Class: Orgmode::RegexpHelper

Inherits:
Object
  • Object
show all
Defined in:
lib/org-ruby/regexp_helper.rb

Overview

Summary

This class contains helper routines to deal with the Regexp “black magic” you need to properly parse org-mode files.

Key methods

  • Use rewrite_emphasis to replace org-mode emphasis strings (e.g., /italic/) with the suitable markup for the output.

  • Use rewrite_links to get a chance to rewrite all org-mode links with suitable markup for the output.

  • Use rewrite_images to rewrite all inline image links with suitable markup for the output.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ RegexpHelper

Returns a new instance of RegexpHelper.



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# File 'lib/org-ruby/regexp_helper.rb', line 45

def initialize
  # Set up the emphasis regular expression.
  @pre_emphasis = ' \t\(\'"\{'
  @post_emphasis = '- \t\.,:!\?;\'"\)\}\\\\'
  @border_forbidden = '\s,"\''
  @body_regexp = '.*?'
  @max_newlines = 1
  @body_regexp = "#{@body_regexp}" +
                 "(?:\\n#{@body_regexp}){0,#{@max_newlines}}" if @max_newlines > 0
  @markers = '\*\/_=~\+'
  @code_snippet_stack = []
  @logger = Logger.new(STDERR)
  @logger.level = Logger::WARN
  build_org_emphasis_regexp
  build_org_link_regexp
  @org_subp_regexp = /([_^])\{(.*?)\}/
  @org_footnote_regexp = /\[fn:(.+?)(:(.*?))?\]/
end

Instance Attribute Details

#org_image_file_regexp ⇒ Object (readonly)

EMPHASIS

I figure it’s best to stick as closely to the elisp implementation as possible for emphasis. org.el defines the regular expression that is used to apply “emphasis” (in my terminology, inline formatting instead of block formatting). Here’s the documentation from org.el.

Terminology: In an emphasis string like “ *strong word* ”, we call the initial space PREMATCH, the final space POSTMATCH, the stars MARKERS, “s” and “d” are BORDER characters and “trong wor” is the body. The different components in this variable specify what is allowed/forbidden in each part:

pre Chars allowed as prematch. Line beginning allowed, too. post Chars allowed as postmatch. Line end will be allowed too. border The chars forbidden as border characters. body-regexp A regexp like "." to match a body character. Don’t use

non-shy groups here, and don't allow newline here.

newline The maximum number of newlines allowed in an emphasis exp.



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# File 'lib/org-ruby/regexp_helper.rb', line 43

def org_image_file_regexp
  @org_image_file_regexp
end

Instance Method Details

#match_all(str) ⇒ Object

Finds all emphasis matches in a string. Supply a block that will get the marker and body as parameters.



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# File 'lib/org-ruby/regexp_helper.rb', line 66

def match_all(str)
  str.scan(@org_emphasis_regexp) do |match|
    yield $2, $3
  end
end

#restore_code_snippets(str) ⇒ Object 



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# File 'lib/org-ruby/regexp_helper.rb', line 159

def restore_code_snippets str
  str = str % @code_snippet_stack
  @code_snippet_stack = []
  str
end

#rewrite_emphasis(str) ⇒ Object

Compute replacements for all matching emphasized phrases. Supply a block that will get the marker and body as parameters; return the replacement string from your block.

Example

re = RegexpHelper.new
result = re.rewrite_emphasis("*bold*, /italic/, =code=") do |marker, body|
    "<#{map[marker]}>#{body}</#{map[marker]}>"
end

In this example, the block body will get called three times:

  1. Marker: “*”, body: “bold”

  2. Marker: “/”, body: “italic”

  3. Marker: “=”, body: “code”

The return from this block is a string that will be used to replace “bold”, “/italic/”, and “=code=”, respectively. (Clearly this sample string will use HTML-like syntax, assuming map is defined appropriately.)



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# File 'lib/org-ruby/regexp_helper.rb', line 93

def rewrite_emphasis str
  # escape the percent signs for safe restoring code snippets
  str.gsub!(/%/, "%%")
  format_str = "%s"
  str.gsub! @org_emphasis_regexp do |match|
    # preserve the code snippet from further formatting
    inner = if $2 == "=" or $2 == "~"
              @code_snippet_stack.push $3
              yield $2, format_str
            else
              yield $2, $3
            end
    "#{$1}#{inner}"
  end
end

#rewrite_footnote(str) ⇒ Object

rewrite footnotes



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# File 'lib/org-ruby/regexp_helper.rb', line 117

def rewrite_footnote str # :yields: name, definition or nil
  str.gsub! @org_footnote_regexp do |match|
    yield $1, $3
  end
end

#rewrite_links(str) ⇒ Object

Summary

Rewrite org-mode links in a string to markup suitable to the output format.

Usage

Give this a block that expect the link and optional friendly text. Return how that link should get formatted.

Example

re = RegexpHelper.new
result = re.rewrite_links("[[http://www.bing.com]] and [[http://www.hotmail.com][Hotmail]]") do |link, text}
    text ||= link
    "<a href=\"#{link}\">#{text}</a>"
 end

In this example, the block body will get called two times. In the first instance, text will be nil (the org-mode markup gives no friendly text for the link http://www.bing.com. In the second instance, the block will get text of Hotmail and the link http://www.hotmail.com. In both cases, the block returns an HTML-style link, and that is how things will get recorded in result.



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# File 'lib/org-ruby/regexp_helper.rb', line 148

def rewrite_links str # :yields: link, text
  str.gsub! @org_link_regexp do |match|
    yield $1, $3
  end
  str.gsub! @org_angle_link_text_regexp do |match|
    yield $1, nil
  end

  str # for testing
end

#rewrite_subp(str) ⇒ Object

rewrite subscript and superscript (_foo and ^bar)



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# File 'lib/org-ruby/regexp_helper.rb', line 110

def rewrite_subp str # :yields: type ("_" for subscript and "^" for superscript), text
  str.gsub! @org_subp_regexp do |match|
    yield $1, $2
  end
end