# = ERB -- Ruby Templating
#
# Author:: Masatoshi SEKI
# Documentation:: James Edward Gray II and Gavin Sinclair
#
# See ERB for primary documentation and ERB::Util for a couple of utility
# routines.
#
# Copyright (c) 1999-2000,2002,2003 Masatoshi SEKI
#
# You can redistribute it and/or modify it under the same terms as Ruby.
#
# = ERB -- Ruby Templating
#
# == Introduction
#
# ERB provides an easy to use but powerful templating system for Ruby. Using
# ERB, actual Ruby code can be added to any plain text document for the
# purposes of generating document information details and/or flow control.
#
# A very simple example is this:
#
# require 'erb'
#
# x = 42
# template = ERB.new <<-EOF
# The value of x is: <%= x %>
# EOF
# puts template.result(binding)
#
# <em>Prints:</em> The value of x is: 42
#
# More complex examples are given below.
#
#
# == Recognized Tags
#
# ERB recognizes certain tags in the provided template and converts them based
# on the rules below:
#
# <% Ruby code -- inline with output %>
# <%= Ruby expression -- replace with result %>
# <%# comment -- ignored -- useful in testing %>
# % a line of Ruby code -- treated as <% line %> (optional -- see ERB.new)
# %% replaced with % if first thing on a line and % processing is used
# <%% or %%> -- replace with <% or %> respectively
#
# All other text is passed through ERB filtering unchanged.
#
#
# == Options
#
# There are several settings you can change when you use ERB:
# * the nature of the tags that are recognized;
# * the value of <tt>$SAFE</tt> under which the template is run;
# * the binding used to resolve local variables in the template.
#
# See the ERB.new and ERB#result methods for more detail.
#
#
# == Examples
#
# === Plain Text
#
# ERB is useful for any generic templating situation. Note that in this example, we use the
# convenient "% at start of line" tag, and we quote the template literally with
# <tt>%q{...}</tt> to avoid trouble with the backslash.
#
# require "erb"
#
# # Create template.
# template = %q{
# From: James Edward Gray II <james@grayproductions.net>
# To: <%= to %>
# Subject: Addressing Needs
#
# <%= to[/\w+/] %>:
#
# Just wanted to send a quick note assuring that your needs are being
# addressed.
#
# I want you to know that my team will keep working on the issues,
# especially:
#
# <%# ignore numerous minor requests -- focus on priorities %>
# % priorities.each do |priority|
# * <%= priority %>
# % end
#
# Thanks for your patience.
#
# James Edward Gray II
# }.gsub(/^ /, '')
#
# message = ERB.new(template, 0, "%<>")
#
# # Set up template data.
# to = "Community Spokesman <spokesman@ruby_community.org>"
# priorities = [ "Run Ruby Quiz",
# "Document Modules",
# "Answer Questions on Ruby Talk" ]
#
# # Produce result.
# email = message.result
# puts email
#
# <i>Generates:</i>
#
# From: James Edward Gray II <james@grayproductions.net>
# To: Community Spokesman <spokesman@ruby_community.org>
# Subject: Addressing Needs
#
# Community:
#
# Just wanted to send a quick note assuring that your needs are being addressed.
#
# I want you to know that my team will keep working on the issues, especially:
#
# * Run Ruby Quiz
# * Document Modules
# * Answer Questions on Ruby Talk
#
# Thanks for your patience.
#
# James Edward Gray II
#
# === Ruby in HTML
#
# ERB is often used in <tt>.rhtml</tt> files (HTML with embedded Ruby). Notice the need in
# this example to provide a special binding when the template is run, so that the instance
# variables in the Product object can be resolved.
#
# require "erb"
#
# # Build template data class.
# class Product
# def initialize( code, name, desc, cost )
# @code = code
# @name = name
# @desc = desc
# @cost = cost
#
# @features = [ ]
# end
#
# def add_feature( feature )
# @features << feature
# end
#
# # Support templating of member data.
