Parent

Tilt::Template

Base class for template implementations. Subclasses must implement the prepare method and one of the evaluate or precompiled_template methods.

Attributes

default_mime_type[RW]
engine_initialized[RW]
engine_initialized?[RW]
data[R]

Template source; loaded from a file or given directly.

file[R]

The name of the file where the template data was loaded from.

line[R]

The line number in file where template data was loaded from.

options[R]

A Hash of template engine specific options. This is passed directly to the underlying engine and is not used by the generic template interface.

Public Class Methods

new(file=nil, line=1, options={}, &block) click to toggle source

Create a new template with the file, line, and options specified. By default, template data is read from the file. When a block is given, it should read template data and return as a String. When file is nil, a block is required.

All arguments are optional.

# File lib/tilt/template.rb, line 38
def initialize(file=nil, line=1, options={}, &block)
  @file, @line, @options = nil, 1, {}

  [options, line, file].compact.each do |arg|
    case
    when arg.respond_to?(:to_str)  ; @file = arg.to_str
    when arg.respond_to?(:to_int)  ; @line = arg.to_int
    when arg.respond_to?(:to_hash) ; @options = arg.to_hash.dup
    else raise TypeError
    end
  end

  raise ArgumentError, "file or block required" if (@file || block).nil?

  # call the initialize_engine method if this is the very first time
  # an instance of this class has been created.
  if !self.class.engine_initialized?
    initialize_engine
    self.class.engine_initialized = true
  end

  # used to hold compiled template methods
  @compiled_method = {}

  # used on 1.9 to set the encoding if it is not set elsewhere (like a magic comment)
  # currently only used if template compiles to ruby
  @default_encoding = @options.delete :default_encoding

  # load template data and prepare (uses binread to avoid encoding issues)
  @reader = block || lambda { |t| File.respond_to?(:binread) ? File.binread(@file) : File.read(@file) }
  @data = @reader.call(self)
  prepare
end

Protected Class Methods

cached_evaluate(scope, locals, &block) click to toggle source

Redefine itself to use method compilation the next time:

# File lib/tilt/template.rb, line 138
def self.cached_evaluate(scope, locals, &block)
  method = compiled_method(locals.keys)
  method.bind(scope).call(locals, &block)
end

Public Instance Methods

basename(suffix='') click to toggle source

The basename of the template file.

# File lib/tilt/template.rb, line 80
def basename(suffix='')
  File.basename(file, suffix) if file
end
eval_file() click to toggle source

The filename used in backtraces to describe the template.

# File lib/tilt/template.rb, line 90
def eval_file
  file || '(__TEMPLATE__)'
end
name() click to toggle source

The template file's basename with all extensions chomped off.

# File lib/tilt/template.rb, line 85
def name
  basename.split('.', 2).first if basename
end
render(scope=Object.new, locals={}, &block) click to toggle source

Render the template in the given scope with the locals specified. If a block is given, it is typically available within the template via yield.

# File lib/tilt/template.rb, line 75
def render(scope=Object.new, locals={}, &block)
  evaluate scope, locals || {}, &block
end

Protected Instance Methods

cached_evaluate(scope, locals, &block) click to toggle source

Process the template and return the result. The first time this method is called, the template source is evaluated with instance_eval. On the sequential method calls it will compile the template to an unbound method which will lead to better performance. In any case, template executation is guaranteed to be performed in the scope object with the locals specified and with support for yielding to the block.

# File lib/tilt/template.rb, line 136
def cached_evaluate(scope, locals, &block)
  # Redefine itself to use method compilation the next time:
  def self.cached_evaluate(scope, locals, &block)
    method = compiled_method(locals.keys)
    method.bind(scope).call(locals, &block)
  end

  # Use instance_eval the first time:
  evaluate_source(scope, locals, &block)
end
compiled_method(locals_keys) click to toggle source

The compiled method for the locals keys provided.

# File lib/tilt/template.rb, line 200
def compiled_method(locals_keys)
  @compiled_method[locals_keys] ||=
    compile_template_method(locals_keys)
end
evaluate(scope, locals, &block) click to toggle source
# File lib/tilt/template.rb, line 126
def evaluate(scope, locals, &block)
  cached_evaluate(scope, locals, &block)
end
initialize_engine() click to toggle source

Called once and only once for each template subclass the first time the template class is initialized. This should be used to require the underlying template library and perform any initial setup.

# File lib/tilt/template.rb, line 98
def initialize_engine
end
precompiled(locals) click to toggle source

Generates all template source by combining the preamble, template, and postamble and returns a two-tuple of the form: [source, offset], where source is the string containing (Ruby) source code for the template and offset is the integer line offset where line reporting should begin.

Template subclasses may override this method when they need complete control over source generation or want to adjust the default line offset. In most cases, overriding the precompiled_template method is easier and more appropriate.

# File lib/tilt/template.rb, line 156
def precompiled(locals)
  preamble = precompiled_preamble(locals)
  template = precompiled_template(locals)
  magic_comment = extract_magic_comment(template)
  if magic_comment
    # Magic comment e.g. "# coding: utf-8" has to be in the first line.
    # So we copy the magic comment to the first line.
    preamble = magic_comment + "\n" + preamble
  end
  parts = [
    preamble,
    template,
    precompiled_postamble(locals)
  ]
  [parts.join("\n"), preamble.count("\n") + 1]
end
precompiled_postamble(locals) click to toggle source

Generates postamble code for the precompiled template source. The string returned from this method is appended to the precompiled template source.

# File lib/tilt/template.rb, line 195
def precompiled_postamble(locals)
  ''
end
precompiled_preamble(locals) click to toggle source

Generates preamble code for initializing template state, and performing locals assignment. The default implementation performs locals assignment only. Lines included in the preamble are subtracted from the source line offset, so adding code to the preamble does not effect line reporting in Kernel::caller and backtraces.

# File lib/tilt/template.rb, line 188
def precompiled_preamble(locals)
  locals.map { |k,v| "#{k} = locals[#{k.inspect}]" }.join("\n")
end
precompiled_template(locals) click to toggle source

A string containing the (Ruby) source code for the template. The default Template#evaluate implementation requires either this method or the precompiled method be overridden. When defined, the base Template guarantees correct file/line handling, locals support, custom scopes, and support for template compilation when the scope object allows it.

# File lib/tilt/template.rb, line 179
def precompiled_template(locals)
  raise NotImplementedError
end
prepare() click to toggle source

Do whatever preparation is necessary to setup the underlying template engine. Called immediately after template data is loaded. Instance variables set in this method are available when evaluate is called.

Subclasses must provide an implementation of this method.

# File lib/tilt/template.rb, line 116
def prepare
  if respond_to?(:compile!)
    # backward compat with tilt < 0.6; just in case
    warn 'Tilt::Template#compile! is deprecated; implement #prepare instead.'
    compile!
  else
    raise NotImplementedError
  end
end
require_template_library(name) click to toggle source

Like Kernel::require but issues a warning urging a manual require when running under a threaded environment.

# File lib/tilt/template.rb, line 103
def require_template_library(name)
  if Thread.list.size > 1
    warn "WARN: tilt autoloading '#{name}' in a non thread-safe way; " +
         "explicit require '#{name}' suggested."
  end
  require name
end

[Validate]

Generated with the Darkfish Rdoc Generator 2.