Class: Handlebar::Template

Inherits:
Object
  • Object
show all
Defined in:
lib/handlebar/template.rb

Defined Under Namespace

Classes: ArgumentError, MissingVariable, ParseError, RecursionError, TemplateHash, VariableTracker

Constant Summary collapse

TOKEN_REGEXP =

Constants ============================================================

/((?:[^\{]|\{[^\{]|\{\{\{)+)|\{\{\s*([\&\%\$\.\:\?\*\/\=])?([^\}]*)\}\}/.freeze
TOKEN_TRIGGER = 
/\{\{/.freeze

Instance Method Summary collapse

Constructor Details

#initialize(content, options = nil) ⇒ Template

Instance Methods =====================================================



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# File 'lib/handlebar/template.rb', line 30

def initialize(content, options = nil)
  if (options)
    if (source = options[:escape])
      case (source.to_sym)
      when :html, :html_escape
        @escape_method = :html_escape
      when :text, nil
        # Default, ignored
      else
        raise ArgumentError, "Unknown escape source #{source}"
      end
    end
  end
  
  @content =
    case (content)
    when IO
      content.read
    else
      content.to_s
    end
end

Instance Method Details

#compile(options) ⇒ Object 



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# File 'lib/handlebar/template.rb', line 124

def compile(options)
  escape_method = options[:escape_method]
  sections = options[:sections]
  templates = options[:templates]
  variables = options[:variables]
  source = options[:source]

  stack = [ [ :base, nil, VariableTracker.new ] ]
  stack_variables = nil
  
  @content.scan(TOKEN_REGEXP).each do |text, tag_type, tag|
    if (text)
      text = text.sub(/\{(\{\{+)/, '\1').sub(/\}(\}\}+)/, '\1')
      
      source and source << "r<<#{text.inspect};"
    else
      tag = tag.strip
      tag = tag.empty? ? nil : tag.to_sym
      
      case (tag_type)
      when ?&
        # HTML escaped
        index = stack[-1][2][tag.inspect]

        source and source << "v&&r<<h.html_escape(v[#{tag.inspect}].to_s);"
        
        variables and variables[tag] = true

      when ?%
        # URI escaped
        index = stack[-1][2][tag.inspect]

        source and source << "v&&r<<h.uri_escape(v.is_a?(Array)?v[#{index}]:v[#{tag.inspect}]);"

        variables and variables[tag] = true
      when ?$
        # JavaScript escaped
        index = stack[-1][2][tag.inspect]

        source and source << "v&&r<<h.js_escape(v.is_a?(Array)?v[#{index}]:v[#{tag.inspect}]);"

        variables and variables[tag] = true
      when ?.
        # CSS escaped
        index = stack[-1][2][tag.inspect]

        source and source << "v&&r<<h.css_escape(v.is_a?(Array)?v[#{index}]:v[#{tag.inspect}]);"

        variables and variables[tag] = true
      when ?:
        # Defines start of a :section
        index = stack[-1][2][tag.inspect]

        stack_variables ||= 's=[];'
        stack << [ :section, tag, VariableTracker.new ]

        source and source << "if(v);s<<v;v=v.is_a?(Array)?v[#{index}]:(v.is_a?(Hash)&&v[#{tag.inspect}]);"
        source and source << "h.iterate(v){|v|;v=h.cast_as_vars(v, s);"
        
        sections and sections[tag] = true
      when ??
        # Defines start of a ?conditional
        
        stack[-1][2][tag.inspect]

