Class | Haml::Engine |
In: |
lib/haml/engine.rb
|
Parent: | Object |
This is the frontend for using Haml programmatically. It can be directly used by the user by creating a new instance and calling \{render} to render the template. For example:
template = File.read('templates/really_cool_template.haml') haml_engine = Haml::Engine.new(template) output = haml_engine.render puts output
Precompiles the Haml template.
@param template [String] The Haml template @param options [{Symbol => Object}] An options hash;
see {file:HAML_REFERENCE.md#haml_options the Haml options documentation}
@raise [Haml::Error] if there‘s a Haml syntax error in the template
# File lib/haml/engine.rb, line 72 72: def initialize(template, options = {}) 73: @options = { 74: :suppress_eval => false, 75: :attr_wrapper => "'", 76: 77: # Don't forget to update the docs in doc-src/HAML_REFERENCE.md 78: # if you update these 79: :autoclose => %w[meta img link br hr input area param col base], 80: :preserve => %w[textarea pre code], 81: 82: :filename => '(haml)', 83: :line => 1, 84: :ugly => false, 85: :format => :xhtml, 86: :escape_html => false, 87: } 88: 89: 90: template = check_haml_encoding(template) do |msg, line| 91: raise Haml::Error.new(msg, line) 92: end 93: 94: unless ruby1_8? 95: @options[:encoding] = Encoding.default_internal || template.encoding 96: @options[:encoding] = "utf-8" if @options[:encoding].name == "US-ASCII" 97: end 98: @options.merge! options.reject {|k, v| v.nil?} 99: @index = 0 100: 101: unless [:xhtml, :html4, :html5].include?(@options[:format]) 102: raise Haml::Error, "Invalid output format #{@options[:format].inspect}" 103: end 104: 105: if @options[:encoding] && @options[:encoding].is_a?(Encoding) 106: @options[:encoding] = @options[:encoding].name 107: end 108: 109: # :eod is a special end-of-document marker 110: @template = (template.rstrip).split(/\r\n|\r|\n/) + [:eod, :eod] 111: @template_index = 0 112: @to_close_stack = [] 113: @output_tabs = 0 114: @template_tabs = 0 115: @flat = false 116: @newlines = 0 117: @precompiled = '' 118: @to_merge = [] 119: @tab_change = 0 120: 121: precompile 122: rescue Haml::Error => e 123: if @index || e.line 124: e.backtrace.unshift "#{@options[:filename]}:#{(e.line ? e.line + 1 : @index) + @options[:line] - 1}" 125: end 126: raise 127: end
Defines a method on `object` with the given name that renders the template and returns the result as a string.
If `object` is a class or module, the method will instead by defined as an instance method. For example:
t = Time.now Haml::Engine.new("%p\n Today's date is\n .date= self.to_s").def_method(t, :render) t.render #=> "<p>\n Today's date is\n <div class='date'>Fri Nov 23 18:28:29 -0800 2007</div>\n</p>\n" Haml::Engine.new(".upcased= upcase").def_method(String, :upcased_div) "foobar".upcased_div #=> "<div class='upcased'>FOOBAR</div>\n"
The first argument of the defined method is a hash of local variable names to values. However, due to an unfortunate Ruby quirk, the local variables which can be assigned must be pre-declared. This is done with the `local_names` argument. For example:
# This works obj = Object.new Haml::Engine.new("%p= foo").def_method(obj, :render, :foo) obj.render(:foo => "Hello!") #=> "<p>Hello!</p>" # This doesn't obj = Object.new Haml::Engine.new("%p= foo").def_method(obj, :render) obj.render(:foo => "Hello!") #=> NameError: undefined local variable or method `foo'
Note that Haml modifies the evaluation context (either the scope object or the `self` object of the scope binding). It extends {Haml::Helpers}, and various instance variables are set (all prefixed with `haml_`).
@param object [Object, Module] The object on which to define the method @param name [String, Symbol] The name of the method to define @param local_names [Array<Symbol>] The names of the locals that can be passed to the proc
# File lib/haml/engine.rb, line 272 272: def def_method(object, name, *local_names) 273: method = object.is_a?(Module) ? :module_eval : :instance_eval 274: 275: object.send(method, "def #{name}(_haml_locals = {}); #{precompiled_with_ambles(local_names)}; end", 276: @options[:filename], @options[:line]) 277: end
@return [Boolean] Whether or not the format is HTML4.
# File lib/haml/engine.rb, line 44 44: def html4? 45: @options[:format] == :html4 46: end
@return [Boolean] Whether or not the format is HTML5.
# File lib/haml/engine.rb, line 49 49: def html5? 50: @options[:format] == :html5 51: end
The source code that is evaluated to produce the Haml document.
In Ruby 1.9, this is automatically converted to the correct encoding (see {file:HAML_REFERENCE.md#encoding-option the `:encoding` option}).
