330 lines
11 KiB
Ruby
330 lines
11 KiB
Ruby
require 'coderay'
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class Pry
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# Load io-console if possible, so that we can use $stdout.winsize.
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begin
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require 'io/console'
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rescue LoadError
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end
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##
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# Pry::Indent is a class that can be used to indent a number of lines
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# containing Ruby code similar as to how IRB does it (but better). The class
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# works by tokenizing a string using CodeRay and then looping over those
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# tokens. Based on the tokens in a line of code that line (or the next one)
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# will be indented or un-indented by correctly.
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#
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class Indent
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include Helpers::BaseHelpers
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# String containing the spaces to be inserted before the next line.
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attr_reader :indent_level
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# The amount of spaces to insert for each indent level.
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SPACES = ' '
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# Hash containing all the tokens that should increase the indentation
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# level. The keys of this hash are open tokens, the values the matching
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# tokens that should prevent a line from being indented if they appear on
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# the same line.
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OPEN_TOKENS = {
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'def' => 'end',
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'class' => 'end',
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'module' => 'end',
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'do' => 'end',
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'if' => 'end',
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'unless' => 'end',
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'while' => 'end',
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'until' => 'end',
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'for' => 'end',
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'case' => 'end',
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'begin' => 'end',
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'[' => ']',
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'{' => '}',
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'(' => ')'
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}
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# Which tokens can either be open tokens, or appear as modifiers on
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# a single-line.
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SINGLELINE_TOKENS = %w(if while until unless rescue)
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# Collection of token types that should be ignored. Without this list
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# keywords such as "class" inside strings would cause the code to be
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# indented incorrectly.
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#
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# :pre_constant and :preserved_constant are the CodeRay 0.9.8 and 1.0.0
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# classifications of "true", "false", and "nil".
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IGNORE_TOKENS = [:space, :content, :string, :method, :ident,
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:constant, :pre_constant, :predefined_constant]
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# Tokens that indicate the end of a statement (i.e. that, if they appear
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# directly before an "if" indicates that that if applies to the same line,
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# not the next line)
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#
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# :reserved and :keywords are the CodeRay 0.9.8 and 1.0.0 respectively
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# classifications of "super", "next", "return", etc.
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STATEMENT_END_TOKENS = IGNORE_TOKENS + [:regexp, :integer, :float, :keyword,
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:delimiter, :reserved]
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# Collection of tokens that should appear dedented even though they
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# don't affect the surrounding code.
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MIDWAY_TOKENS = %w(when else elsif ensure rescue)
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def initialize
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reset
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end
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# reset internal state
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def reset
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@stack = []
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@indent_level = ''
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@heredoc_queue = []
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@close_heredocs = {}
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@string_start = nil
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self
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end
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# Indents a string and returns it. This string can either be a single line
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# or multiple ones.
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#
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# @example
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# str = <<TXT
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# class User
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# attr_accessor :name
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# end
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# TXT
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#
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# # This would result in the following being displayed:
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# #
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# # class User
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# # attr_accessor :name
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# # end
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# #
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# puts Pry::Indent.new.indent(str)
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#
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# @param [String] input The input string to indent.
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# @return [String] The indented version of +input+.
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#
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def indent(input)
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output = ''
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prefix = indent_level
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input.lines.each do |line|
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if in_string?
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tokens = tokenize("#{open_delimiters_line}\n#{line}")
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tokens = tokens.drop_while{ |token, type| !(String === token && token.include?("\n")) }
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previously_in_string = true
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else
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tokens = tokenize(line)
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previously_in_string = false
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end
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before, after = indentation_delta(tokens)
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before.times{ prefix.sub! SPACES, '' }
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new_prefix = prefix + SPACES * after
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line = prefix + line.lstrip unless previously_in_string
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line = line.rstrip + "\n" unless in_string?
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output += line
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prefix = new_prefix
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end
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@indent_level = prefix
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return output.gsub(/\s+$/, '')
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end
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# Get the indentation for the start of the next line.
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#
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# This is what's used between the prompt and the cursor in pry.
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#
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# @return String The correct number of spaces
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#
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def current_prefix
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in_string? ? '' : indent_level
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end
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# Get the change in indentation indicated by the line.
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#
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# By convention, you remove indent from the line containing end tokens,
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# but add indent to the line *after* that which contains the start tokens.
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#
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# This method returns a pair, where the first number is the number of closings
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# on this line (i.e. the number of indents to remove before the line) and the
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# second is the number of openings (i.e. the number of indents to add after
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# this line)
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#
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# @param [Array] tokens A list of tokens to scan.
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# @return [Array[Integer]]
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#
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def indentation_delta(tokens)
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# We need to keep track of whether we've seen a "for" on this line because
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# if the line ends with "do" then that "do" should be discounted (i.e. we're
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# only opening one level not two) To do this robustly we want to keep track
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# of the indent level at which we saw the for, so we can differentiate
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# between "for x in [1,2,3] do" and "for x in ([1,2,3].map do" properly
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seen_for_at = []
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# When deciding whether an "if" token is the start of a multiline statement,
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# or just the middle of a single-line if statement, we just look at the
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# preceding token, which is tracked here.
