Singular Manual: pyobject expressions

| ### 4.28.2 pyobject expressions A pyobject expression is (optional parts in square brackets): an identifier of type pyobject a function returning pyobject pyobject expressions combined by the arithmetic operations `+`, `-`, `*`, `/`, or `^`, and the member-of operators `.` and `::` an list expression with elements made of pyobject expressions (see Type conversion and casting) an string expression (see Type conversion and casting) an int expression (see Type conversion and casting) Example:
      pyobject pystr = "python string ";
    ==> no pyobject support
      pystr;
    ==>    ? missing blackbox_String
    ==>
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 2: `  pystr;`
      pyobject pyint = 2;
      pyint;
    ==>    ? missing blackbox_String
    ==>
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 4: `  pyint;`
      pyobject pylst = list(pystr, pyint);
    ==>    ? missing blackbox_Copy
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 5: `  pyobject pylst = list(pystr, pyint);`
      pylst;
    ==>    ? `pylst` is undefined
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 6: `  pylst;`
      pyint + pyint;
    ==>    ? `pyobject` + `pyobject` failed
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 7: `  pyint + pyint;`
      pyint * pyint;
    ==>    ? `pyobject` * `pyobject` failed
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 8: `  pyint * pyint;`
      pystr + pystr;
    ==>    ? `pyobject` + `pyobject` failed
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 9: `  pystr + pystr;`
      pystr * pyint;
    ==>    ? `pyobject` * `pyobject` failed
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 10: `  pystr * pyint;`
      python_eval("17 + 4");
    ==>    ? `python_eval` is not defined
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 11: `  python_eval("17 + 4");`
      typeof(_);
    ==>    ? missing blackbox_Copy
    ==>    ? error occurred in or before ./examples/pyobject_expressions.sing lin\
       e 12: `  typeof(_);`

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