# def get_binding
# binding
# end
#
# # ...
# end
#
# # Create template.
# template = %{
# <html>
# <head><title>Ruby Toys -- <%= @name %></title></head>
# <body>
#
# <h1><%= @name %> (<%= @code %>)</h1>
# <p><%= @desc %></p>
#
# <ul>
# <% @features.each do |f| %>
# <li><b><%= f %></b></li>
# <% end %>
# </ul>
#
# <p>
# <% if @cost < 10 %>
# <b>Only <%= @cost %>!!!</b>
# <% else %>
# Call for a price, today!
# <% end %>
# </p>
#
# </body>
# </html>
# }.gsub(/^ /, '')
#
# rhtml = ERB.new(template)
#
# # Set up template data.
# toy = Product.new( "TZ-1002",
# "Rubysapien",
# "Geek's Best Friend! Responds to Ruby commands...",
# 999.95 )
# toy.add_feature("Listens for verbal commands in the Ruby language!")
# toy.add_feature("Ignores Perl, Java, and all C variants.")
# toy.add_feature("Karate-Chop Action!!!")
# toy.add_feature("Matz signature on left leg.")
# toy.add_feature("Gem studded eyes... Rubies, of course!")
#
# # Produce result.
# rhtml.run(toy.get_binding)
#
# <i>Generates (some blank lines removed):</i>
#
# <html>
# <head><title>Ruby Toys -- Rubysapien</title></head>
# <body>
#
# <h1>Rubysapien (TZ-1002)</h1>
# <p>Geek's Best Friend! Responds to Ruby commands...</p>
#
# <ul>
# <li><b>Listens for verbal commands in the Ruby language!</b></li>
# <li><b>Ignores Perl, Java, and all C variants.</b></li>
# <li><b>Karate-Chop Action!!!</b></li>
# <li><b>Matz signature on left leg.</b></li>
# <li><b>Gem studded eyes... Rubies, of course!</b></li>
# </ul>
#
# <p>
# Call for a price, today!
# </p>
#
# </body>
# </html>
#
#
# == Notes
#
# There are a variety of templating solutions available in various Ruby projects:
# * ERB's big brother, eRuby, works the same but is written in C for speed;
# * Amrita (smart at producing HTML/XML);
# * cs/Template (written in C for speed);
# * RDoc, distributed with Ruby, uses its own template engine, which can be reused elsewhere;
# * and others; search the RAA.
#
# Rails, the web application framework, uses ERB to create views.
#
class ERB
Revision = '$Date: 2004/11/25 16:04:24 $' #'
# Returns revision information for the erb.rb module.
def self.version
"erb.rb [2.0.4 #{ERB::Revision.split[1]}]"
end
end
#--
# ERB::Compiler
class ERB
class Compiler # :nodoc:
class PercentLine # :nodoc:
def initialize(str)
@value = str
end
attr_reader :value
alias :to_s :value
end
class Scanner # :nodoc:
SplitRegexp = /(<%%)|(%%>)|(<%=)|(<%#)|(<%)|(%>)|(\n)/
@scanner_map = {}
def self.regist_scanner(klass, trim_mode, percent)
@scanner_map[[trim_mode, percent]] = klass
end
def self.default_scanner=(klass)
@default_scanner = klass
end
def self.make_scanner(src, trim_mode, percent)
klass = @scanner_map.fetch([trim_mode, percent], @default_scanner)
klass.new(src, trim_mode, percent)
end
def initialize(src, trim_mode, percent)
@src = src
@stag = nil
end
attr_accessor :stag
def scan; end
end
class TrimScanner < Scanner # :nodoc:
TrimSplitRegexp = /(<%%)|(%%>)|(<%=)|(<%#)|(<%)|(%>\n)|(%>)|(\n)/
def initialize(src, trim_mode, percent)
super
@trim_mode = trim_mode
@percent = percent
if @trim_mode == '>'
@scan_line = self.method(:trim_line1)
elsif @trim_mode == '<>'
@scan_line = self.method(:trim_line2)
elsif @trim_mode == '-'
@scan_line = self.method(:explicit_trim_line)
else
@scan_line = self.method(:scan_line)
end
end
attr_accessor :stag
def scan(&block)
@stag = nil
if @percent
@src.each do |line|
percent_line(line, &block)
end
else
@src.each do |line|
@scan_line.call(line, &block)
end
end
nil
end
def percent_line(line, &block)
if @stag || line[0] != ?%
return @scan_line.call(line, &block)
end
line[0] = ''
if line[0] == ?%
@scan_line.call(line, &block)
else
yield(PercentLine.new(line.chomp))
end
end
def scan_line(line)
line.split(SplitRegexp).each do |token|
next if token.empty?
