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
2012-12-30 18:13:03 -08:00

411 lines
14 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
# Raised if {#module_nesting} would not work.
class UnparseableNestingError < StandardError; end
# @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)
# Which tokens can be followed by an optional "do" keyword.
OPTIONAL_DO_TOKENS = %w(for while until)
# 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)
# Clean the indentation of a fragment of ruby.
#
# @param [String] str
# @return [String]
def self.indent(str)
new.indent(str)
end
# Get the module nesting at the given point in the given string.
#
# NOTE If the line specified contains a method definition, then the nesting
# at the start of the method definition is used. Otherwise the nesting from
# the end of the line is used.
#
# @param [String] str The ruby code to analyze
# @param [Fixnum] line_number The line number (starting from 1)
# @return [Array<String>]
def self.nesting_at(str, line_number)
indent = new
lines = str.split("\n")
n = line_number - 1
to_indent = lines[0...n] + (lines[n] || "").split("def").first(1)
indent.indent(to_indent.join("\n") + "\n")
indent.module_nesting
end
def initialize
reset
end
# reset internal state
def reset
@stack = []
@indent_level = ''
@heredoc_queue = []
@close_heredocs = {}
@string_start = nil
@awaiting_class = false
@module_nesting = []
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)
track_module_nesting(token, kind)
seen_for_at << add_after if OPTIONAL_DO_TOKENS.include?(token)
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]
popped = @stack.pop
track_module_nesting_end(popped)
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
# Update the internal state relating to module nesting.
#
# It's responsible for adding to the @module_nesting array, which looks
# something like:
#
# [ ["class", "Foo"], ["module", "Bar::Baz"], ["class <<", "self"] ]
#
# A nil value in the @module_nesting array happens in two places: either
# when @awaiting_token is true and we're still waiting for the string to
# fill that space, or when a parse was rejected.
#
# At the moment this function is quite restricted about what formats it will
# parse, for example we disallow expressions after the class keyword. This
# could maybe be improved in the future.
#
# @param [String] token a token from Coderay
# @param [Symbol] kind the kind of that token
def track_module_nesting(token, kind)
if kind == :keyword && (token == "class" || token == "module")
@module_nesting << [token, nil]
@awaiting_class = true
elsif @awaiting_class
if kind == :operator && token == "<<" && @module_nesting.last[0] == "class"
@module_nesting.last[0] = "class <<"
@awaiting_class = true
elsif kind == :class && token =~ /\A(self|[A-Z:][A-Za-z0-9_:]*)\z/
@module_nesting.last[1] = token if kind == :class
@awaiting_class = false
else
# leave @nesting[-1][
@awaiting_class = false
end
end
end
# Update the internal state relating to module nesting on 'end'.
#
# If the current 'end' pairs up with a class or a module then we should
# pop an array off of @module_nesting
#
# @param [String] token a token from Coderay
# @param [Symbol] kind the kind of that token
def track_module_nesting_end(token, kind=:keyword)
if kind == :keyword && (token == "class" || token == "module")
@module_nesting.pop
end
end
# Return a list of strings which can be used to re-construct the Module.nesting at
# the current point in the file.
#
# Returns nil if the syntax of the file was not recognizable.
#
# @return [Array<String>]
def module_nesting
@module_nesting.map do |(kind, token)|
raise UnparseableNestingError, @module_nesting.inspect if token.nil?
"#{kind} #{token}"
end
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 = TerminalInfo.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
end
end