5.2.2 Predicates that operate on strings
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Availability:built-in
Sourceterm_string(?Term, ?String, +Options)
As term_string/2, passing Options to either read_term/2 or write_term/2. For example: 
?- term_string(Term, 'a(A)', [variable_names(VNames)]).
Term = a(_9674),
VNames = ['A'=_9674].