yield(token)
end
end
def trim_line1(line)
line.split(TrimSplitRegexp).each do |token|
next if token.empty?
if token == "%>\n"
yield('%>')
yield(:cr)
break
end
yield(token)
end
end
def trim_line2(line)
head = nil
line.split(TrimSplitRegexp).each do |token|
next if token.empty?
head = token unless head
if token == "%>\n"
yield('%>')
if is_erb_stag?(head)
yield(:cr)
else
yield("\n")
end
break
end
yield(token)
end
end
ExplicitTrimRegexp = /(^[ \t]*<%-)|(-%>\n?\z)|(<%-)|(-%>)|(<%%)|(%%>)|(<%=)|(<%#)|(<%)|(%>)|(\n)/
def explicit_trim_line(line)
line.split(ExplicitTrimRegexp).each do |token|
next if token.empty?
if @stag.nil? && /[ \t]*<%-/ =~ token
yield('<%')
elsif @stag && /-%>\n/ =~ token
yield('%>')
yield(:cr)
elsif @stag && token == '-%>'
yield('%>')
else
yield(token)
end
end
end
ERB_STAG = %w(<%= <%# <%)
def is_erb_stag?(s)
ERB_STAG.member?(s)
end
end
Scanner.default_scanner = TrimScanner
class SimpleScanner < Scanner # :nodoc:
def scan
@src.each do |line|
line.split(SplitRegexp).each do |token|
next if token.empty?
yield(token)
end
end
end
end
Scanner.regist_scanner(SimpleScanner, nil, false)
begin
require 'strscan'
class SimpleScanner2 < Scanner # :nodoc:
def scan
stag_reg = /(.*?)(<%%|<%=|<%#|<%|\n|\z)/
etag_reg = /(.*?)(%%>|%>|\n|\z)/
scanner = StringScanner.new(@src)
while ! scanner.eos?
scanner.scan(@stag ? etag_reg : stag_reg)
text = scanner[1]
elem = scanner[2]
yield(text) unless text.empty?
yield(elem) unless elem.empty?
end
end
end
Scanner.regist_scanner(SimpleScanner2, nil, false)
class PercentScanner < Scanner # :nodoc:
def scan
new_line = true
stag_reg = /(.*?)(<%%|<%=|<%#|<%|\n|\z)/
etag_reg = /(.*?)(%%>|%>|\n|\z)/
scanner = StringScanner.new(@src)
while ! scanner.eos?
if new_line && @stag.nil?
if scanner.scan(/%%/)
yield('%')
new_line = false
next
elsif scanner.scan(/%/)
yield(PercentLine.new(scanner.scan(/.*?(\n|\z)/).chomp))
next
end
end
scanner.scan(@stag ? etag_reg : stag_reg)
text = scanner[1]
elem = scanner[2]
yield(text) unless text.empty?
yield(elem) unless elem.empty?
new_line = (elem == "\n")
end
end
end
Scanner.regist_scanner(PercentScanner, nil, true)
class ExplicitScanner < Scanner # :nodoc:
def scan
new_line = true
stag_reg = /(.*?)(<%%|<%=|<%#|<%-|<%|\n|\z)/
etag_reg = /(.*?)(%%>|-%>|%>|\n|\z)/
scanner = StringScanner.new(@src)
while ! scanner.eos?
if new_line && @stag.nil? && scanner.scan(/[ \t]*<%-/)
yield('<%')
new_line = false
next
end
scanner.scan(@stag ? etag_reg : stag_reg)
text = scanner[1]
elem = scanner[2]
new_line = (elem == "\n")
yield(text) unless text.empty?
