My first email from yesterday appears messed up - this is attempt 2
The api.value.automove directive doesn't honor an explicit false setting.
-------------------------------------------
// test_automove.y
%skeleton "lalr1.cc"%require "3.8"%language "c++"
%define api.value.automove false
%token <int> VAL%nterm <int> x
%%
x: VAL
-------------------------------------------
bison -o test_automove.cpp test_automove.y
grep -B2 "yylhs.value.int" test_automove.cpp
case 2: // x: VAL#line 14 "test_automove.y" { (yylhs.value.int) = YY_MOVE
((yystack_[0].value.int)); }
bison --versionbison (GNU Bison) 3.8.2
-------------------------------------------
The problem is in skeletons/lalr1.cc where b4_percent_define_ifdef applies
YY_MOVE as long as api.value.automove is defined without considering its value
The default value of api.value.automove is false - omitting the directive does
prevent YY_MOVE from being applied
m4_define([b4_rhs_value],[b4_percent_define_ifdef([api.value.automove],
[YY_MOVE (_b4_rhs_value($@))],
[_b4_rhs_value($@)])])
-------------------------------------------
b4_percent_define_ifdef is defined in skeletons/bison.m4
# _b4_percent_define_ifdef(VARIABLE, IF-TRUE, [IF-FALSE])#
------------------------------------------------------# If the %define variable
VARIABLE is defined, expand IF-TRUE, else expand# IF-FALSE. Don't record usage
of VARIABLE.
-------------------------------------------
I'll send a fix for lalr1.cc shortly to bison-patches that looks like this
111a112,114> # api.value.automove boolean default value false>
b4_percent_define_default([[api.value.automove]], [[false]])>113,115c116,118<
[b4_percent_define_ifdef([api.value.automove],<
[YY_MOVE (_b4_rhs_value($@))],<
[_b4_rhs_value($@)])])---> [b4_percent_define_flag_if([api.value.automove],>
[YY_MOVE (_b4_rhs_value($@))],>
[b4_rhs_value($@)])])
Zartaj