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last_token, last_kind = [nil, nil]
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# delta keeps track of the total difference from the start of each line after
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# the given token, 0 is just the level at which the current line started for
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# reference.
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remove_before, add_after = [0, 0]
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# If the list of tokens contains a matching closing token the line should
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# not be indented (and thus we should return true).
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tokens.each do |token, kind|
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is_singleline_if = (SINGLELINE_TOKENS.include?(token)) && end_of_statement?(last_token, last_kind)
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is_optional_do = (token == "do" && seen_for_at.include?(add_after - 1))
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last_token, last_kind = token, kind unless kind == :space
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next if IGNORE_TOKENS.include?(kind)
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seen_for_at << add_after if token == "for"
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if kind == :delimiter
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track_delimiter(token)
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elsif OPEN_TOKENS.keys.include?(token) && !is_optional_do && !is_singleline_if
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@stack << token
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add_after += 1
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elsif token == OPEN_TOKENS[@stack.last]
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@stack.pop
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if add_after == 0
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remove_before += 1
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else
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add_after -= 1
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end
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elsif MIDWAY_TOKENS.include?(token)
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if add_after == 0
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remove_before += 1
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add_after += 1
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end
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end
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end
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return [remove_before, add_after]
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end
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# If the code just before an "if" or "while" token on a line looks like the end of a statement,
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# then we want to treat that "if" as a singleline, not multiline statement.
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def end_of_statement?(last_token, last_kind)
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(last_token =~ /^[)\]}\/]$/ || STATEMENT_END_TOKENS.include?(last_kind))
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end
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# Are we currently in the middle of a string literal.
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#
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# This is used to determine whether to re-indent a given line, we mustn't re-indent
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# within string literals because to do so would actually change the value of the
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# String!
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#
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# @return Boolean
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def in_string?
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!open_delimiters.empty?
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end
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# Given a string of Ruby code, use CodeRay to export the tokens.
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#
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# @param String The Ruby to lex.
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# @return [Array] An Array of pairs of [token_value, token_type]
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def tokenize(string)
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tokens = CodeRay.scan(string, :ruby)
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tokens = tokens.tokens.each_slice(2) if tokens.respond_to?(:tokens) # Coderay 1.0.0
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tokens.to_a
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end
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# Update the internal state about what kind of strings are open.
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#
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# Most of the complication here comes from the fact that HEREDOCs can be nested. For
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# normal strings (which can't be nested) we assume that CodeRay correctly pairs
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# open-and-close delimiters so we don't bother checking what they are.
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#
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# @param String The token (of type :delimiter)
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def track_delimiter(token)
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case token
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when /^<<-(["'`]?)(.*)\\1/
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@heredoc_queue << token
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@close_heredocs[token] = /^\s*$2/
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when @close_heredocs[@heredoc_queue.first]
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@heredoc_queue.shift
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else
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if @string_start
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@string_start = nil
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else
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@string_start = token
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end
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end
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end
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# All the open delimiters, in the order that they first appeared.
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#
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# @return [String]
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def open_delimiters
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@heredoc_queue + [@string_start].compact
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end
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# Return a string which restores the CodeRay string status to the correct value by
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# opening HEREDOCs and strings.
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#
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# @return String
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def open_delimiters_line
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"puts #{open_delimiters.join(", ")}"
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end
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# Return a string which, when printed, will rewrite the previous line with
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# the correct indentation. Mostly useful for fixing 'end'.
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#
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# @param [String] prompt The user's prompt
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# @param [String] code The code the user just typed in.
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# @param [Fixnum] overhang (0) The number of chars to erase afterwards (i.e.,
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# the difference in length between the old line and the new one).
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# @return [String]
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def correct_indentation(prompt, code, overhang=0)
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full_line = prompt + code
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whitespace = ' ' * overhang
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_, cols = screen_size
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cols = cols.to_i
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lines = cols != 0 ? (full_line.length / cols + 1) : 1
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if defined?(Win32::Console)
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move_up = "\e[#{lines}F"
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move_down = "\e[#{lines}E"
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else
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move_up = "\e[#{lines}A\e[0G"
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move_down = "\e[#{lines}B\e[0G"
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end
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"#{move_up}#{prompt}#{colorize_code(code)}#{whitespace}#{move_down}"
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end
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# Return a pair of [rows, columns] which gives the size of the window.
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#
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# If the window size cannot be determined, return nil.
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def screen_size
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[
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# io/console adds a winsize method to IO streams.
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$stdout.tty? && $stdout.respond_to?(:winsize) && $stdout.winsize,
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# Some readlines also provides get_screen_size.
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Readline.respond_to?(:get_screen_size) && Readline.get_screen_size,
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# Otherwise try to use the environment (this may be out of date due
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# to window resizing, but it's better than nothing).
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[ENV["ROWS"], ENV["COLUMNS"]]
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].detect do |(_, cols)|
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cols.to_i > 0
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end
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end
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end
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end
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