Class: Prawn::Text::Formatted::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/prawn/text/formatted/parser.rb

Overview

Implements a bi-directional parser between a subset of html and formatted text arrays.

Extension API collapse

PARSER_REGEX =

Parser regular expression.

begin
  regex_string =
    "\n|" \
      '<b>|</b>|' \
      '<i>|</i>|' \
      '<u>|</u>|' \
      '<strikethrough>|</strikethrough>|' \
      '<sub>|</sub>|' \
      '<sup>|</sup>|' \
      '<link[^>]*>|</link>|' \
      '<color[^>]*>|</color>|' \
      '<font[^>]*>|</font>|' \
      '<strong>|</strong>|' \
      '<em>|</em>|' \
      '<a[^>]*>|</a>|' \
      "[^<\n]+"
  Regexp.new(regex_string, Regexp::MULTILINE)
end
ESCAPE_CHARS =

Escaped characters.

{
  '&' => '&amp;',
  '>' => '&gt;',
  '<' => '&lt;',
}.freeze
UNESCAPE_CHARS = 
ESCAPE_CHARS.invert.freeze

Extension API collapse

Class Method Details

.array_from_tokens(tokens) ⇒ Array<Hash>

Parameters:

  • tokens (Array<String>)

Returns:

  • (Array<Hash>) 


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# File 'lib/prawn/text/formatted/parser.rb', line 151

def self.array_from_tokens(tokens)
  array = []
  styles = []
  colors = []
  link = nil
  anchor = nil
  local = nil
  fonts = []
  sizes = []
  character_spacings = []

  tokens.each do |token|
    case token
    when '<b>', '<strong>'
      styles << :bold
    when '<i>', '<em>'
      styles << :italic
    when '<u>'
      styles << :underline
    when '<strikethrough>'
      styles << :strikethrough
    when '<sub>'
      styles << :subscript
    when '<sup>'
      styles << :superscript
    when '</b>', '</strong>'
      styles.delete(:bold)
    when '</i>', '</em>'
      styles.delete(:italic)
    when '</u>'
      styles.delete(:underline)
    when '</strikethrough>'
      styles.delete(:strikethrough)
    when '</sub>'
      styles.delete(:subscript)
    when '</sup>'
      styles.delete(:superscript)
    when '</link>', '</a>'
      link = nil
      anchor = nil
      local = nil
    when '</color>'
      colors.pop
    when '</font>'
      fonts.pop
      sizes.pop
      character_spacings.pop
    when /^<link[^>]*>$/, /^<a[^>]*>$/
      matches = /href="([^"]*)"/.match(token) ||
        /href='([^']*)'/.match(token)
      link = matches[1] unless matches.nil?

      matches = /anchor="([^"]*)"/.match(token) ||
        /anchor='([^']*)'/.match(token)
      anchor = matches[1] unless matches.nil?

      matches = /local="([^"]*)"/.match(token) ||
        /local='([^']*)'/.match(token)
      local = matches[1] unless matches.nil?
    when /^<color[^>]*>$/
      matches = /rgb="#?([^"]*)"/.match(token) ||
        /rgb='#?([^']*)'/.match(token)
      colors << matches[1] if matches

      match = /c="#?([^"]*)"/.match(token) ||
        /c='#?([^']*)'/.match(token)
      c = Integer(match[1], 10) unless match.nil?
      match = /m="#?([^"]*)"/.match(token) ||
        /m='#?([^']*)'/.match(token)
      m = Integer(match[1], 10) unless match.nil?
      match = /y="#?([^"]*)"/.match(token) ||
        /y='#?([^']*)'/.match(token)
      y = Integer(match[1], 10) unless match.nil?
      match = /k="#?([^"]*)"/.match(token) ||
        /k='#?([^']*)'/.match(token)
      k = Integer(match[1], 10) unless match.nil?
      colors << [c, m, y, k] if [c, m, y, k].all?

      # intend to support rgb="#ffffff" or rgb='#ffffff',
      # r="255" g="255" b="255" or r='255' g='255' b='255',
      # and c="100" m="100" y="100" k="100" or
      # c='100' m='100' y='100' k='100'
      # color = { :rgb => "#ffffff" }
      # color = { :r => 255, :g => 255, :b => 255 }
      # color = { :c => 100, :m => 100, :y => 100, :k => 100 }
    when /^<font[^>]*>$/
      matches = /name="([^"]*)"/.match(token) ||
        /name='([^']*)'/.match(token)
      fonts << matches[1] unless matches.nil?

      matches = /size="([^"]*)"/.match(token) ||
        /size='([^']*)'/.match(token)
      sizes << Float(matches[1]) unless matches.nil?

      matches = /character_spacing="([^"]*)"/.match(token) ||
        /character_spacing='([^']*)'/.match(token)
      character_spacings << Float(matches[1]) unless matches.nil?
    else
      string = unescape(token)
      array << {
        text: string,
        styles: styles.dup,
        color: colors.last,
        local: local,
        link: link,
        anchor: anchor,
        font: fonts.last,
        size: sizes.last,
        character_spacing: character_spacings.last,
      }
    end
  end
  array
end

.array_paragraphs(array) ⇒ Array<Array<Hash>>

Break text into paragraphs.

