Class: Mustache::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/mustache/generator.rb

Overview

The Generator is in charge of taking an array of Mustache tokens, usually assembled by the Parser, and generating an interpolatable Ruby string. This string is considered the “compiled” template because at that point we’re relying on Ruby to do the parsing and run our code.

For example, let’s take this template:

Hi {{thing}}!

If we run this through the Parser we’ll get these tokens:

[:multi,
  [:static, "Hi "],
  [:mustache, :etag, "thing"],
  [:static, "!\n"]]

Now let’s hand that to the Generator:

>> puts Mustache::Generator.new.compile(tokens) “Hi #.to_s)!n”

You can see the generated Ruby string for any template with the mustache(1) command line tool:

$ mustache --compile test.mustache
"Hi #{CGI.escapeHTML(ctx[:thing].to_s)}!\n"

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Generator

Options are unused for now but may become useful in the future.



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# File 'lib/mustache/generator.rb', line 31

def initialize(options = {})
  @options = options
end

Instance Method Details

#compile(exp) ⇒ Object

Given an array of tokens, returns an interpolatable Ruby string.



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# File 'lib/mustache/generator.rb', line 36

def compile(exp)
  "\"#{compile!(exp)}\""
end

#compile!(exp) ⇒ Object

Given an array of tokens, converts them into Ruby code. In particular there are three types of expressions we are concerned with:

:multi
  Mixed bag of :static, :mustache, and whatever.

:static
  Normal HTML, the stuff outside of {{mustaches}}.

:mustache
  Any Mustache tag, from sections to partials.

To give you an idea of what you’ll be dealing with take this template:

Hello {{name}}
You have just won ${{value}}!
{{#in_ca}}
Well, ${{taxed_value}}, after taxes.
{{/in_ca}}

If we run this through the Parser, we’ll get back this array of tokens:

[:multi,
 [:static, "Hello "],
 [:mustache, :etag, "name"],
 [:static, "\nYou have just won $"],
 [:mustache, :etag, "value"],
 [:static, "!\n"],
 [:mustache,
  :section,
  "in_ca",
  [:multi,
   [:static, "Well, $"],
   [:mustache, :etag, "taxed_value"],
   [:static, ", after taxes.\n"]]]]



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# File 'lib/mustache/generator.rb', line 78

def compile!(exp)
  case exp.first
  when :multi
    exp[1..-1].map { |e| compile!(e) }.join
  when :static
    str(exp[1])
  when :mustache
    send("on_#{exp[1]}", *exp[2..-1])
  else
    raise "Unhandled exp: #{exp.first}"
  end
end

#ev(s) ⇒ Object

An interpolation-friendly version of a string, for use within a Ruby string.



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# File 'lib/mustache/generator.rb', line 150

def ev(s)
  "#\{#{s}}"
end

#on_etag(name) ⇒ Object

An escaped tag.



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# File 'lib/mustache/generator.rb', line 144

def on_etag(name)
  ev("CGI.escapeHTML(ctx[#{name.to_sym.inspect}].to_s)")
end

#on_inverted_section(name, content) ⇒ Object

Fired when we find an inverted section. Just like ‘on_section`, we’re passed the inverted section name and the array of tokens.



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# File 'lib/mustache/generator.rb', line 116

def on_inverted_section(name, content)
  # Convert the tokenized content of this section into a Ruby
  # string we can use.
  code = compile(content)

  # Compile the Ruby for this inverted section now that we know
  # what's inside.
  ev(<<-compiled)
  v = ctx[#{name.to_sym.inspect}]
  if v.nil? || v == false || v.respond_to?(:empty?) && v.empty?
    #{code}
  end
  compiled
end

#on_partial(name) ⇒ Object

Fired when the compiler finds a partial. We want to return code which calls a partial at runtime instead of expanding and including the partial’s body to allow for recursive partials.



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# File 'lib/mustache/generator.rb', line 134

def on_partial(name)
  ev("ctx.partial(#{name.to_sym.inspect})")
end

#on_section(name, content) ⇒ Object

Callback fired when the compiler finds a section token. We’re passed the section name and the array of tokens.



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# File 'lib/mustache/generator.rb', line 93

def on_section(name, content)
  # Convert the tokenized content of this section into a Ruby
  # string we can use.
  code = compile(content)

  # Compile the Ruby for this section now that we know what's
  # inside the section.
  ev(<<-compiled)
  if v = ctx[#{name.to_sym.inspect}]
    if v == true
      #{code}
    elsif v.is_a?(Proc)
      v.call(#{code})
    else
      v = [v] unless v.is_a?(Array) # shortcut when passed non-array
      v.map { |h| ctx.push(h); r = #{code}; ctx.pop; r }.join
    end
  end
  compiled
end

#on_utag(name) ⇒ Object

An unescaped tag.



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# File 'lib/mustache/generator.rb', line 139

def on_utag(name)
  ev("ctx[#{name.to_sym.inspect}]")
end

#str(s) ⇒ Object 



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# File 'lib/mustache/generator.rb', line 154

def str(s)
  s.inspect[1..-2]
end