how to loop in templates?

[xploita]

well,the qs is simple

having developed this simple template engine for my own projects,the engine simply replaces the {replacable} tags with the appropriate value.

the template file is read into a string variable $string ,then i use preg_replace_callback to process the tags.

now,i have a problem with the loops.i've though about this:

 

{LOOP_NAME}

things to be {repeated}

{/LOOP}

 

then i though about using preg_replace_callback twice,once to extract the loop body,repeat it then insert it back into $string.

then use the final preg_replace_callback to replace all {replacable} variables.

is this a bad idea for server loads?