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Issue #24965: Implement PEP 498 "Literal String Interpolation". Documentation is still needed, I'll open an issue for that.

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Eric V. Smith 2015-09-19 14:51:32 -04:00
parent aed8830af3
commit 235a6f0984
9 changed files with 1965 additions and 63 deletions
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117
Python/compile.c
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@ -731,6 +731,7 @@ compiler_set_qualname(struct compiler *c)
return 1;
}
/* Allocate a new block and return a pointer to it.
Returns NULL on error.
*/
@ -3209,6 +3210,117 @@ compiler_call(struct compiler *c, expr_ty e)
e->v.Call.keywords);
}
static int
compiler_joined_str(struct compiler *c, expr_ty e)
{
/* Concatenate parts of a string using ''.join(parts). There are
probably better ways of doing this.
This is used for constructs like "'x=' f'{42}'", which have to
be evaluated at compile time. */
static PyObject *empty_string;
static PyObject *join_string;
if (!empty_string) {
empty_string = PyUnicode_FromString("");
if (!empty_string)
return 0;
}
if (!join_string) {
join_string = PyUnicode_FromString("join");
if (!join_string)
return 0;
}
ADDOP_O(c, LOAD_CONST, empty_string, consts);
ADDOP_NAME(c, LOAD_ATTR, join_string, names);
VISIT_SEQ(c, expr, e->v.JoinedStr.values);
ADDOP_I(c, BUILD_LIST, asdl_seq_LEN(e->v.JoinedStr.values));
ADDOP_I(c, CALL_FUNCTION, 1);
return 1;
}
/* Note that this code uses the builtin functions format(), str(),
repr(), and ascii(). You can break this code, or make it do odd
things, by redefining those functions. */
static int
compiler_formatted_value(struct compiler *c, expr_ty e)
{
PyObject *conversion_name = NULL;
static PyObject *format_string;
static PyObject *str_string;
static PyObject *repr_string;
static PyObject *ascii_string;
if (!format_string) {
format_string = PyUnicode_InternFromString("format");
if (!format_string)
return 0;
}
if (!str_string) {
str_string = PyUnicode_InternFromString("str");
if (!str_string)
return 0;
}
if (!repr_string) {
repr_string = PyUnicode_InternFromString("repr");
if (!repr_string)
return 0;
}
if (!ascii_string) {
ascii_string = PyUnicode_InternFromString("ascii");
if (!ascii_string)
return 0;
}
ADDOP_NAME(c, LOAD_GLOBAL, format_string, names);
/* If needed, convert via str, repr, or ascii. */
if (e->v.FormattedValue.conversion != -1) {
switch (e->v.FormattedValue.conversion) {
case 's':
conversion_name = str_string;
break;
case 'r':
conversion_name = repr_string;
break;
case 'a':
conversion_name = ascii_string;
break;
default:
PyErr_SetString(PyExc_SystemError,
"Unrecognized conversion character");
return 0;
}
ADDOP_NAME(c, LOAD_GLOBAL, conversion_name, names);
}
/* Evaluate the value. */
VISIT(c, expr, e->v.FormattedValue.value);
/* If needed, convert via str, repr, or ascii. */
if (conversion_name) {
/* Call the function we previously pushed. */
ADDOP_I(c, CALL_FUNCTION, 1);
}
/* If we have a format spec, use format(value, format_spec). Otherwise,
use the single argument form. */
if (e->v.FormattedValue.format_spec) {
VISIT(c, expr, e->v.FormattedValue.format_spec);
ADDOP_I(c, CALL_FUNCTION, 2);
} else {
/* No format spec specified, call format(value). */
ADDOP_I(c, CALL_FUNCTION, 1);
}
return 1;
}
/* shared code between compiler_call and compiler_class */
static int
compiler_call_helper(struct compiler *c,
@ -3878,6 +3990,10 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
case Str_kind:
ADDOP_O(c, LOAD_CONST, e->v.Str.s, consts);
break;
case JoinedStr_kind:
return compiler_joined_str(c, e);
case FormattedValue_kind:
return compiler_formatted_value(c, e);
case Bytes_kind:
ADDOP_O(c, LOAD_CONST, e->v.Bytes.s, consts);
break;
@ -4784,4 +4900,3 @@ PyAST_Compile(mod_ty mod, const char *filename, PyCompilerFlags *flags,
{
return PyAST_CompileEx(mod, filename, flags, -1, arena);
}