generated definition of snippets function is syntactically wrong

Issue Summary

The 'if' clause is missing braces and a semi-colon. Here's the diff:

Well, no it isn't, the filter completely screws it up. Basically, the code that defines the snippet function needs to go from:

if (!functionexist(fname)) function fname (params) { code }

to

if (!functionexist(fname)) { function fname (params) { code }; }

I'm not a PHP programmer, so there may be a better fix. In particular, it seems like
simply adding the semi-colon after the function def should be sufficient, but it didn't seem to work for me.