Interestingly, when using mathematics to describe the semantics of programming languages (say, operational structural semantics for an imperative language), the assignment tends to use an arrow, i.e.
S[ x ↦ V ]
indicates that the new state is equal to old state S, but with variable x now bound to value V.
S[ x ↦ V ]
indicates that the new state is equal to old state S, but with variable x now bound to value V.