Module: Ferb

Defined in:
lib/ferb.rb

Overview

This is a mixin module that makes it easy to define methods on a class that are expanded using an ERB template

Author

Jim Powers ([email protected])

Copyright

Copyright © 2008-2009 Jim Powers

License

Distributed under the terms of the LGPLv3.0 or newer.

For details see the LGPL30 file

Example:

class Foo

require 'ferb'
include Ferb

def_template("hello_world(m)","<b><%= m %></b>")

end

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.build_internal_template(signature, body) ⇒ Object 



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# File 'lib/ferb.rb', line 48

def self.build_internal_template(signature,body)
  body_rb = ERB.new(body,nil,'-').src
  <<EOS
def __ferb_#{signature}
#{body_rb}
end
EOS
end

.build_template(signature, clean_sig, source_file_data = nil, function = nil) ⇒ Object

Builds a string representing the definition of the function



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# File 'lib/ferb.rb', line 59

def self.build_template(signature, clean_sig, source_file_data = nil, function = nil)
  unless source_file_data
  <<EOS
def #{signature}
__ferb_#{clean_sig}
end
EOS
  else
  <<EOS
def #{signature}
if Ferb.enable_reload?
  full_path = '#{source_file_data[:full_path]}'
  signature = '#{function}'
  if should_reload?(full_path)
    args = {:path => full_path}
    template = Ferb.load_template(args)
    add_timestamp(args[:full_path], args[:timestamp])
    internal_func = Ferb.construct_internal_function_def(signature,template)
    eval(internal_func)
  end
end
__ferb_#{clean_sig}
end
EOS
  end
end

.construct_function_def(function, template, args = nil) ⇒ Object 



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# File 'lib/ferb.rb', line 134

def self.construct_function_def(function, template, args = nil)
  parts = get_template_parts(template)
  funsig = nil
  clean_sig = nil
  if parts.is_a?(Array)
    funsig, clean_sig = construct_function_sig(function,parts[0])
  else
    funsig = function
  end
  build_template(funsig, clean_sig, args, function)
end

.construct_function_sig(function, sig) ⇒ Object 



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# File 'lib/ferb.rb', line 125

def self.construct_function_sig(function, sig)
  sig = sig.strip
  if !sig.empty?
    ["#{function.to_s.strip}(#{sig})", "#{function.to_s.strip}(#{MethodArgsHelper.get_args(sig).join(',')})"]
  else
    [function.to_s.strip, nil]
  end
end

.construct_internal_function_def(function, template) ⇒ Object 



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# File 'lib/ferb.rb', line 146

def self.construct_internal_function_def(function, template)
  parts = get_template_parts(template)
  funsig = nil
  clean_sig = nil
  body = nil
  if parts.is_a?(Array)
    funsig, clean_sig = construct_function_sig(function,parts[0])
    body = parts[1]
  else
    funsig = function
    body = template
  end
  build_internal_template(funsig, body)
end

.enable_reload=(val) ⇒ Object

Enables support for reloading file templates at run-time if the file timestamp has changed



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# File 'lib/ferb.rb', line 37

def self.enable_reload=(val)
  @@enable_reload = val
end

.enable_reload? ⇒ Boolean

Enables support for reloading file templates at run-time if the file timestamp has changed

Returns:

  • (Boolean) 


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# File 'lib/ferb.rb', line 27

def self.enable_reload?
  if defined?(@@enable_reload)
    return @@enable_reload
  else
    return false
  end
end

.get_template_parts(template) ⇒ Object 



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# File 'lib/ferb.rb', line 109

def self.get_template_parts(template)
  result = nil
  if template and !template.strip.empty?
    strio = StringIO.new(template)
    first_line = strio.readline
    if first_line.strip =~ /^<!--.*\|(.*)\|.*-->$/
      sig = $1
      body = strio.read
      result = [sig, body]
    else
      body = template
    end
  end
  result
end

.included(base) ⇒ Object

The “callback” when this module is included by a class. Extends the class with the metods defined in the inner ‘ClassMethods’ module



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# File 'lib/ferb.rb', line 44

def self.included(base)
  base.extend(ClassMethods)
end

.load_template(args) ⇒ Object 



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# File 'lib/ferb.rb', line 86

def self.load_template(args)
  result = nil
  path = nil
  if args.has_key?(:path)
    path = Pathname.new(args[:path].to_s.strip)
  elsif args.has_key?(:file)
    template_root = args[:template_root]
    unless template_root.is_a?(Pathname)
      template_root = Pathname.new(args[:template_root].to_s)
    end
    args[:template_root] = template_root
    path = template_root+args[:file]
  else
    raise(":file or :path not specified: #{args.inspect}")
  end
  args[:full_path] = path.realpath
  args[:timestamp] = path.mtime
  path.open do |f|
    result = f.read
  end
  result
end

Instance Method Details

#add_timestamp(path, time) ⇒ Object

Record file timestamps



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# File 'lib/ferb.rb', line 241

def add_timestamp(path, time)
  self.file_timestamps[path] = time
end

#def_template(signature, args) ⇒ Object

Defines a template function in an individual object (only available to a prticular instance) as an instance method. Creates the method directly on the object (instance).

Arguments:

<tt>signature</tt> - (string) The complete signature including parameters
<tt>body</tt> - (string) The body of the functionusing ERB syntax

Example:

obj.def_template(“hello_world(message)”,“<%= message %>”)



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# File 'lib/ferb.rb', line 286

def def_template(signature,args)
  if args.is_a?(String)
    internal_func = Ferb.construct_internal_function_def(signature,args)
    external_func = Ferb.construct_function_def(signature,args)
    eval(internal_func)
    eval(external_func)
  elsif args.is_a?(Hash)
    args = { :template_root => template_root}.merge(args)
    template = Ferb.load_template(args)
    add_timestamp(args[:full_path], args[:timestamp])
    internal_func = Ferb.construct_internal_function_def(signature,template)
    external_func = Ferb.construct_function_def(signature,template,args)
    eval(internal_func)
    eval(external_func)
  end
end

#file_timestamps ⇒ Object 



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# File 'lib/ferb.rb', line 233

def file_timestamps
  unless defined?(@file_timestamps)
    @file_timestamps = {}
  end
  @file_timestamps
end

#should_reload?(path) ⇒ Boolean

Test file timestamps

Returns:

  • (Boolean) 


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# File 'lib/ferb.rb', line 246

def should_reload?(path)
  time = Pathname.new(path).mtime
  ts = self.file_timestamps[path]
  if ts and (ts >= time)
    return false;
  else
    return true
  end
end

#template_root ⇒ Object

Returns the root in the file system where ERB templates can be found



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# File 'lib/ferb.rb', line 257

def template_root
  if !defined?(@template_root)
    if self.class.respond_to?(:template_root)
      @template_root = self.class.template_root
    else
      @template_root = Pathname.new(File.expand_path(File.dirname(__FILE__)))
    end
  end
  @template_root
end

#template_root=(location) ⇒ Object

Sets the root in the file system where ERB templates can be found



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# File 'lib/ferb.rb', line 269

def template_root=(location)
  @template_root = Pathname.new(File.expand_path(location))
end