Parameters:

  • array (Array<Hash>) —

    Text fragments.

Returns:

  • (Array<Array<Hash>>) —

    Pragraphs of text fragments.



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# File 'lib/prawn/text/formatted/parser.rb', line 125

def self.array_paragraphs(array)
  paragraphs = []
  paragraph = []
  previous_string = "\n"
  scan_pattern = /[^\n]+|\n/
  array.each do |hash|
    hash[:text].scan(scan_pattern).each do |string|
      if string == "\n"
        if previous_string == "\n"
          paragraph << hash.dup.merge(text: "\n")
        end
        paragraphs << paragraph unless paragraph.empty?
        paragraph = []
      else
        paragraph << hash.dup.merge(text: string)
      end
      previous_string = string
    end
  end
  paragraphs << paragraph unless paragraph.empty?
  paragraphs
end

.escape(text) ⇒ String

Escape characters that can interfere with inline format parsing.

Parameters:

  • text (String)

Returns:

  • (String) 


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# File 'lib/prawn/text/formatted/parser.rb', line 270

def self.escape(text)
  text.gsub(Regexp.union(ESCAPE_CHARS.keys), ESCAPE_CHARS)
end

.format(string, *_args) ⇒ Array<Hash>

Parse formatted string.

Parameters:

  • string (String)

Returns:

  • (Array<Hash>) —

    Text fragments.



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# File 'lib/prawn/text/formatted/parser.rb', line 48

def self.format(string, *_args)
  tokens = string.gsub(%r{<br\s*/?>}, "\n").scan(PARSER_REGEX)
  array_from_tokens(tokens)
end

.to_string(array) ⇒ String

Serialize text fragments to an inline format string.

Parameters:

  • array (Array<Hash>)

Returns:

  • (String) 


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# File 'lib/prawn/text/formatted/parser.rb', line 57

def self.to_string(array)
  prefixes = {
    bold: '<b>',
    italic: '<i>',
    underline: '<u>',
    strikethrough: '<strikethrough>',
    subscript: '<sub>',
    superscript: '<sup>',
  }
  suffixes = {
    bold: '</b>',
    italic: '</i>',
    underline: '</u>',
    strikethrough: '</strikethrough>',
    subscript: '</sub>',
    superscript: '</sup>',
  }
  array
    .map { |hash|
      prefix = ''
      suffix = ''
      hash[:styles]&.each do |style|
        prefix += prefixes[style]
        suffix = suffixes[style] + suffix
      end

      font = hash[:font] ? " name='#{hash[:font]}'" : nil
      size = hash[:size] ? " size='#{hash[:size]}'" : nil
      character_spacing =
        if hash[:character_spacing]
          " character_spacing='#{hash[:character_spacing]}'"
        end
      if font || size || character_spacing
        prefix += "<font#{font}#{size}#{character_spacing}>"
        suffix = '</font>'
      end

      link = hash[:link] ? " href='#{hash[:link]}'" : nil
      anchor = hash[:anchor] ? " anchor='#{hash[:anchor]}'" : nil
      if link || anchor
        prefix += "<link#{link}#{anchor}>"
        suffix = '</link>'
      end

      if hash[:color]
        prefix +=
          if hash[:color].is_a?(Array)
            "<color c='#{hash[:color][0]}' " \
              "m='#{hash[:color][1]}' " \
              "y='#{hash[:color][2]}' " \
              "k='#{hash[:color][3]}'>"
          else
            "<color rgb='#{hash[:color]}'>"
          end
        suffix = '</color>'
      end

      string = escape(hash[:text])
      prefix + string + suffix
    }
    .join
end

.unescape(text) ⇒ String

Unescape characters that can interfere with inline format parsing.

Parameters:

  • text (String)

Returns:

  • (String) 


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# File 'lib/prawn/text/formatted/parser.rb', line 278

def self.unescape(text)
  text.gsub(Regexp.union(UNESCAPE_CHARS.keys), UNESCAPE_CHARS)
end