Module: Repper::Codemod

Defined in:
lib/repper/codemod.rb

Overview

Formatter for Ruby code containing Regexp literals

Defined Under Namespace

Classes: Location

Class Method Summary collapse

Class Method Details

.call(code) ⇒ Object 



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# File 'lib/repper/codemod.rb', line 6

def call(code)
  formatted_code = code.dup

  regexp_locations(code).reverse.each do |loc|
    beg_idx = code[/\A(.*\n){#{loc.beg_line}}/].size + loc.beg_char
    end_idx = code[/\A(.*\n){#{loc.end_line}}/].size + loc.end_char
    range = beg_idx..end_idx

    /\A(?<start>\/|%r.)(?<source>.*)(?<stop>[^a-z])(?<flags>[a-z]*)\z/m =~
      code[range]

    tokens = Tokenizer.call(source, delimiters: [start, stop], flags: flags)
    formatted_regexp = Format::Extended.call(tokens, Theme::Plain)

    # indent consistently by applying leading line indentation to all lines
    lead_indentation = code.lines[loc.beg_line][/^ */]
    formatted_regexp.gsub!("\n", "\n#{lead_indentation}")

    formatted_code[range] = formatted_regexp
  end

  formatted_code
end

.regexp_locations(code) ⇒ Object 



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# File 'lib/repper/codemod.rb', line 32

def regexp_locations(code)
  embed_level = 0
  beg_tokens = {}

  Ripper.lex(code).each.with_object([]) do |token, acc|
    case token[1]
    when :on_regexp_beg
      beg_tokens[embed_level] = token
      # nested regexp literals are not supported a.t.m., so if we're
      # in an embed, discard the location of the surrounding regexp.
      beg_tokens[embed_level - 1] = nil
    when :on_regexp_end
      next unless beg_token = beg_tokens[embed_level]

      acc << Location.new(
        beg_line: beg_token[0][0] - 1, # note: using 0-indexed line values
        beg_char: beg_token[0][1],
        end_line: token[0][0] - 1,
        end_char: token[0][1] + (token[2].length - 1), # lex includes flags
      )
    when :on_embexpr_beg # embedded expression a.k.a. interpolation (#{...})
      embed_level += 1
    when :on_embexpr_end
      embed_level -= 1
    when :on_const, :on_ident
      # OK when embedded - Regexp::Parser will treat them as literals
    else
      # other embedded expressions are not supported
      beg_tokens[embed_level - 1] = nil
    end
  end
end