What's the meaning of this line of CoffeeScript? -

i reading through journo's source code , stumbled upon line of code:

markdown  = _.template(source.tostring()) variables 

what variables doing here? _.template(source.tostring()) variables valid stntax @ all?

here's function wrapping line of code:

journo.render = (post, source) ->       catcherrors ->         loadlayout         source or= fs.readfilesync postpath post         variables = rendervariables post         markdown  = _.template(source.tostring()) variables         title     = detecttitle markdown         content   = marked.parser marked.lexer markdown         shared.layout _.extend variables, {title, content} 

yes, valid. parenthesis optional (sometimes) in coffeescript when invoking function, taking result of template , invoking arguments. compiles javascript:

_.template(source.tostring())(variables); 

from coffeescript documentation:

you don't need use parentheses invoke function if you're passing arguments. implicit call wraps forward end of line or block expression.