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

Instance Method Summary collapse

Constructor Details

#initialize(language) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/decode/language/ruby/parser.rb', line 26

def initialize(language)
	@language = language
	
	@visibility = :public
	@definitions = Hash.new.compare_by_identity
end

Instance Method Details

#constant_names_for(children) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 301

def constant_names_for(children)
	children.each do |node|
		if node.type == :sym
			yield node.children[0]
		end
	end
end

#definitions_for(source, &block) ⇒ Object

Extract definitions from the given input file.



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# File 'lib/decode/language/ruby/parser.rb', line 52

def definitions_for(source, &block)
	top, comments = self.parse_source(source)
	
	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 60

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 273

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 234

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

#nested_name_for(node) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 251

def nested_name_for(node)
	if prefix = node.children[0]
		"#{nested_name_for(prefix)}::#{node.children[1]}".to_sym
	else
		node.children[1]
	end
end

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



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# File 'lib/decode/language/ruby/parser.rb', line 287

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: @language)
				yield scope
				scope
			end
		end
	end
	
	return parent
end

#segments_for(source, &block) ⇒ Object

Extract segments from the given input file.



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# File 'lib/decode/language/ruby/parser.rb', line 310

def segments_for(source, &block)
	top, comments = self.parse_source(source)
	
	# 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

#singleton_name_for(node) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 259

def singleton_name_for(node)
	case node.type
	when :const
		nested_name_for(node)
	when :self
		:'self'
	end
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 94

def walk_definitions(node, comments, parent = nil, &block)
	case node.type
	when :module
		definition = Module.new(
			node, nested_name_for(node.children[0]),
			comments: extract_comments_for(node, comments),
			parent: parent,
			language: @language, visibility: :public
		)
		
		assign_definition(parent, definition)
		
		yield definition
		
		if children = node.children[1]
			with_visibility do
				walk_definitions(children, comments, definition, &block)
			end
		end
	when :class
		definition = Class.new(
			node, nested_name_for(node.children[0]),
			comments: extract_comments_for(node, comments),
			parent: parent, language: @language, visibility: :public
		)
		
		assign_definition(parent, definition)
		
		yield definition
		
		if children = node.children[2]
			with_visibility do
				walk_definitions(children, comments, definition, &block)
			end
		end
	when :sclass
		if name = singleton_name_for(node.children[0])
			definition = Singleton.new(
				node, name,
				comments: extract_comments_for(node, comments),
				parent: parent, language: @language, visibility: :public
			)
			
			yield definition
			
			if children = node.children[1]
				walk_definitions(children, comments, definition, &block)
			end
		end
	when :def
		definition = Method.new(
			node, node.children[0],
			comments: extract_comments_for(node, comments),
			parent: parent, language: @language, visibility: @visibility
		)
		
		yield definition
	when :defs
		extracted_comments = extract_comments_for(node, comments)
		
		definition = Function.new(
			node, node.children[1],
			comments: extracted_comments,
			parent: scope_for(extracted_comments, parent, &block),
			language: @language, visibility: @visibility
		)
		
		yield definition
	when :casgn
		definition = Constant.new(
			node, node.children[1],
			comments: extract_comments_for(node, comments),
			parent: parent, language: @language
		)
		
		yield definition
	when :send
		name = node.children[1]
		
		case name
		when :public, :protected, :private
			@visibility = name
		when :private_constant
			constant_names_for(node.children[2..]) do |name|
				if definition = lookup_definition(parent, name)
					definition.visibility = :private
				end
			end
		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: @language
			)
			
			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: @language
				)
				
				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: @language
			)
			
			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
	else
		node.children.each do |child|
			if child.is_a?(::Parser::AST::Node)
				walk_definitions(child, comments, parent, &block) if child
			end
		end
	end
end

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



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# File 'lib/decode/language/ruby/parser.rb', line 329

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),
					@language,	child
				)
			elsif next_comments = extract_comments_for(child, comments)
				yield segment if segment
				segment = Segment.new(next_comments, @language, child)
			else
				segment.expand(child)
			end
		end
		
		yield segment if segment
	else
		# One top level segment:
		segment = Segment.new(
			extract_comments_for(node, comments),
			@language, node
		)
		
		yield segment
	end
end

#with_visibility(visibility = :public, &block) ⇒ Object 



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# File 'lib/decode/language/ruby/parser.rb', line 85

def with_visibility(visibility = :public, &block)
	saved_visibility = @visibility
	@visibility = visibility
	yield
ensure
	@visibility = saved_visibility
end