function grammar

[Linda Walsh]

from man bash, to define a function use;

"function" "name" <compound-command>
 OR
"name" () <compound-command>

right?

And Compound Commands are:

 ( <list>)
  { <list>; )
 (( expression ))
 [[ expression ]]
...et al....

so why do I get a syntax error for

function good_dir [[ -n $1 && -d $1 && -r $1  && -x $1 ]]

bash: syntax error near unexpected token `[['