I try to call a function within a function, but I get an error. Is this not possible or is it a bug?

startscript {
set string <test; $left($lcase("testtest")$; 4)$>
msg <#test#>
}

Not possible in Quest 4 unfortunately, as it gets muddled up trying to find the end of the first function name - that's what the $ symbols are there for.

Quest 5 takes a more traditional approach to expressions, so you can nest function calls within function calls just as in any other programming language. But in Quest 4 you have to work around this, by putting the nested function call inside a variable first.