----- isHidden: false menupriority: 1 kind: article created_at: 2010-10-26T14:30:58+02:00 title: LaTeX like macro for markdown author_name: Yann Esposito author_uri: yannesposito.com macros: test: "This is a macro test" latex: 'L^aT_eX' # tags: ----- begindiv(intro) <%= tldr %> I made a simple macro system for my blog. Now I juste have to write %latex and it show as %latex. enddiv I added a macro system for my blog system. When we are used to %latex this lack can be hard to handle. Particularly when using mathematical notations. In the header of my files I simply write:


macros:
  test: "This is a macro test"
  latex: 'L^aT_eX'

In the body it will replace every occurrence of: - %test by *%test*, - and %latex by *%latex*. The source code is really simple. For `nanoc` user, simply put this file in your `lib` directory.


# usage:
# ---
# ...
# macros:
#   test: "passed test"
# ---
# ...
# Here is a %test.
#
class Macros < Nanoc3::Filter
    identifier :falacy
    attr_accessor :macro
    def initialize(arg)
        super
        @macro={}
        @macro[:tlal] = %{tlàl : }
        @macro[:tldr] = %{tl;dr: }
        if @item.nil?
            if not arg.nil?
                @macro.merge!( arg )
            end
        else
            if not @item[:macros].nil?
                @macro.merge!( @item[:macros] )
            end
        end
    end
    def macro_value_for(macro_name)
        if macro_name.nil? or macro_name=="" or @macro[macro_name.intern].nil?
            return %{%#{macro_name}} 
        end
        return @macro[macro_name.intern]
    end
    def run(content, params={})
        content.gsub(/%(\w*)/) do |m| 
            if m != '%'
                macro_value_for($1)
            else
                m
            end
        end
    end
end

Macros could be very useful, read [this article](http://adam.gomaa.us/blog/2007/oct/22/markdown-doesnt-scale/index.html) for example.