How to read smtlib2 strings using Z3 C++ api?

Question

I want to create an expr object from a given SMTLIB2 file. I can see a Z3_parse_smtlib_string function in the C examples. Is there a wrapper for that in the expr class?

Answer 1

The Z3 C++ API does not explicitly provide this functionality as part of the expr class. However, the C++ API can be used alongside the C API, i.e., the function Z3_parse_smtlib_string (or ..._file) can be used to achieve this. Note that this function returns a Z3_ast, which must be converted to an expr object to get back to the C++ "world".

A simple example:

#include <z3++.h>

...

context ctx;
Z3_ast a = Z3_parse_smtlib2_file(ctx, "test.smt2", 0, 0, 0, 0, 0, 0);    
expr e(ctx, a);
std::cout << "Result = " << e << std::endl;

Since the Z3_parse_smtlib2_* functions do not perform error checking, no exception will be thrown upon errors. This can be achieved by calls to context::check_error().