[Wikitech-l] MW Function for parsing and modifying template arguments on a page

I'm working on a server-side script that will periodically revise wiki pages that all use the same template. Is there a function I can use that will parse a page and then find and replace template arguments with values I determine within my script?

For example, let's say I have Template:Beer like the following:

{{Beer |Name= |Brewery= |Style= |ABV= |IBU= }}

So if I had a page Rocket Fuel:

{{Beer |Name=Rocket Fuel |Brewery=8th Wonder |Style=Vietnamese Coffee Porter |ABV=4.6 |IBU=18 }}

Let's say my script "discovered" an error in one of the arguments and needed to update the page. For example, let's say the IBU was actually 28. Is there a function that will find and replace the value for IBU in the page?

I'm currently using regex, but I'm wondering if there's a more trustworthy method.

Thanks,

Daren