Re: Question about adding !function_identifier

> > The tricky part is that PHP is a highly dynamic language, so there's a lot > of cases where the analysis can only return "maybe". My understanding is > that this is what a lot of the work on Hack is doing: creating a language > which looks a lot like PHP, but doesn't have as many ambiguous cases which > can't be analysed statically. > Quite a lot of code that apparently cannot be statically analysed could be if the static analyser was programmable. To give a simple example: $result = mysqli_query ($conn, 'select * from some_table'); $arr = mysqli_fetch_assoc ($result); The contents of '$arr' cannot be known using only the data provided in this code, however it's contents is statically knowable. If a static analyser were programmable, it could parse the SQL query and query the database to find out what keys exist in some_table. Thus it could check for references to non-existing keys. I suspect this is the case for a lot of 'non analysable code', it can only function within a known set of states, but the type system is unaware of those states.