Mercurial > octave
view libinterp/parse-tree/pt-binop.cc @ 23219:3ac9f9ecfae5 stable
maint: Update copyright dates.
author | John W. Eaton <jwe@octave.org> |
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date | Wed, 22 Feb 2017 12:39:29 -0500 |
parents | e9a0469dedd9 |
children | 092078913d54 |
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/* Copyright (C) 1996-2017 John W. Eaton This file is part of Octave. Octave is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. Octave is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Octave; see the file COPYING. If not, see <http://www.gnu.org/licenses/>. */ #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include "error.h" #include "defun.h" #include "ovl.h" #include "ov.h" #include "profiler.h" #include "pt-binop.h" #include "pt-bp.h" #include "pt-walk.h" #include "variables.h" // TRUE means we mark | and & expressions for braindead short-circuit // behavior. static bool Vdo_braindead_shortcircuit_evaluation = true; // Binary expressions. octave_value_list tree_binary_expression::rvalue (int nargout) { octave_value_list retval; if (nargout > 1) error ("binary operator '%s': invalid number of output arguments", oper ().c_str ()); retval = rvalue1 (nargout); return retval; } void tree_binary_expression::matlab_style_short_circuit_warning (const char *op) { warning_with_id ("Octave:possible-matlab-short-circuit-operator", "Matlab-style short-circuit operation performed for operator %s", op); braindead_shortcircuit_warning_issued = true; } octave_value tree_binary_expression::rvalue1 (int) { octave_value retval; if (Vdo_braindead_shortcircuit_evaluation && eligible_for_braindead_shortcircuit) { if (op_lhs) { octave_value a = op_lhs->rvalue1 (); if (a.ndims () == 2 && a.rows () == 1 && a.columns () == 1) { bool result = false; bool a_true = a.is_true (); if (a_true) { if (etype == octave_value::op_el_or) { matlab_style_short_circuit_warning ("|"); return octave_value (true); } } else { if (etype == octave_value::op_el_and) { matlab_style_short_circuit_warning ("&"); return octave_value (false); } } if (op_rhs) { octave_value b = op_rhs->rvalue1 (); result = b.is_true (); } return octave_value (result); } } } if (op_lhs) { octave_value a = op_lhs->rvalue1 (); if (a.is_defined () && op_rhs) { octave_value b = op_rhs->rvalue1 (); if (b.is_defined ()) { BEGIN_PROFILER_BLOCK (tree_binary_expression) // Note: The profiler does not catch the braindead // short-circuit evaluation code above, but that should be // ok. The evaluation of operands and the operator itself // is entangled and it's not clear where to start/stop // timing the operator to make it reasonable. retval = ::do_binary_op (etype, a, b); END_PROFILER_BLOCK } } } return retval; } std::string tree_binary_expression::oper (void) const { return octave_value::binary_op_as_string (etype); } tree_expression * tree_binary_expression::dup (symbol_table::scope_id scope, symbol_table::context_id context) const { tree_binary_expression *new_be = new tree_binary_expression (op_lhs ? op_lhs->dup (scope, context) : 0, op_rhs ? op_rhs->dup (scope, context) : 0, line (), column (), etype); new_be->copy_base (*this); return new_be; } void tree_binary_expression::accept (tree_walker& tw) { tw.visit_binary_expression (*this); } // Boolean expressions. octave_value_list tree_boolean_expression::rvalue (int nargout) { octave_value_list retval; if (nargout > 1) error ("binary operator '%s': invalid number of output arguments", oper ().c_str ()); retval = rvalue1 (nargout); return retval; } octave_value tree_boolean_expression::rvalue1 (int) { octave_value retval; bool result = false; // This evaluation is not caught by the profiler, since we can't find // a reasonable place where to time. Note that we don't want to // include evaluation of LHS or RHS into the timing, but this is // entangled together with short-circuit evaluation here. if (op_lhs) { octave_value a = op_lhs->rvalue1 (); bool a_true = a.is_true (); if (a_true) { if (etype == bool_or) return octave_value (true); } else { if (etype == bool_and) return octave_value (false); } if (op_rhs) { octave_value b = op_rhs->rvalue1 (); result = b.is_true (); } retval = octave_value (result); } return retval; } std::string tree_boolean_expression::oper (void) const { std::string retval = "<unknown>"; switch (etype) { case bool_and: retval = "&&"; break; case bool_or: retval = "||"; break; default: break; } return retval; } tree_expression * tree_boolean_expression::dup (symbol_table::scope_id scope, symbol_table::context_id context) const { tree_boolean_expression *new_be = new tree_boolean_expression (op_lhs ? op_lhs->dup (scope, context) : 0, op_rhs ? op_rhs->dup (scope, context) : 0, line (), column (), etype); new_be->copy_base (*this); return new_be; } DEFUN (do_braindead_shortcircuit_evaluation, args, nargout, doc: /* -*- texinfo -*- @deftypefn {} {@var{val} =} do_braindead_shortcircuit_evaluation () @deftypefnx {} {@var{old_val} =} do_braindead_shortcircuit_evaluation (@var{new_val}) @deftypefnx {} {} do_braindead_shortcircuit_evaluation (@var{new_val}, "local") Query or set the internal variable that controls whether Octave will do short-circuit evaluation of @samp{|} and @samp{&} operators inside the conditions of if or while statements. This feature is only provided for compatibility with @sc{matlab} and should not be used unless you are porting old code that relies on this feature. To obtain short-circuit behavior for logical expressions in new programs, you should always use the @samp{&&} and @samp{||} operators. When called from inside a function with the @qcode{"local"} option, the variable is changed locally for the function and any subroutines it calls. The original variable value is restored when exiting the function. @end deftypefn */) { static bool warned = false; if (! warned) { warned = true; warning_with_id ("Octave:deprecated-function", "do_braindead_shortcircuit_evaluation is obsolete and will be removed from a future version of Octave"); } return SET_INTERNAL_VARIABLE (do_braindead_shortcircuit_evaluation); } /* %!test %! x = 0; %! do_braindead_shortcircuit_evaluation (0); %! if (1 | (x = 1)) %! endif %! assert (x, 1); %! do_braindead_shortcircuit_evaluation (1); %! if (1 | (x = 0)) %! endif %! assert (x, 1); */