if elem == '-%>'
yield('%>')
if scanner.scan(/(\n|\z)/)
yield(:cr)
new_line = true
end
elsif elem == '<%-'
yield('<%')
else
yield(elem) unless elem.empty?
end
end
end
end
Scanner.regist_scanner(ExplicitScanner, '-', false)
rescue LoadError
end
class Buffer # :nodoc:
def initialize(compiler)
@compiler = compiler
@line = []
@script = ""
@compiler.pre_cmd.each do |x|
push(x)
end
end
attr_reader :script
def push(cmd)
@line << cmd
end
def cr
@script << (@line.join('; '))
@line = []
@script << "\n"
end
def close
return unless @line
@compiler.post_cmd.each do |x|
push(x)
end
@script << (@line.join('; '))
@line = nil
end
end
def compile(s)
out = Buffer.new(self)
content = ''
scanner = make_scanner(s)
scanner.scan do |token|
if scanner.stag.nil?
case token
when PercentLine
out.push("#{@put_cmd} #{content.dump}") if content.size > 0
content = ''
out.push(token.to_s)
out.cr
when :cr
out.cr
when '<%', '<%=', '<%#'
scanner.stag = token
out.push("#{@put_cmd} #{content.dump}") if content.size > 0
content = ''
when "\n"
content << "\n"
out.push("#{@put_cmd} #{content.dump}")
out.cr
content = ''
when '<%%'
content << '<%'
else
content << token
end
else
case token
when '%>'
case scanner.stag
when '<%'
if content[-1] == ?\n
content.chop!
out.push(content)
out.cr
else
out.push(content)
end
when '<%='
out.push("#{@put_cmd}((#{content}).to_s)")
when '<%#'
# out.push("# #{content.dump}")
end
scanner.stag = nil
content = ''
when '%%>'
content << '%>'
else
content << token
end
end
end
out.push("#{@put_cmd} #{content.dump}") if content.size > 0
out.close
out.script
end
def prepare_trim_mode(mode)
case mode
when 1
return [false, '>']
when 2
return [false, '<>']
when 0
return [false, nil]
when String
perc = mode.include?('%')
if mode.include?('-')
return [perc, '-']
elsif mode.include?('<>')
return [perc, '<>']
elsif mode.include?('>')
return [perc, '>']
else
[perc, nil]
end
else
return [false, nil]
end
end
def make_scanner(src)
Scanner.make_scanner(src, @trim_mode, @percent)
end
def initialize(trim_mode)
@percent, @trim_mode = prepare_trim_mode(trim_mode)
@put_cmd = 'print'
@pre_cmd = []
@post_cmd = []
