text: namespace $ {
  	const err = $mol_view_tree2_error_str
  
  	export function $mol_view_tree2_class_super(
  		this: $mol_ambient_context,
  		klass: $mol_tree2
  	) {
  		if( !class_regex.test( klass.type ) ) return this.$mol_fail(
  			err `Wrong class name at ${klass.span}` 
  		)
  
  		const superclass = klass.kids.length === 1 ? klass.kids[0] : undefined
  
  		if (! superclass) return this.$mol_fail(
  			err`No subclass at ${klass.span}`
  		)
  
  		if( !class_regex.test( superclass.type ) ) return this.$mol_fail(
  			err`Wrong subclass name at ${superclass.span}`
  		)
  
  		return superclass
  	}
  
  	const class_regex = /^\$\w+$/
  }
  