I am simply interested in ways to write $$ x \mapsto \min(b, \max(a, x)) $$ in a more intuitive way for some $a<b \in \mathbb{R}$.
Something like $x \mid_a^b$ but not something I invented just now.
Best one so far: $ a \lor x \land b $ thanks to HallaSurvivor.
Some people write $a \wedge b$ for the min function, and $a \vee b$ for the max. Then the function you want would be written
$$x \mapsto a \vee x \wedge b$$
Or, even more succinctly
$$a \vee - \wedge b$$
I hope this helps! ^_^