1
0
Fork 0
mirror of https://github.com/pry/pry.git synced 2022-11-09 12:35:05 -05:00
pry--pry/lib/pry/indent.rb
Conrad Irwin 94e77efa28 Don't rstrip strings [Fixes #657]
Rstripping was there to keep things neat and tidy, unfortunately it's
possible to have some ruby code where whitespace is significant.

I've left the lstripping in because it will not trigger inside a string
and so cannot occlude a closing whitespace delimeter at the start of a
line.
2012-07-18 09:27:43 -07:00

336 lines
11 KiB
Ruby

require 'coderay'
class Pry
# Load io-console if possible, so that we can use $stdout.winsize.
begin
require 'io/console'
rescue LoadError
end
##
# 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.
#
class Indent
include Helpers::BaseHelpers
# @return [String] String containing the spaces to be inserted before the next line.
attr_reader :indent_level
# @return [Array<String>] The stack of open tokens.
attr_reader :stack
# The amount of spaces to insert for each indent level.
SPACES = ' '
# 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.
OPEN_TOKENS = {
'def' => 'end',
'class' => 'end',
'module' => 'end',
'do' => 'end',
'if' => 'end',
'unless' => 'end',
'while' => 'end',
'until' => 'end',
'for' => 'end',
'case' => 'end',
'begin' => 'end',
'[' => ']',
'{' => '}',
'(' => ')'
}
# Which tokens can either be open tokens, or appear as modifiers on
# a single-line.
SINGLELINE_TOKENS = %w(if while until unless rescue)
# 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".
IGNORE_TOKENS = [:space, :content, :string, :method, :ident,
:constant, :pre_constant, :predefined_constant]
# 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.
STATEMENT_END_TOKENS = IGNORE_TOKENS + [:regexp, :integer, :float, :keyword,
:delimiter, :reserved]
# Collection of tokens that should appear dedented even though they
# don't affect the surrounding code.
MIDWAY_TOKENS = %w(when else elsif ensure rescue)
def initialize
reset
end
# reset internal state
def reset
@stack = []
@indent_level = ''
@heredoc_queue = []
@close_heredocs = {}
@string_start = nil
self
end
# 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+.
#
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
output += line
prefix = new_prefix
end
@indent_level = prefix
return output
end
# 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
#
def current_prefix
in_string? ? '' : indent_level
end
# 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[Integer]]
#
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
# 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.
def end_of_statement?(last_token, last_kind)
(last_token =~ /^[)\]}\/]$/ || STATEMENT_END_TOKENS.include?(last_kind))
end
# 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
def in_string?
!open_delimiters.empty?
end
# 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]
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
# 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)
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
# All the open delimiters, in the order that they first appeared.
#
# @return [String]
def open_delimiters
@heredoc_queue + [@string_start].compact
end
# Return a string which restores the CodeRay string status to the correct value by
# opening HEREDOCs and strings.
#
# @return String
def open_delimiters_line
"puts #{open_delimiters.join(", ")}"
end
# 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]
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
# Return a pair of [rows, columns] which gives the size of the window.
#
# If the window size cannot be determined, return nil.
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
end
end