Python/ceval.c (part 55)

Source:

cpython 3.14 @ ab2d84fe1023/Python/ceval.c ↗

This annotation covers intrinsic calls and f-string compilation. See python_ceval54_detail for STORE_ATTR specializations.

Map

Lines	Symbol	Role
1-80	CALL_INTRINSIC_1	Single-arg intrinsic: print_expr, import_star, etc.
81-160	CALL_INTRINSIC_2	Two-arg intrinsic: prep_reraise_star, typevar_with_bound
161-240	FORMAT_VALUE	Apply !r/!s/!a and format spec to f-string part
241-320	BUILD_STRING	Concatenate N top-of-stack strings
321-500	FORMAT_SIMPLE / CONVERT_VALUE	Fast path for simple f-string fields

Reading

CALL_INTRINSIC_1

// CPython: Python/ceval.c:5380 CALL_INTRINSIC_1
inst(CALL_INTRINSIC_1, (value -- res)) {
    assert(oparg <= MAX_INTRINSIC_1);
    res = _PyIntrinsics_UnaryFunctions[oparg](tstate, value);
    ERROR_IF(res == NULL, error);
    DECREF_INPUTS();
    DISPATCH();
}

Intrinsics are internal C functions exposed as opcodes for operations that don't fit the standard slot system: print_expr (interactive mode), import_star (from m import *), stopiteration_error (extracting StopIteration.value).

FORMAT_VALUE

// CPython: Python/ceval.c:5460 FORMAT_VALUE
inst(FORMAT_VALUE, (value, fmt_spec if (oparg & FVS_MASK) -- res)) {
    int which_conversion = oparg & FVC_MASK;
    /* Apply conversion: !r, !s, !a */
    if (which_conversion == FVC_REPR)  value = PyObject_Repr(value);
    else if (which_conversion == FVC_STR)   value = PyObject_Str(value);
    else if (which_conversion == FVC_ASCII) value = PyObject_ASCII(value);
    /* Apply format spec */
    if (oparg & FVS_HAVE_SPEC) {
        res = PyObject_Format(value, fmt_spec);
    } else {
        res = PyObject_Format(value, NULL);  /* default __format__ */
    }
    DECREF_INPUTS();
    ERROR_IF(res == NULL, error);
    DISPATCH();
}

f'{x!r:.10}' compiles to LOAD x, FORMAT_VALUE (FVC_REPR | FVS_HAVE_SPEC) with the spec string '.10' below x. The result is a formatted string fragment.

BUILD_STRING

// CPython: Python/ceval.c:5520 BUILD_STRING
inst(BUILD_STRING, (pieces[oparg] -- str)) {
    str = _PyUnicode_JoinArray(&_Py_STR(empty), pieces, oparg);
    DECREF_INPUTS();
    ERROR_IF(str == NULL, error);
    DISPATCH();
}

f'hello {name}!' compiles to LOAD_CONST 'hello ', LOAD name, FORMAT_VALUE, LOAD_CONST '!', BUILD_STRING 3. _PyUnicode_JoinArray joins oparg pieces with an empty separator in one allocation.

gopy notes

CALL_INTRINSIC_1 is in vm/eval_simple.go, dispatching on oparg to a table of Go functions in vm/intrinsics.go. FORMAT_VALUE calls objects.Repr, objects.Str, or objects.ASCII for the conversion, then objects.Format. BUILD_STRING calls objects.UnicodeJoinSlice.