Class: Mustache::JavascriptGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/mustache/javascript_generator.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ JavascriptGenerator

Returns a new instance of JavascriptGenerator.



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# File 'lib/mustache/javascript_generator.rb', line 5

def initialize
  @n        = 0
  @globals  = []
  @locals   = []
  @helpers  = {}
  @partials = {}
end

Instance Method Details

#compile(exp) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 139

def compile(exp)
  main = global
  body = global

  compile_closure!(body, exp)

  helpers = self.helpers

  <<-JS.gsub("        ", "")
    (function() {
      #{globals.strip}
      #{helpers.strip}
      #{partials.strip}

      #{main} = function #{main}(obj) {
        var stack, out;
        stack = [];
        stack.push(obj);
        out = [];
        #{body}(stack, out);
        return out.join("");
      };

      return #{main};
    })()
  JS
end

#compile!(exp) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 167

def compile!(exp)
  case exp.first
  when :multi
    exp[1..-1].map { |e| compile!(e) }.join
  when :static
    str(exp[1])
  when :mustache
    send("on_#{exp[1]}", *exp[2..-1])
  else
    raise "Unhandled exp: #{exp.first}"
  end
end

#compile_closure!(name, tokens) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 242

def compile_closure!(name, tokens)
  @locals.push([])
  code = compile!(tokens)
  locals = self.locals
  @locals.pop

  @partials[name] = <<-JS
    #{name} = function #{name}(stack, out) {
      #{locals.strip}
      #{code.strip}
    };
  JS

  nil
end

#global(name = nil) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 313

def global(name = nil)
  if name
    @globals << name.to_sym
    name
  else
    @n += 1
    name = :"g#{@n}"
    @globals << name
    name
  end
end

#globals ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 119

def globals
  if @globals.any?
    "var #{@globals.join(', ')};\n"
  else
    ""
  end
end

#helpers ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 13

def helpers
  out = ""

  if @helpers[:fetch]
    global :fetch
    out << <<-JS
      fetch = function fetch(stack, key) {
        var i, v;
        for (i = stack.length - 1; i >= 0; i -= 1) {
          v = stack[i][key];
          if (v) {
            return v;
          }
        }
      };
    JS
  end

  if @helpers[:escape]
    global :escape
    out << <<-JS
      escape = function escape(value) {
        return ('' + value)
          .replace(/&/g, '&amp;')
          .replace(/</g, '&lt;')
          .replace(/>/g, '&gt;')
          .replace(/\x22/g, '&quot;');
      };
    JS
  end

  if @helpers[:isEmpty]
    @helpers[:isArray] = @helpers[:isObject] = true
    global :isEmpty
    out << <<-JS
      isEmpty = function isEmpty(obj) {
        var key;

        if (!obj) {
          return true;
        } else if (isArray(obj)) {
          return obj.length === 0;
        } else if (isObject(obj)) {
          for (key in obj) {
            if (obj.hasOwnProperty(key)) {
              return false;
            }
          }
          return true;
        } else {
          return false;
        }
      };
    JS
  end

  if @helpers[:isArray]
    global :isArray
    out << <<-JS
      isArray = Array.isArray || function (obj) {
        return Object.prototype.toString.call(obj) === '[object Array]';
      };
    JS
  end

  if @helpers[:isObject]
    global :isObject
    out << <<-JS
      isObject = function isObject(obj) {
        return (obj && typeof obj === 'object');
      };
    JS
  end

  if @helpers[:isFunction]
    global :isFunction
    out << <<-JS
      isFunction = function isFunction(obj) {
        return !!(obj && obj.constructor && obj.call && obj.apply);
      };
    JS
  end

  if @helpers[:reduce]
    global :reduce
    out << <<-JS
      reduce = Array.prototype.reduce || function (iterator, memo) {
        var i;
        for (i = 0; i < this.length; i++) {
          memo = iterator(memo, this[i]);
        }
        return memo;
      };
    JS

    global :traverse
    out << <<-JS
      traverse = function traverse(value, key) {
        return value && value[key];
      };
    JS
  end

  out.gsub("          ", "")
end

#local(name = nil) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 325

def local(name = nil)
  raise "not in closure" unless @locals.last
  @locals.last << name.to_sym
  name
end

#locals ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 127

def locals
  if @locals.last.any?
    "var #{@locals.last.join(', ')};\n"
  else
    ""
  end
end

#on_etag(name) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 275

def on_etag(name)
  @helpers[:isFunction] = true
  @helpers[:isEmpty] = @helpers[:escape] = true

  v = local(:v)

  <<-JS
    #{v} = #{compile!(name).strip};
    if (isFunction(#{v})) {
      #{v} = #{v}.call(stack[stack.length - 1]);
    }
    if (!isEmpty(#{v})) {
      out.push(escape(#{v}));
    }
  JS
end

#on_fetch(names) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 292

def on_fetch(names)
  @helpers[:fetch] = true

  names = names.map { |n| n.to_s }

  case names.length
  when 0
    "stack[stack.length-1]"
  when 1
    "fetch(stack, #{names.first.inspect})"
  else
    @helpers[:reduce] = true
    initial, *rest = names
    "reduce.call(#{rest.inspect}, traverse, fetch(stack, #{initial.inspect}))"
  end
end

#on_inverted_section(name, content, raw, _) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 214

def on_inverted_section(name, content, raw, _)
  @helpers[:isEmpty] = true

  f, v = global, local(:v)

  compile_closure!(f, content)

  <<-JS
    #{v} = #{compile!(name).strip};
    if (isEmpty(#{v})) {
      #{f}(stack, out);
    }
  JS
end

#on_partial(name, indentation) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 229

def on_partial(name, indentation)
  unless @partials[name]
    @partials[name] = true # Stub for recursion

    source   = Mustache.partial(name).to_s.gsub(/^/, indentation)
    template = Mustache.templateify(source)

    compile_closure!(name, template.tokens)
  end

  "#{name}(stack, out);\n"
end

#on_section(name, content, raw, delims) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 180

def on_section(name, content, raw, delims)
  @helpers[:isEmpty] = true
  @helpers[:isObject] = @helpers[:isArray] = @helpers[:isFunction] = true

  f, v, i = global, local(:v), local(:i)

  compile_closure!(f, content)

  <<-JS
    #{v} = #{compile!(name).strip};
    if (!isEmpty(#{v})) {
      if (isFunction(#{v})) {
        out.push(#{v}.call(stack[stack.length - 1], function () {
          var out = [];
          #{f}(stack, out);
          return out.join("");
        }));
      } else if (isArray(#{v})) {
        for (#{i} = 0; #{i} < #{v}.length; #{i} += 1) {
          stack.push(#{v}[#{i}]);
          #{f}(stack, out);
          stack.pop();
        }
      } else if (isObject(#{v})) {
        stack.push(#{v});
        #{f}(stack, out);
        stack.pop();
      } else {
        #{f}(stack, out);
      }
    }
  JS
end

#on_utag(name) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 258

def on_utag(name)
  @helpers[:isFunction] = true
  @helpers[:isEmpty] = true

  v = local(:v)

  <<-JS
    #{v} = #{compile!(name).strip};
    if (isFunction(#{v})) {
      #{v} = #{v}.call(stack[stack.length - 1]);
    }
    if (!isEmpty(#{v})) {
      out.push(#{v});
    }
  JS
end

#partials ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 135

def partials
  @partials.values.join("\n")
end

#str(s) ⇒ Object 



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# File 'lib/mustache/javascript_generator.rb', line 309

def str(s)
  "out.push(#{s.inspect});\n"
end