@return [String]
# File lib/haml/engine.rb, line 59 59: def precompiled 60: return @precompiled if ruby1_8? 61: encoding = Encoding.find(@options[:encoding]) 62: return @precompiled.force_encoding(encoding) if encoding == Encoding::BINARY 63: return @precompiled.encode(encoding) 64: end
Processes the template and returns the result as a string.
`scope` is the context in which the template is evaluated. If it‘s a `Binding` or `Proc` object, Haml uses it as the second argument to `Kernel#eval`; otherwise, Haml just uses its `instance_eval` context.
Note that Haml modifies the evaluation context (either the scope object or the `self` object of the scope binding). It extends {Haml::Helpers}, and various instance variables are set (all prefixed with `haml_`). For example:
s = "foobar" Haml::Engine.new("%p= upcase").render(s) #=> "<p>FOOBAR</p>" # s now extends Haml::Helpers s.respond_to?(:html_attrs) #=> true
`locals` is a hash of local variables to make available to the template. For example:
Haml::Engine.new("%p= foo").render(Object.new, :foo => "Hello, world!") #=> "<p>Hello, world!</p>"
If a block is passed to render, that block is run when `yield` is called within the template.
Due to some Ruby quirks, if `scope` is a `Binding` or `Proc` object and a block is given, the evaluation context may not be quite what the user expects. In particular, it‘s equivalent to passing `eval("self", scope)` as `scope`. This won‘t have an effect in most cases, but if you‘re relying on local variables defined in the context of `scope`, they won‘t work.
@param scope [Binding, Proc, Object] The context in which the template is evaluated @param locals [{Symbol => Object}] Local variables that will be made available
to the template
@param block [to_proc] A block that can be yielded to within the template @return [String] The rendered template
# File lib/haml/engine.rb, line 170 170: def render(scope = Object.new, locals = {}, &block) 171: buffer = Haml::Buffer.new(scope.instance_variable_get('@haml_buffer'), options_for_buffer) 172: 173: if scope.is_a?(Binding) || scope.is_a?(Proc) 174: scope_object = eval("self", scope) 175: scope = scope_object.instance_eval{binding} if block_given? 176: else 177: scope_object = scope 178: scope = scope_object.instance_eval{binding} 179: end 180: 181: set_locals(locals.merge(:_hamlout => buffer, :_erbout => buffer.buffer), scope, scope_object) 182: 183: scope_object.instance_eval do 184: extend Haml::Helpers 185: @haml_buffer = buffer 186: end 187: 188: eval(precompiled + ";" + precompiled_method_return_value, 189: scope, @options[:filename], @options[:line]) 190: ensure 191: # Get rid of the current buffer 192: scope_object.instance_eval do 193: @haml_buffer = buffer.upper 194: end 195: end
Returns a proc that, when called, renders the template and returns the result as a string.
`scope` works the same as it does for render.
The first argument of the returned proc is a hash of local variable names to values. However, due to an unfortunate Ruby quirk, the local variables which can be assigned must be pre-declared. This is done with the `local_names` argument. For example:
# This works Haml::Engine.new("%p= foo").render_proc(Object.new, :foo).call :foo => "Hello!" #=> "<p>Hello!</p>" # This doesn't Haml::Engine.new("%p= foo").render_proc.call :foo => "Hello!" #=> NameError: undefined local variable or method `foo'
The proc doesn‘t take a block; any yields in the template will fail.
@param scope [Binding, Proc, Object] The context in which the template is evaluated @param local_names [Array<Symbol>] The names of the locals that can be passed to the proc @return [Proc] The proc that will run the template
# File lib/haml/engine.rb, line 222 222: def render_proc(scope = Object.new, *local_names) 223: if scope.is_a?(Binding) || scope.is_a?(Proc) 224: scope_object = eval("self", scope) 225: else 226: scope_object = scope 227: scope = scope_object.instance_eval{binding} 228: end 229: 230: eval("Proc.new { |*_haml_locals| _haml_locals = _haml_locals[0] || {};" + 231: precompiled_with_ambles(local_names) + "}\n", scope, @options[:filename], @options[:line]) 232: end
@return [Boolean] Whether or not the format is XHTML.
# File lib/haml/engine.rb, line 34 34: def xhtml? 35: not html? 36: end
Returns a subset of \{options}: those that {Haml::Buffer} cares about. All of the values here are such that when `inspect` is called on the hash, it can be `Kernel#eval`ed to get the same result back.
See {file:HAML_REFERENCE.md#haml_options the Haml options documentation}.
@return [{Symbol => Object}] The options hash
# File lib/haml/engine.rb, line 288 288: def options_for_buffer 289: { 290: :autoclose => @options[:autoclose], 291: :preserve => @options[:preserve], 292: :attr_wrapper => @options[:attr_wrapper], 293: :ugly => @options[:ugly], 294: :format => @options[:format], 295: :encoding => @options[:encoding], 296: :escape_html => @options[:escape_html], 297: } 298: end