Smarty 3.1.8 in the registration function Registerplugin use related issues

Smarty 3.1.8 in the registration function Registerplugin use problem
Have encountered such a problem in learning Smarty
In the php file I wrote this

PHP Code

  
   Function Demo ($params) {extract ($params);    echo $a. $b; } $tpl->registerplugin (' Block ', ' demo ', ' demo ');

Then write this in the template file:

HTML Code

  
   <{demo a=1 b=text}> <{/demo}>

How to Output two x 1text 1text


To solve!

------Solution--------------------
discuss

The problem is still unresolved.

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