TonBERRY/micropython
3
0
Fork 0
Code Pull Requests Activity

py/runtime: Allow multiple *args in a function call.

Browse Source 
This is a partial implementation of PEP 448 to allow unpacking multiple
star args in a function or method call.

This is implemented by changing the emitted bytecodes so that both
positional args and star args are stored as positional args.  A bitmap is
added to indicate if an argument at a given position is a positional
argument or a star arg.

In the generated code, this new bitmap takes the place of the old star arg.
It is stored as a small int, so this means only the first N arguments can
be star args where N is the number of bits in a small int.

The runtime is modified to interpret this new bytecode format while still
trying to perform as few memory reallocations as possible.

Signed-off-by: David Lechner <david@pybricks.com>
This commit is contained in:
David Lechner
2020-03-24 23:54:45 -05:00
committed by Damien George
parent 1e99d29f36
commit 783b1a868f
10 changed files with 151 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
py/compile.c
View File

@@ -37,6 +37,7 @@
#include "py/asmbase.h"
#include "py/nativeglue.h"
#include "py/persistentcode.h"
#include "py/smallint.h"
#if MICROPY_ENABLE_COMPILER
@@ -2397,17 +2398,30 @@ STATIC void compile_trailer_paren_helper(compiler_t *comp, mp_parse_node_t pn_ar
int n_positional = n_positional_extra;
uint n_keyword = 0;
uint star_flags = 0;
mp_parse_node_struct_t *star_args_node = NULL;
mp_uint_t star_args = 0;
for (size_t i = 0; i < n_args; i++) {
if (MP_PARSE_NODE_IS_STRUCT(args[i])) {
mp_parse_node_struct_t *pns_arg = (mp_parse_node_struct_t *)args[i];
if (MP_PARSE_NODE_STRUCT_KIND(pns_arg) == PN_arglist_star) {
if (star_flags & MP_EMIT_STAR_FLAG_SINGLE) {
compile_syntax_error(comp, (mp_parse_node_t)pns_arg, MP_ERROR_TEXT("can't have multiple *x"));
if (star_flags & MP_EMIT_STAR_FLAG_DOUBLE) {
compile_syntax_error(comp, (mp_parse_node_t)pns_arg, MP_ERROR_TEXT("* arg after **"));
return;
}
#if MICROPY_DYNAMIC_COMPILER
if (i > mp_dynamic_compiler.small_int_bits)
#else
if (i > MP_SMALL_INT_BITS)
#endif
{
// If there are not enough bits in a small int to fit the flag, then we consider
// it a syntax error. It should be unlikely to have this many args in practice.
compile_syntax_error(comp, (mp_parse_node_t)pns_arg, MP_ERROR_TEXT("too many args"));
return;
}
star_flags |= MP_EMIT_STAR_FLAG_SINGLE;
star_args_node = pns_arg;
star_args |= 1 << i;
compile_node(comp, pns_arg->nodes[0]);
n_positional++;
} else if (MP_PARSE_NODE_STRUCT_KIND(pns_arg) == PN_arglist_dbl_star) {
star_flags |= MP_EMIT_STAR_FLAG_DOUBLE;
// double-star args are stored as kw arg with key of None
@@ -2438,12 +2452,12 @@ STATIC void compile_trailer_paren_helper(compiler_t *comp, mp_parse_node_t pn_ar
}
} else {
normal_argument:
if (star_flags) {
compile_syntax_error(comp, args[i], MP_ERROR_TEXT("non-keyword arg after */**"));
if (star_flags & MP_EMIT_STAR_FLAG_DOUBLE) {
compile_syntax_error(comp, args[i], MP_ERROR_TEXT("positional arg after **"));
return;
}
if (n_keyword > 0) {
compile_syntax_error(comp, args[i], MP_ERROR_TEXT("non-keyword arg after keyword arg"));
compile_syntax_error(comp, args[i], MP_ERROR_TEXT("positional arg after keyword arg"));
return;
}
compile_node(comp, args[i]);
@@ -2451,14 +2465,9 @@ STATIC void compile_trailer_paren_helper(compiler_t *comp, mp_parse_node_t pn_ar
}
}
// compile the star/double-star arguments if we had them
// if we had one but not the other then we load "null" as a place holder
if (star_flags != 0) {
if (star_args_node == NULL) {
EMIT(load_null);
} else {
compile_node(comp, star_args_node->nodes[0]);
}
// one extra object that contains the star_args map
EMIT_ARG(load_const_small_int, star_args);
}
// emit the function/method call