Module: MethodSource::CodeHelpers

Included in:
MethodSource
Defined in:
lib/method_source/code_helpers.rb

Defined Under Namespace

Modules: IncompleteExpression

Instance Method Summary collapse

Instance Method Details

#comment_describing(file, line_number) ⇒ String

Retrieve the comment describing the expression on the given line of the given file.

This is useful to get module or method documentation.


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# File 'lib/method_source/code_helpers.rb', line 52

def comment_describing(file, line_number)
  lines = file.is_a?(Array) ? file : file.each_line.to_a

  extract_last_comment(lines[0..(line_number - 2)])
end

#complete_expression?(str) ⇒ Boolean

Determine if a string of code is a complete Ruby expression.

Examples:

complete_expression?("class Hello") #=> false
complete_expression?("class Hello; end") #=> true
complete_expression?("class 123") #=> SyntaxError: unexpected tINTEGER

Raises:

  • (SyntaxError)

    Any SyntaxError that does not represent incompleteness.


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# File 'lib/method_source/code_helpers.rb', line 66

def complete_expression?(str)
  old_verbose = $VERBOSE
  $VERBOSE = nil

  catch(:valid) do
    eval("BEGIN{throw :valid}\n#{str}")
  end

  # Assert that a line which ends with a , or \ is incomplete.
  str !~ /[,\\]\s*\z/
rescue IncompleteExpression
  false
ensure
  $VERBOSE = old_verbose
end

#expression_at(file, line_number, options = {}) ⇒ String

Retrieve the first expression starting on the given line of the given file.

This is useful to get module or method source code.

                      line 1!

Options Hash (options):

  • :strict (Boolean)

    If set to true, then only completely valid expressions are returned. Otherwise heuristics are used to extract expressions that may have been valid inside an eval.

  • :consume (Fixnum)

    A number of lines to automatically consume (add to the expression buffer) without checking for validity.

Raises:

  • (SyntaxError)

    If the first complete expression can't be identified


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# File 'lib/method_source/code_helpers.rb', line 20

def expression_at(file, line_number, options={})
  options = {
    :strict  => false,
    :consume => 0
  }.merge!(options)

  lines = file.is_a?(Array) ? file : file.each_line.to_a

  relevant_lines = lines[(line_number - 1)..-1] || []

  extract_first_expression(relevant_lines, options[:consume])
rescue SyntaxError => e
  raise if options[:strict]

  begin
    extract_first_expression(relevant_lines) do |code|
      code.gsub(/\#\{.*?\}/, "temp")
    end
  rescue SyntaxError
    raise e
  end
end