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# -*- coding: us-ascii -*-
# frozen_string_literal: true
# = ERB -- Ruby Templating
#
# Author:: Masatoshi SEKI
# Documentation:: James Edward Gray II, Gavin Sinclair, and Simon Chiang
#
# 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.
require 'cgi/util'
require 'erb/version'
require 'erb/compiler'
require 'erb/def_method'
require 'erb/util'
#
# = 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 %> (`<% #` doesn't work. Don't use Ruby comments.)
# % 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 binding used to resolve local variables in the template.
#
# See the ERB.new and ERB#result methods for more detail.
#
# == Character encodings
#
# ERB (or Ruby code generated by ERB) returns a string in the same
# character encoding as the input string. When the input string has
# a magic comment, however, it returns a string in the encoding specified
# by the magic comment.
#
# # -*- coding: utf-8 -*-
# require 'erb'
#
# template = ERB.new <<EOF
# <%#-*- coding: Big5 -*-%>
# \_\_ENCODING\_\_ is <%= \_\_ENCODING\_\_ %>.
# EOF
# puts template.result
#
# <em>Prints:</em> \_\_ENCODING\_\_ is Big5.
#
#
# == 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, trim_mode: "%<>")
#
# # 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.
# For example, RDoc, distributed with Ruby, uses its own template engine, which
# can be reused elsewhere.
#
# Other popular engines could be found in the corresponding
# {Category}[https://www.ruby-toolbox.com/categories/template_engines] of
# The Ruby Toolbox.
#
class ERB
Revision = '$Date:: $' # :nodoc: #'
deprecate_constant :Revision
# Returns revision information for the erb.rb module.
def self.version
VERSION
end
#
# 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 _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 %>
# - omit blank 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 variables
# ERB.new(<<~'END_PRODUCT', trim_mode: "", eoutvar: "@product").result b
# <%= PRODUCT[:name] %>
# <%= PRODUCT[:desc] %>
# END_PRODUCT
# ERB.new(<<~'END_PRICE', trim_mode: "", eoutvar: "@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=NOT_GIVEN, legacy_trim_mode=NOT_GIVEN, legacy_eoutvar=NOT_GIVEN, trim_mode: nil, eoutvar: '_erbout')
# Complex initializer for $SAFE deprecation at [Feature #14256]. Use keyword arguments to pass trim_mode or eoutvar.
if safe_level != NOT_GIVEN
warn 'Passing safe_level with the 2nd argument of ERB.new is deprecated. Do not use it, and specify other arguments as keyword arguments.', uplevel: 1
end
if legacy_trim_mode != NOT_GIVEN
warn 'Passing trim_mode with the 3rd argument of ERB.new is deprecated. Use keyword argument like ERB.new(str, trim_mode: ...) instead.', uplevel: 1
trim_mode = legacy_trim_mode
end
if legacy_eoutvar != NOT_GIVEN
warn 'Passing eoutvar with the 4th argument of ERB.new is deprecated. Use keyword argument like ERB.new(str, eoutvar: ...) instead.', uplevel: 1
eoutvar = legacy_eoutvar
end
compiler = make_compiler(trim_mode)
set_eoutvar(compiler, eoutvar)
@src, @encoding, @frozen_string = *compiler.compile(str)
@filename = nil
@lineno = 0
@_init = self.class.singleton_class
end
NOT_GIVEN = Object.new
private_constant :NOT_GIVEN
##
# Creates a new compiler for ERB. See ERB::Compiler.new for details
def make_compiler(trim_mode)
ERB::Compiler.new(trim_mode)
end
# The Ruby code generated by ERB
attr_reader :src
# The encoding to eval
attr_reader :encoding
# The optional _filename_ argument passed to Kernel#eval when the ERB code
# is run
attr_accessor :filename
# The optional _lineno_ argument passed to Kernel#eval when the ERB code
# is run
attr_accessor :lineno
#
# Sets optional filename and line number that will be used in ERB code
# evaluation and error reporting. See also #filename= and #lineno=
#
# erb = ERB.new('<%= some_x %>')
# erb.render
# # undefined local variable or method `some_x'
# # from (erb):1
#
# erb.location = ['file.erb', 3]
# # All subsequent error reporting would use new location
# erb.render
# # undefined local variable or method `some_x'
# # from file.erb:4
#
def location=((filename, lineno))
@filename = filename
@lineno = lineno if lineno
end
#
# 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}.<<"
compiler.insert_cmd = "#{eoutvar}.<<"
compiler.pre_cmd = ["#{eoutvar} = +''"]
compiler.post_cmd = [eoutvar]
end
# Generate results and print them. (see ERB#result)
def run(b=new_toplevel)
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 object which is used to set the context of
# code evaluation.
#
def result(b=new_toplevel)
unless @_init.equal?(self.class.singleton_class)
raise ArgumentError, "not initialized"
end
eval(@src, b, (@filename || '(erb)'), @lineno)
end
# Render a template on a new toplevel binding with local variables specified
# by a Hash object.
def result_with_hash(hash)
b = new_toplevel(hash.keys)
hash.each_pair do |key, value|
b.local_variable_set(key, value)
end
result(b)
end
##
# Returns a new binding each time *near* TOPLEVEL_BINDING for runs that do
# not specify a binding.
def new_toplevel(vars = nil)
b = TOPLEVEL_BINDING
if vars
vars = vars.select {|v| b.local_variable_defined?(v)}
unless vars.empty?
return b.eval("tap {|;#{vars.join(',')}| break binding}")
end
end
b.dup
end
private :new_toplevel
# Define _methodname_ as instance method of _mod_ from compiled Ruby source.
#
# example:
# filename = 'example.rhtml' # 'arg1' and 'arg2' are used in example.rhtml
# erb = ERB.new(File.read(filename))
# erb.def_method(MyClass, 'render(arg1, arg2)', filename)
# print MyClass.new.render('foo', 123)
def def_method(mod, methodname, fname='(ERB)')
src = self.src.sub(/^(?!#|$)/) {"def #{methodname}\n"} << "\nend\n"
mod.module_eval do
eval(src, binding, fname, -1)
end
end
# Create unnamed module, define _methodname_ as instance method of it, and return it.
#
# example:
# filename = 'example.rhtml' # 'arg1' and 'arg2' are used in example.rhtml
# erb = ERB.new(File.read(filename))
# erb.filename = filename
# MyModule = erb.def_module('render(arg1, arg2)')
# class MyClass
# include MyModule
# end
def def_module(methodname='erb')
mod = Module.new
def_method(mod, methodname, @filename || '(ERB)')
mod
end
# Define unnamed class which has _methodname_ as instance method, and return it.
#
# example:
# class MyClass_
# def initialize(arg1, arg2)
# @arg1 = arg1; @arg2 = arg2
# end
# end
# filename = 'example.rhtml' # @arg1 and @arg2 are used in example.rhtml
# erb = ERB.new(File.read(filename))
# erb.filename = filename
# MyClass = erb.def_class(MyClass_, 'render()')
# print MyClass.new('foo', 123).render()
def def_class(superklass=Object, methodname='result')
cls = Class.new(superklass)
def_method(cls, methodname, @filename || '(ERB)')
cls
end
end
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