From 178395031157f61af5426add2de1d76d91440b21 Mon Sep 17 00:00:00 2001 From: Damien George Date: Tue, 16 Jun 2020 21:42:44 +1000 Subject: [PATCH] py/compile: Implement PEP 572, assignment expressions with := operator. The syntax matches CPython and the semantics are equivalent except that, unlike CPython, MicroPython allows using := to assign to comprehension iteration variables, because disallowing this would take a lot of code to check for it. The new compile-time option MICROPY_PY_ASSIGN_EXPR selects this feature and is enabled by default, following MICROPY_PY_ASYNC_AWAIT. --- py/compile.c | 29 ++++++++++++++++++++++++++++- py/grammar.h | 21 ++++++++++++++++----- py/lexer.c | 6 ++++-- py/lexer.h | 1 + py/mpconfig.h | 5 +++++ tests/cmdline/cmd_parsetree.py.exp | 2 +- 6 files changed, 55 insertions(+), 9 deletions(-) diff --git a/py/compile.c b/py/compile.c index 8835ec2f8d..da5c9190a3 100644 --- a/py/compile.c +++ b/py/compile.c @@ -3,7 +3,7 @@ * * The MIT License (MIT) * - * Copyright (c) 2013-2015 Damien P. George + * Copyright (c) 2013-2020 Damien P. George * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -2108,6 +2108,27 @@ STATIC void compile_lambdef(compiler_t *comp, mp_parse_node_struct_t *pns) { compile_funcdef_lambdef(comp, this_scope, pns->nodes[0], PN_varargslist); } +#if MICROPY_PY_ASSIGN_EXPR +STATIC void compile_namedexpr_helper(compiler_t *comp, mp_parse_node_t pn_name, mp_parse_node_t pn_expr) { + if (!MP_PARSE_NODE_IS_ID(pn_name)) { + compile_syntax_error(comp, (mp_parse_node_t)pn_name, MP_ERROR_TEXT("can't assign to expression")); + } + compile_node(comp, pn_expr); + EMIT(dup_top); + scope_t *old_scope = comp->scope_cur; + if (SCOPE_IS_COMP_LIKE(comp->scope_cur->kind)) { + // Use parent's scope for assigned value so it can "escape" + comp->scope_cur = comp->scope_cur->parent; + } + compile_store_id(comp, MP_PARSE_NODE_LEAF_ARG(pn_name)); + comp->scope_cur = old_scope; +} + +STATIC void compile_namedexpr(compiler_t *comp, mp_parse_node_struct_t *pns) { + compile_namedexpr_helper(comp, pns->nodes[0], pns->nodes[1]); +} +#endif + STATIC void compile_or_and_test(compiler_t *comp, mp_parse_node_struct_t *pns) { bool cond = MP_PARSE_NODE_STRUCT_KIND(pns) == PN_or_test; uint l_end = comp_next_label(comp); @@ -2353,6 +2374,12 @@ STATIC void compile_trailer_paren_helper(compiler_t *comp, mp_parse_node_t pn_ar star_flags |= MP_EMIT_STAR_FLAG_DOUBLE; dblstar_args_node = pns_arg; } else if (MP_PARSE_NODE_STRUCT_KIND(pns_arg) == PN_argument) { + #if MICROPY_PY_ASSIGN_EXPR + if (MP_PARSE_NODE_IS_STRUCT_KIND(pns_arg->nodes[1], PN_argument_4)) { + compile_namedexpr_helper(comp, pns_arg->nodes[0], ((mp_parse_node_struct_t *)pns_arg->nodes[1])->nodes[0]); + n_positional++; + } else + #endif if (!MP_PARSE_NODE_IS_STRUCT_KIND(pns_arg->nodes[1], PN_comp_for)) { if (!MP_PARSE_NODE_IS_ID(pns_arg->nodes[0])) { compile_syntax_error(comp, (mp_parse_node_t)pns_arg, MP_ERROR_TEXT("LHS of keyword arg must be an id")); diff --git a/py/grammar.h b/py/grammar.h index c3d30cdf7c..f5f1ff666d 100644 --- a/py/grammar.h +++ b/py/grammar.h @@ -3,7 +3,7 @@ * * The MIT License (MIT) * - * Copyright (c) 2013-2015 Damien P. George + * Copyright (c) 2013-2020 Damien P. George * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -184,10 +184,10 @@ DEF_RULE_NC(async_stmt_2, or(3), rule(funcdef), rule(with_stmt), rule(for_stmt)) #else DEF_RULE_NC(compound_stmt, or(8), rule(if_stmt), rule(while_stmt), rule(for_stmt), rule(try_stmt), rule(with_stmt), rule(funcdef), rule(classdef), rule(decorated)) #endif -DEF_RULE(if_stmt, c(if_stmt), and(6), tok(KW_IF), rule(test), tok(DEL_COLON), rule(suite), opt_rule(if_stmt_elif_list), opt_rule(else_stmt)) +DEF_RULE(if_stmt, c(if_stmt), and(6), tok(KW_IF), rule(namedexpr_test), tok(DEL_COLON), rule(suite), opt_rule(if_stmt_elif_list), opt_rule(else_stmt)) DEF_RULE_NC(if_stmt_elif_list, one_or_more, rule(if_stmt_elif)) -DEF_RULE_NC(if_stmt_elif, and(4), tok(KW_ELIF), rule(test), tok(DEL_COLON), rule(suite)) -DEF_RULE(while_stmt, c(while_stmt), and(5), tok(KW_WHILE), rule(test), tok(DEL_COLON), rule(suite), opt_rule(else_stmt)) +DEF_RULE_NC(if_stmt_elif, and(4), tok(KW_ELIF), rule(namedexpr_test), tok(DEL_COLON), rule(suite)) +DEF_RULE(while_stmt, c(while_stmt), and(5), tok(KW_WHILE), rule(namedexpr_test), tok(DEL_COLON), rule(suite), opt_rule(else_stmt)) DEF_RULE(for_stmt, c(for_stmt), and(7), tok(KW_FOR), rule(exprlist), tok(KW_IN), rule(testlist), tok(DEL_COLON), rule(suite), opt_rule(else_stmt)) DEF_RULE(try_stmt, c(try_stmt), and(4), tok(KW_TRY), tok(DEL_COLON), rule(suite), rule(try_stmt_2)) DEF_RULE_NC(try_stmt_2, or(2), rule(try_stmt_except_and_more), rule(try_stmt_finally)) @@ -210,6 +210,12 @@ DEF_RULE(suite_block_stmts, c(generic_all_nodes), one_or_more, rule(stmt)) // lambdef: 'lambda' [varargslist] ':' test // lambdef_nocond: 'lambda' [varargslist] ':' test_nocond +#if MICROPY_PY_ASSIGN_EXPR +DEF_RULE(namedexpr_test, c(namedexpr), and_ident(2), rule(test), opt_rule(namedexpr_test_2)) +DEF_RULE_NC(namedexpr_test_2, and_ident(2), tok(OP_ASSIGN), rule(test)) +#else +DEF_RULE_NC(namedexpr_test, or(1), rule(test)) +#endif DEF_RULE_NC(test, or(2), rule(lambdef), rule(test_if_expr)) DEF_RULE(test_if_expr, c(test_if_expr), and_ident(2), rule(or_test), opt_rule(test_if_else)) DEF_RULE_NC(test_if_else, and(4), tok(KW_IF), rule(or_test), tok(KW_ELSE), rule(test)) @@ -276,7 +282,7 @@ DEF_RULE_NC(atom_2b, or(2), rule(yield_expr), rule(testlist_comp)) DEF_RULE(atom_bracket, c(atom_bracket), and(3), tok(DEL_BRACKET_OPEN), opt_rule(testlist_comp), tok(DEL_BRACKET_CLOSE)) DEF_RULE(atom_brace, c(atom_brace), and(3), tok(DEL_BRACE_OPEN), opt_rule(dictorsetmaker), tok(DEL_BRACE_CLOSE)) DEF_RULE_NC(testlist_comp, and_ident(2), rule(testlist_comp_2), opt_rule(testlist_comp_3)) -DEF_RULE_NC(testlist_comp_2, or(2), rule(star_expr), rule(test)) +DEF_RULE_NC(testlist_comp_2, or(2), rule(star_expr), rule(namedexpr_test)) DEF_RULE_NC(testlist_comp_3, or(2), rule(comp_for), rule(testlist_comp_3b)) DEF_RULE_NC(testlist_comp_3b, and_ident(2), tok(DEL_COMMA), opt_rule(testlist_comp_3c)) DEF_RULE_NC(testlist_comp_3c, list_with_end, rule(testlist_comp_2), tok(DEL_COMMA)) @@ -342,7 +348,12 @@ DEF_RULE_NC(arglist_dbl_star, and(2), tok(OP_DBL_STAR), rule(test)) // comp_if: 'if' test_nocond [comp_iter] DEF_RULE_NC(argument, and_ident(2), rule(test), opt_rule(argument_2)) +#if MICROPY_PY_ASSIGN_EXPR +DEF_RULE_NC(argument_2, or(3), rule(comp_for), rule(argument_3), rule(argument_4)) +DEF_RULE_NC(argument_4, and(2), tok(OP_ASSIGN), rule(test)) +#else DEF_RULE_NC(argument_2, or(2), rule(comp_for), rule(argument_3)) +#endif DEF_RULE_NC(argument_3, and_ident(2), tok(DEL_EQUAL), rule(test)) DEF_RULE_NC(comp_iter, or(2), rule(comp_for), rule(comp_if)) DEF_RULE_NC(comp_for, and_blank(5), tok(KW_FOR), rule(exprlist), tok(KW_IN), rule(or_test), opt_rule(comp_iter)) diff --git a/py/lexer.c b/py/lexer.c index 10bb999af6..7d2a251d41 100644 --- a/py/lexer.c +++ b/py/lexer.c @@ -174,7 +174,8 @@ STATIC void indent_pop(mp_lexer_t *lex) { // this means if the start of two ops are the same then they are equal til the last char STATIC const char *const tok_enc = - "()[]{},:;~" // singles + "()[]{},;~" // singles + ":e=" // : := " >= >> >>= "*e=c*e=" // * *= ** **= @@ -194,8 +195,9 @@ STATIC const uint8_t tok_enc_kind[] = { MP_TOKEN_DEL_PAREN_OPEN, MP_TOKEN_DEL_PAREN_CLOSE, MP_TOKEN_DEL_BRACKET_OPEN, MP_TOKEN_DEL_BRACKET_CLOSE, MP_TOKEN_DEL_BRACE_OPEN, MP_TOKEN_DEL_BRACE_CLOSE, - MP_TOKEN_DEL_COMMA, MP_TOKEN_DEL_COLON, MP_TOKEN_DEL_SEMICOLON, MP_TOKEN_OP_TILDE, + MP_TOKEN_DEL_COMMA, MP_TOKEN_DEL_SEMICOLON, MP_TOKEN_OP_TILDE, + MP_TOKEN_DEL_COLON, MP_TOKEN_OP_ASSIGN, MP_TOKEN_OP_LESS, MP_TOKEN_OP_LESS_EQUAL, MP_TOKEN_OP_DBL_LESS, MP_TOKEN_DEL_DBL_LESS_EQUAL, MP_TOKEN_OP_MORE, MP_TOKEN_OP_MORE_EQUAL, MP_TOKEN_OP_DBL_MORE, MP_TOKEN_DEL_DBL_MORE_EQUAL, MP_TOKEN_OP_STAR, MP_TOKEN_DEL_STAR_EQUAL, MP_TOKEN_OP_DBL_STAR, MP_TOKEN_DEL_DBL_STAR_EQUAL, diff --git a/py/lexer.h b/py/lexer.h index b9f97013a1..91767a44bf 100644 --- a/py/lexer.h +++ b/py/lexer.h @@ -96,6 +96,7 @@ typedef enum _mp_token_kind_t { MP_TOKEN_KW_WITH, MP_TOKEN_KW_YIELD, + MP_TOKEN_OP_ASSIGN, MP_TOKEN_OP_TILDE, // Order of these 6 matches corresponding mp_binary_op_t operator diff --git a/py/mpconfig.h b/py/mpconfig.h index 27df3f483a..287b15aaef 100644 --- a/py/mpconfig.h +++ b/py/mpconfig.h @@ -835,6 +835,11 @@ typedef double mp_float_t; #define MICROPY_PY_ASYNC_AWAIT (1) #endif +// Support for assignment expressions with := (see PEP 572, Python 3.8+) +#ifndef MICROPY_PY_ASSIGN_EXPR +#define MICROPY_PY_ASSIGN_EXPR (1) +#endif + // Non-standard .pend_throw() method for generators, allowing for // Future-like behavior with respect to exception handling: an // exception set with .pend_throw() will activate on the next call diff --git a/tests/cmdline/cmd_parsetree.py.exp b/tests/cmdline/cmd_parsetree.py.exp index 18986318a0..42a8228fb7 100644 --- a/tests/cmdline/cmd_parsetree.py.exp +++ b/tests/cmdline/cmd_parsetree.py.exp @@ -3,7 +3,7 @@ tok(4) [ 4] rule(22) (n=4) id(i) -[ 4] rule(44) (n=1) +[ 4] rule(45) (n=1) NULL [ 5] rule(8) (n=0) NULL