        # The stack will inherit the variable assignment locations from the
        # existing stack layer.
        stack << [ :conditional, tag, stack[-1][2] ]
        source and source << "if(v&&v.is_a?(Hash)&&v[#{tag.inspect}]);"

        variables and variables[tag] = true
      when ?*
        source and source << "_t=t&&t[#{tag.inspect}];r<<(_t.respond_to?(:call)?_t.call(v,t):_t.to_s);"
        
        templates and templates[tag] = true
      when ?/
        # Closes out a section or conditional
        closed = stack.pop
        
        case (closed[0])
        when :section
          if (tag and tag != closed[1])
            raise ParseError, "Template contains unexpected {{#{tag}}}, expected {{#{closed[1]}}}"
          end
          
          source and source << "};v=s.pop;end;"
        when :conditional
          source and source << "end;"
        when :base
          raise ParseError, "Unexpected {{#{tag}}}, too many tags closed"
        end
      when ?=
        # Literal insertion
        index = stack[-1][2][tag.inspect]

        source and source << "v&&r<<(v.is_a?(Array)?v[#{index}]:v[#{tag.inspect}]).to_s;"

        variables and variables[tag] = true
      else
        # Contextual insertion
        index = stack[-1][2][tag.inspect]

        subst = "v.is_a?(Array)?v[#{stack[-1][2][tag.inspect]}]:v[#{tag.inspect}]"
        
        if (escape_method)
          source and source << "v&&r<<h.#{escape_method}(#{subst}.to_s);"
        else
          source and source << "v&&r<<(#{subst}).to_s;"
        end

        variables and variables[tag] = true
      end
    end
  end
  
  unless (stack.length == 1)
    case (stack[1][0])
    when :section
      raise ParseError, "Unclosed {{:#{stack[1][1]}}} in template"
    when :conditional
      raise ParseError, "Unclosed {{?#{stack[1][1]}}} in template"
    else
      raise ParseError, "Unclosed {{#{stack[1][1]}}} in template"
    end
  end
  
  if (source)
    source.replace("begin;c=false;h=Handlebar::Support;lambda{|v,t|raise RecursionError if(c);c=true;#{stack_variables}r='';#{source}c=false;r};end")
  end
  
  true
end

#marshal_dump ⇒ Object 



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# File 'lib/handlebar/template.rb', line 267

def marshal_dump
  [ @content, { :escape => @escape_method } ]
end

#marshal_load(dump) ⇒ Object 



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# File 'lib/handlebar/template.rb', line 271

def marshal_load(dump)
  @content, options = dump
  
  @escape_method = options[:escape]
end

#render(variables = nil, templates = nil, parents = nil) ⇒ Object Also known as: call 



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# File 'lib/handlebar/template.rb', line 63

def render(variables = nil, templates = nil, parents = nil)
  variables =
    case (variables)
    when Array
      variables
    when Hash
      Hash[variables.collect { |k, v| [ k.to_sym, v ] }]
    else
      [ variables ]
    end
    
  if (templates)
    # Unless the template options have already been processed, mapping
    # will need to be performed.
    unless (templates.is_a?(TemplateHash))
      templates = TemplateHash[
        templates.collect do |k, v|
          [
            k,
            case (v)
            when Handlebar::Template, Proc, Array
              v
            when TOKEN_TRIGGER
              self.class.new(v, :escape => @escape_method)
            else
              v.to_s
            end
          ]
        end
      ]
    end
  else
    templates = TemplateHash.new
  end
  
  if (parents)
    case (parents)
    when Array
      _parents = parents.dup
      _parent = _parents.shift
      _parent.render(
        variables,
        templates.merge(
          nil => self.to_proc.call(variables, templates)
        ),
        _parents.empty? ? nil : _parents
      )
    when Handlebar::Template, Proc
      parents.render(
        variables,
        templates.merge(
          nil => self.to_proc.call(variables, templates)
        )
      )
    end
  else
    self.to_proc.call(variables, templates)
  end
end

#to_proc ⇒ Object 



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# File 'lib/handlebar/template.rb', line 53

def to_proc
  @_proc ||= begin
    source = ''

    self.compile(:source => source, :escape_method => @escape_method)

    eval(source)
  end
end

#to_yaml(dump) ⇒ Object 



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# File 'lib/handlebar/template.rb', line 257

def to_yaml(dump)
  _proc, @_proc = @_proc, nil
  
  super(dump)
  
  @_proc = _proc
  
  dump
end