end
attr_reader :percent, :trim_mode
attr_accessor :put_cmd, :pre_cmd, :post_cmd
end
end
#--
# ERB
class ERB
#
# Constructs a new ERB object with the template specified in _str_.
#
# An ERB object works by building a chunk of Ruby code that will output
# the completed template when run. If _safe_level_ is set to a non-nil value,
# ERB code will be run in a separate thread with <b>$SAFE</b> set to the
# provided level.
#
# If _trim_mode_ is passed a String containing one or more of the following
# modifiers, ERB will adjust its code generation as listed:
#
# % enables Ruby code processing for lines beginning with %
# <> omit newline for lines starting with <% and ending in %>
# > omit newline for lines ending in %>
#
# _eoutvar_ can be used to set the name of the variable ERB will build up
# its output in. This is useful when you need to run multiple ERB
# templates through the same binding and/or when you want to control where
# output ends up. Pass the name of the variable to be used inside a String.
#
# === Example
#
# require "erb"
#
# # build data class
# class Listings
# PRODUCT = { :name => "Chicken Fried Steak",
# :desc => "A well messages pattie, breaded and fried.",
# :cost => 9.95 }
#
# attr_reader :product, :price
#
# def initialize( product = "", price = "" )
# @product = product
# @price = price
# end
#
# def build
# b = binding
# # create and run templates, filling member data variebles
# ERB.new(<<-'END_PRODUCT'.gsub(/^\s+/, ""), 0, "", "@product").result b
# <%= PRODUCT[:name] %>
# <%= PRODUCT[:desc] %>
# END_PRODUCT
# ERB.new(<<-'END_PRICE'.gsub(/^\s+/, ""), 0, "", "@price").result b
# <%= PRODUCT[:name] %> -- <%= PRODUCT[:cost] %>
# <%= PRODUCT[:desc] %>
# END_PRICE
# end
# end
#
# # setup template data
# listings = Listings.new
# listings.build
#
# puts listings.product + "\n" + listings.price
#
# _Generates_
#
# Chicken Fried Steak
# A well messages pattie, breaded and fried.
#
# Chicken Fried Steak -- 9.95
# A well messages pattie, breaded and fried.
#
def initialize(str, safe_level=nil, trim_mode=nil, eoutvar='_erbout')
@safe_level = safe_level
compiler = ERB::Compiler.new(trim_mode)
set_eoutvar(compiler, eoutvar)
@src = compiler.compile(str)
@filename = nil
end
# The Ruby code generated by ERB
attr_reader :src
# The optional _filename_ argument passed to Kernel#eval when the ERB code
# is run
attr_accessor :filename
#
# Can be used to set _eoutvar_ as described in ERB#new. It's probably easier
# to just use the constructor though, since calling this method requires the
# setup of an ERB _compiler_ object.
#
def set_eoutvar(compiler, eoutvar = '_erbout')
compiler.put_cmd = "#{eoutvar}.concat"
cmd = []
cmd.push "#{eoutvar} = ''"
compiler.pre_cmd = cmd
cmd = []
cmd.push(eoutvar)
compiler.post_cmd = cmd
end
# Generate results and print them. (see ERB#result)
def run(b=TOPLEVEL_BINDING)
print self.result(b)
end
#
# Executes the generated ERB code to produce a completed template, returning
# the results of that code. (See ERB#new for details on how this process can
# be affected by _safe_level_.)
#
# _b_ accepts a Binding or Proc object which is used to set the context of
# code evaluation.
#
def result(b=TOPLEVEL_BINDING)
if @safe_level
th = Thread.start {
$SAFE = @safe_level
eval(@src, b, (@filename || '(erb)'), 1)
}
return th.value
else
return eval(@src, b, (@filename || '(erb)'), 1)
end
end
def def_method(mod, methodname, fname='(ERB)') # :nodoc:
mod.module_eval("def #{methodname}\n" + self.src + "\nend\n", fname, 0)
end
def def_module(methodname='erb') # :nodoc:
mod = Module.new
def_method(mod, methodname)
mod
end
def def_class(superklass=Object, methodname='result') # :nodoc:
cls = Class.new(superklass)
def_method(cls, methodname)
cls
end
end
#--
# ERB::Util
class ERB
# A utility module for conversion routines, often handy in HTML generation.
module Util
public
#
# A utility method for escaping HTML tag characters in _s_.
#
# require "erb"
# include ERB::Util
#
# puts html_escape("is a > 0 & a < 10?")
#
# _Generates_
#
# is a > 0 & a < 10?
#
def html_escape(s)
s.to_s.gsub(/&/, "&").gsub(/\"/, """).gsub(/>/, ">").gsub(/</, "<")
end
alias h html_escape
#
# A utility method for encoding the String _s_ as a URL.
#
# require "erb"
# include ERB::Util
#
# puts url_encode("Programming Ruby: The Pragmatic Programmer's Guide")
#
# _Generates_
#
# Programming%20Ruby%3A%20%20The%20Pragmatic%20Programmer%27s%20Guide
#
def url_encode(s)
s.to_s.gsub(/[^a-zA-Z0-9_\-.]/n){ sprintf("%%%02X", $&.unpack("C")[0]) }
end
alias u url_encode
end
end
#--
# ERB::DefMethod
class ERB
module DefMethod # :nodoc:
public
def def_erb_method(methodname, erb)
if erb.kind_of? String
fname = erb
File.open(fname) {|f| erb = ERB.new(f.read) }
erb.def_method(self, methodname, fname)
else
erb.def_method(self, methodname)
end
end
module_function :def_erb_method
end
end