# Class: YARD::Handlers::Ruby::Legacy::ClassConditionHandler

Inherits:
  Base
  - Object
  - Base
  - Base
  - YARD::Handlers::Ruby::Legacy::ClassConditionHandler
  show all

Defined in:
  lib/yard/handlers/ruby/legacy/class_condition_handler.rb

## Overview

Matches if/unless conditions inside classes and attempts to process only one branch (by evaluating the condition if possible).

#### Examples:

#####

A simple class conditional

    class Foo
      if 0
        # This method is ignored
        def xyz; end
      end
    end

Since:

- 0.5.4

## Constant Summary

### Constants included from Parser::Ruby::Legacy::RubyToken

Parser::Ruby::Legacy::RubyToken::EXPR_ARG, Parser::Ruby::Legacy::RubyToken::EXPR_BEG, Parser::Ruby::Legacy::RubyToken::EXPR_CLASS, Parser::Ruby::Legacy::RubyToken::EXPR_DOT, Parser::Ruby::Legacy::RubyToken::EXPR_END, Parser::Ruby::Legacy::RubyToken::EXPR_FNAME, Parser::Ruby::Legacy::RubyToken::EXPR_MID, Parser::Ruby::Legacy::RubyToken::NEWLINE_TOKEN, Parser::Ruby::Legacy::RubyToken::TkReading2Token, Parser::Ruby::Legacy::RubyToken::TkSymbol2Token

### Constants included from CodeObjects

CodeObjects::BUILTIN_ALL, CodeObjects::BUILTIN_CLASSES, CodeObjects::BUILTIN_EXCEPTIONS, CodeObjects::BUILTIN_EXCEPTIONS_HASH, CodeObjects::BUILTIN_MODULES, CodeObjects::CONSTANTMATCH, CodeObjects::CONSTANTSTART, CodeObjects::CSEP, CodeObjects::CSEPQ, CodeObjects::ISEP, CodeObjects::ISEPQ, CodeObjects::METHODMATCH, CodeObjects::METHODNAMEMATCH, CodeObjects::NAMESPACEMATCH, CodeObjects::NSEP, CodeObjects::NSEPQ

## Instance Method Summary collapse

- #parse_condition ⇒ true, ... protected

  Parses the condition part of the if/unless statement.

- #parse_else_block ⇒ Object protected
- #parse_then_block ⇒ Object protected
- #process ⇒ void

  Main processing callback.

### Methods included from CodeObjects::NamespaceMapper

#clear_separators, #default_separator, on_invalidate, #register_separator, #separators, #separators_for_type, #separators_match, #types_for_separator, #unregister_separator_by_type

## Constructor Details

This class inherits a constructor from YARD::Handlers::Base

## Instance Method Details

### #parse_condition ⇒ `true`, ... (protected)

Parses the condition part of the if/unless statement

Returns:

- (`true`, `false`, `nil`) —

  true if the condition can be definitely parsed to true, false if not, and nil if the condition cannot be parsed with certainty (it’s dynamic)

Since:

- 0.5.5

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    # File 'lib/yard/handlers/ruby/legacy/class_condition_handler.rb', line 29

    def parse_condition
      condition = nil

      # Right now we can handle very simple unary conditions like:
      #   if true
      #   if false
      #   if 0
      #   if 100 (not 0)
      #   if defined? SOME_CONSTANT
      #
      # The last case will do a lookup in the registry and then one
      # in the Ruby world (using eval).
      case statement.tokens[1..-1].to_s.strip
      when /^(\d+)$/
        condition = $1 != "0"
      when /^defined\?\s*\(?\s*([A-Za-z0-9:_]+?)\s*\)?$/
        # defined? keyword used, let's see if we can look up the name
        # in the registry, then we'll try using Ruby's powers. eval() is not
        # *too* dangerous here since code is not actually executed.
        name = $1
        obj = YARD::Registry.resolve(namespace, name, true)
        begin
          condition = true if obj || Object.instance_eval("defined? #{name}")
        rescue SyntaxError, NameError
          condition = false
        end
      when "true"
        condition = true
      when "false"
        condition = false
      end

      if TkUNLESS === statement.tokens.first
        condition = !condition unless condition.nil?
      end
      condition
    end

### #parse_else_block ⇒ `Object` (protected)

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- 0.5.5

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    # File 'lib/yard/handlers/ruby/legacy/class_condition_handler.rb', line 73

    def parse_else_block
      return unless statement.block
      stmtlist = YARD::Parser::Ruby::Legacy::StatementList
      stmtlist.new(statement.block).each do |stmt|
        next unless TkELSE === stmt.tokens.first
        push_state(:visibility => visibility) do
          parser.process(stmtlist.new(stmt.block))
        end
      end
    end

### #parse_then_block ⇒ `Object` (protected)

Since:

- 0.5.5

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    # File 'lib/yard/handlers/ruby/legacy/class_condition_handler.rb', line 68

    def parse_then_block
      parse_block(:visibility => visibility)
    end

### #process ⇒ `void`

This method returns an undefined value.

Main processing callback

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    # File 'lib/yard/handlers/ruby/legacy/class_condition_handler.rb', line 8

    process do
      condition = parse_condition
      if condition.nil?
        # Parse both blocks if we're unsure of the condition
        parse_then_block
        parse_else_block
      elsif condition
        parse_then_block
      else
        parse_else_block
      end
    end