This occurs in Scalate 1.4.1. Using { } braces within a string used for an attribute value seems to confuse the scaml parser. For example:

%element{:foo => {"function(){}"}}

The exception is:

org.fusesource.scalate.InvalidSyntaxException: `}' expected but `"' found at 1.32
	at org.fusesource.scalate.scaml.ScamlParser.parse(ScamlParser.scala:375)
	at org.fusesource.scalate.scaml.ScamlCodeGenerator.generate(ScamlCodeGenerator.scala:668)
	at org.fusesource.scalate.TemplateEngine.compileAndLoad(TemplateEngine.scala:684)
	at org.fusesource.scalate.TemplateEngine.compileAndLoadEntry(TemplateEngine.scala:637)
	at org.fusesource.scalate.TemplateEngine.liftedTree1$1(TemplateEngine.scala:368)
	at org.fusesource.scalate.TemplateEngine.load(TemplateEngine.scala:362)
	at org.fusesource.scalate.TemplateEngine.load(TemplateEngine.scala:432)
	at org.fusesource.scalate.RenderContext$$anonfun$render$1$$anonfun$apply$mcV$sp$1.apply(RenderContext.scala:367)
	at org.fusesource.scalate.RenderContext$$anonfun$render$1$$anonfun$apply$mcV$sp$1.apply(RenderContext.scala:367)
	at org.fusesource.scalate.RenderContext$class.withUri(RenderContext.scala:423)
	at org.fusesource.scalate.DefaultRenderContext.withUri(DefaultRenderContext.scala:30)
	at org.fusesource.scalate.RenderContext$$anonfun$render$1.apply(RenderContext.scala:366)
	at org.fusesource.scalate.RenderContext$$anonfun$render$1.apply(RenderContext.scala:366)
	at org.fusesource.scalate.RenderContext$class.withAttributes(RenderContext.scala:397)
	at org.fusesource.scalate.DefaultRenderContext.withAttributes(DefaultRenderContext.scala:30)
	at org.fusesource.scalate.RenderContext$class.render(RenderContext.scala:365)
	at org.fusesource.scalate.DefaultRenderContext.render(DefaultRenderContext.scala:30)

It looks like the use of the braces for expression evaluation is what causes the problem. The following will work fine:

%element{:foo => "function(){}"}

One workaround would be to introduce a variable within the page to store the string value I want, and then use that variable as the attribute's value.