Parent

Included Modules

Pry::Indent

Pry::Indent is a class that can be used to indent a number of lines containing Ruby code similar as to how IRB does it (but better). The class works by tokenizing a string using CodeRay and then looping over those tokens. Based on the tokens in a line of code that line (or the next one) will be indented or un-indented by correctly.

Constants

IGNORE_TOKENS

Collection of token types that should be ignored. Without this list keywords such as "class" inside strings would cause the code to be indented incorrectly.

:pre_constant and :preserved_constant are the CodeRay 0.9.8 and 1.0.0 classifications of "true", "false", and "nil".

MIDWAY_TOKENS

Collection of tokens that should appear dedented even though they don't affect the surrounding code.

OPEN_TOKENS

Hash containing all the tokens that should increase the indentation level. The keys of this hash are open tokens, the values the matching tokens that should prevent a line from being indented if they appear on the same line.

SINGLELINE_TOKENS

Which tokens can either be open tokens, or appear as modifiers on a single-line.

SPACES

The amount of spaces to insert for each indent level.

STATEMENT_END_TOKENS

Tokens that indicate the end of a statement (i.e. that, if they appear directly before an "if" indicates that that if applies to the same line, not the next line)

:reserved and :keywords are the CodeRay 0.9.8 and 1.0.0 respectively classifications of "super", "next", "return", etc.

Attributes

indent_level[R]

@return [String] String containing the spaces to be inserted before the next line.

stack[R]

@return [Array<String>] The stack of open tokens.

Public Class Methods

new() click to toggle source
# File lib/pry/indent.rb, line 76
def initialize
  reset
end

Public Instance Methods

correct_indentation(prompt, code, overhang=0) click to toggle source

Return a string which, when printed, will rewrite the previous line with the correct indentation. Mostly useful for fixing 'end'.

@param [String] prompt The user's prompt @param [String] code The code the user just typed in. @param [Fixnum] overhang (0) The number of chars to erase afterwards (i.e.,

the difference in length between the old line and the new one).

@return [String]

# File lib/pry/indent.rb, line 293
def correct_indentation(prompt, code, overhang=0)
  full_line = prompt + code
  whitespace = ' ' * overhang

  _, cols = screen_size

  cols = cols.to_i
  lines = cols != 0 ? (full_line.length / cols + 1) : 1

  if Pry::Helpers::BaseHelpers.windows_ansi?
    move_up   = "\e[#{lines}F"
    move_down = "\e[#{lines}E"
  else
    move_up   = "\e[#{lines}A\e[0G"
    move_down = "\e[#{lines}B\e[0G"
  end

  "#{move_up}#{prompt}#{colorize_code(code)}#{whitespace}#{move_down}"
end
current_prefix() click to toggle source

Get the indentation for the start of the next line.

This is what's used between the prompt and the cursor in pry.

@return String The correct number of spaces

# File lib/pry/indent.rb, line 150
def current_prefix
  in_string? ? '' : indent_level
end
end_of_statement?(last_token, last_kind) click to toggle source

If the code just before an "if" or "while" token on a line looks like the end of a statement, then we want to treat that "if" as a singleline, not multiline statement.

# File lib/pry/indent.rb, line 222
def end_of_statement?(last_token, last_kind)
  (last_token =~ /^[)\]}\/]$/ || STATEMENT_END_TOKENS.include?(last_kind))
end
in_string?() click to toggle source

Are we currently in the middle of a string literal.

This is used to determine whether to re-indent a given line, we mustn't re-indent within string literals because to do so would actually change the value of the String!

@return Boolean

# File lib/pry/indent.rb, line 233
def in_string?
  !open_delimiters.empty?
end
indent(input) click to toggle source

Indents a string and returns it. This string can either be a single line or multiple ones.

@example

str = <<TXT
class User
attr_accessor :name
end
TXT

# This would result in the following being displayed:
#
# class User
#   attr_accessor :name
# end
#
puts Pry::Indent.new.indent(str)

@param [String] input The input string to indent. @return [String] The indented version of input.

# File lib/pry/indent.rb, line 111
def indent(input)
  output = ''
  prefix = indent_level

  input.lines.each do |line|

    if in_string?
      tokens = tokenize("#{open_delimiters_line}\n#{line}")
      tokens = tokens.drop_while{ |token, type| !(String === token && token.include?("\n")) }
      previously_in_string = true
    else
      tokens = tokenize(line)
      previously_in_string = false
    end

    before, after = indentation_delta(tokens)

    before.times{ prefix.sub! SPACES, '' }
    new_prefix = prefix + SPACES * after

    line = prefix + line.lstrip unless previously_in_string
    line = line.rstrip + "\n"   unless in_string?

    output += line

    prefix = new_prefix
  end

  @indent_level = prefix

  return output.gsub(/\s+$/, '')
end
indentation_delta(tokens) click to toggle source

Get the change in indentation indicated by the line.

By convention, you remove indent from the line containing end tokens, but add indent to the line after that which contains the start tokens.

