
        definition = Call.new(
          node, name_for(node, extracted_comments),
          comments: extracted_comments,
          parent: parent, language: Ruby
        )
        
        yield definition
      end
    end
  when :block
    extracted_comments = extract_comments_for(node, comments)
    
    if name = name_for(node, extracted_comments)
      definition = Block.new(
        node, name,
        comments: extracted_comments,
        parent: scope_for(extracted_comments, parent, &block),
        language: Ruby
      )
      
      if kind = kind_for(node, extracted_comments)
        definition = definition.convert(kind)
      end
      
      yield definition
      
      if children = node.children[2]
        walk_definitions(children, comments, definition, &block)
      end
    end
  end
end

#walk_segments(node, comments, &block) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 262

def walk_segments(node, comments, &block)
  case node.type
  when :begin
    segment = nil
    
    node.children.each do |child|
      if segment.nil?
        segment = Segment.new(
          extract_comments_for(child, comments),
          Ruby,  child
        )
      elsif next_comments = extract_comments_for(child, comments)
        yield segment if segment
        segment = Segment.new(next_comments, Ruby, child)
      else
        segment.expand(child)
      end
    end
    
    yield segment if segment
  end
end