string-to-syntax

string-to-syntax is a built-in function in `C source code'.

(string-to-syntax STRING)

Convert a syntax descriptor STRING into a raw syntax descriptor.
STRING should be a string of the form allowed as argument of
`modify-syntax-entry'. The return value is a raw syntax descriptor: a
cons cell (CODE . MATCHING-CHAR) which can be used, for example, as
the value of a `syntax-table' text property.