This method returns a pair, where the first number is the number of closings on this line (i.e. the number of indents to remove before the line) and the second is the number of openings (i.e. the number of indents to add after this line)

@param [Array] tokens A list of tokens to scan. @return [Array]

# File lib/pry/indent.rb, line 167
def indentation_delta(tokens)

  # We need to keep track of whether we've seen a "for" on this line because
  # if the line ends with "do" then that "do" should be discounted (i.e. we're
  # only opening one level not two) To do this robustly we want to keep track
  # of the indent level at which we saw the for, so we can differentiate
  # between "for x in [1,2,3] do" and "for x in ([1,2,3].map do" properly
  seen_for_at = []

  # When deciding whether an "if" token is the start of a multiline statement,
  # or just the middle of a single-line if statement, we just look at the
  # preceding token, which is tracked here.
  last_token, last_kind = [nil, nil]

  # delta keeps track of the total difference from the start of each line after
  # the given token, 0 is just the level at which the current line started for
  # reference.
  remove_before, add_after = [0, 0]

  # If the list of tokens contains a matching closing token the line should
  # not be indented (and thus we should return true).
  tokens.each do |token, kind|
    is_singleline_if  = (SINGLELINE_TOKENS.include?(token)) && end_of_statement?(last_token, last_kind)
    is_optional_do = (token == "do" && seen_for_at.include?(add_after - 1))

    last_token, last_kind = token, kind unless kind == :space
    next if IGNORE_TOKENS.include?(kind)

    seen_for_at << add_after if token == "for"

    if kind == :delimiter
      track_delimiter(token)
    elsif OPEN_TOKENS.keys.include?(token) && !is_optional_do && !is_singleline_if
      @stack << token
      add_after += 1
    elsif token == OPEN_TOKENS[@stack.last]
      @stack.pop
      if add_after == 0
        remove_before += 1
      else
        add_after -= 1
      end
    elsif MIDWAY_TOKENS.include?(token)
      if add_after == 0
        remove_before += 1
        add_after += 1
      end
    end
  end

  return [remove_before, add_after]
end
open_delimiters() click to toggle source

All the open delimiters, in the order that they first appeared.

@return [String]

# File lib/pry/indent.rb, line 273
def open_delimiters
  @heredoc_queue + [@string_start].compact
end
open_delimiters_line() click to toggle source

Return a string which restores the CodeRay string status to the correct value by opening HEREDOCs and strings.

@return String

# File lib/pry/indent.rb, line 281
def open_delimiters_line
  "puts #{open_delimiters.join(", ")}"
end
reset() click to toggle source

reset internal state

# File lib/pry/indent.rb, line 81
def reset
  @stack = []
  @indent_level = ''
  @heredoc_queue = []
  @close_heredocs = {}
  @string_start = nil
  self
end
screen_size() click to toggle source

Return a pair of [rows, columns] which gives the size of the window.

If the window size cannot be determined, return nil.

# File lib/pry/indent.rb, line 316
def screen_size
  [
     # io/console adds a winsize method to IO streams.
     $stdout.tty? && $stdout.respond_to?(:winsize) && $stdout.winsize,

     # Some readlines also provides get_screen_size.
     Readline.respond_to?(:get_screen_size) && Readline.get_screen_size,

     # Otherwise try to use the environment (this may be out of date due
     # to window resizing, but it's better than nothing).
     [ENV["ROWS"], ENV["COLUMNS"],

     # If the user is running within ansicon, then use the screen size
     # that it reports (same caveats apply as with ROWS and COLUMNS)
     ENV['ANSICON'] =~ /\((.*)x(.*)\)/ && [$2, $1]
    ]
  ].detect do |(_, cols)|
    cols.to_i > 0
  end
end
tokenize(string) click to toggle source

Given a string of Ruby code, use CodeRay to export the tokens.

@param [String] string The Ruby to lex @return [Array] An Array of pairs of [token_value, token_type]

# File lib/pry/indent.rb, line 241
def tokenize(string)
  tokens = CodeRay.scan(string, :ruby)
  tokens = tokens.tokens.each_slice(2) if tokens.respond_to?(:tokens) # Coderay 1.0.0
  tokens.to_a
end
track_delimiter(token) click to toggle source

Update the internal state about what kind of strings are open.

Most of the complication here comes from the fact that HEREDOCs can be nested. For normal strings (which can't be nested) we assume that CodeRay correctly pairs open-and-close delimiters so we don't bother checking what they are.

@param [String] token The token (of type :delimiter)

# File lib/pry/indent.rb, line 254
def track_delimiter(token)
  case token
  when /^<<-(["'`]?)(.*)\\1/
    @heredoc_queue << token
    @close_heredocs[token] = /^\s*$2/
  when @close_heredocs[@heredoc_queue.first]
    @heredoc_queue.shift
  else
    if @string_start
      @string_start = nil
    else
      @string_start = token
    end
  end
end

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