Let $f:X\to Y$ be a function and let $x\in X$. For the image of $x$ under $f$, a popular notation is $f(x)$; while some author prefers $(x)f$. To me, $(x)f$ is far more natural as if we apply a function $f$, then $g$, the result is naturally $f\circ g$ since $$((x)f)g=(x)(f\circ g).$$ But if we use the "usual" one, $f\circ g$ means applying $g$ first, followed by $f$; the order is "reversed".
My question is: Is the notation $(x)f$ outdated, or perhaps "dead"? If one write a research paper/thesis, is it still considered acceptable if s/he uses the notation $(x)f$ instead of $f(x)$?
By the way, under this notation many well known functions will look a bit weird; for example, are you comfortable with $\pi\sin=0$?