Merge pull request #8 from sillydan1/implication-operator

Add implication (=>) operator

Author: sillydan1

CMakeLists.txt

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 cmake_minimum_required(VERSION 3.21)
-project(expr VERSION 1.4.0)
+project(expr VERSION 1.5.0)
 include(cmake/CPM.cmake)
 configure_file(src/config.h.in config.h)
 set(CMAKE_CXX_STANDARD 20)

include/drivers/interpreter.h

@@ -47,6 +47,7 @@ namespace expr {
         auto _and(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t override { return and_(a,b); }
         auto _or(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t override { return or_(a,b); }
         auto _xor(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t override { return xor_(a,b); }
+        auto _implies(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t override { return implies_(a,b); }
 
         auto gt(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t override { return gt_(a,b); }
         auto ge(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t override { return ge_(a,b); }

include/symbol_table.h

@@ -80,7 +80,7 @@ namespace expr {
 
     enum class operator_type_t {
         minus, plus, star, slash, percent, hat,
-        _and, _or, _xor, _not,
+        _and, _or, _xor, _not, _implies,
         gt, ge, ne, ee, le, lt,
         parentheses
     };

src/drivers/interpreter.cpp

@@ -84,6 +84,7 @@ namespace expr {
                         case operator_type_t::_or:  v = boolean._or(eval_wrapper(tree.children[0]),  eval_wrapper(tree.children[1])); break;
                         case operator_type_t::_xor: v = boolean._xor(eval_wrapper(tree.children[0]), eval_wrapper(tree.children[1])); break;
                         case operator_type_t::_not: v = boolean._not(eval_wrapper(tree.children[0])); break;
+                        case operator_type_t::_implies: v = boolean._implies(eval_wrapper(tree.children[0]), eval_wrapper(tree.children[1])); break;
                         case operator_type_t::gt: v = comparator.gt(eval_wrapper(tree.children[0]), eval_wrapper(tree.children[1])); break;
                         case operator_type_t::ge: v = comparator.ge(eval_wrapper(tree.children[0]), eval_wrapper(tree.children[1])); break;
                         case operator_type_t::ne: v = comparator.ne(eval_wrapper(tree.children[0]), eval_wrapper(tree.children[1])); break;

src/drivers/z3_driver.cpp

@@ -157,6 +157,7 @@ namespace expr {
                         case operator_type_t::_or:  v = as_z3_expression(tree.children[0]) || as_z3_expression(tree.children[1]); break;
                         case operator_type_t::_xor: v = as_z3_expression(tree.children[0]) xor as_z3_expression(tree.children[1]); break;
                         case operator_type_t::_not: v =!as_z3_expression(tree.children[0]); break;
+                        case operator_type_t::_implies: v = implies(as_z3_expression(tree.children[0]),as_z3_expression(tree.children[1])); break;
                         case operator_type_t::gt: v = (as_z3_expression(tree.children[0]) > as_z3_expression(tree.children[1])); break;
                         case operator_type_t::ge: v = (as_z3_expression(tree.children[0]) >= as_z3_expression(tree.children[1])); break;
                         case operator_type_t::ne: v = (as_z3_expression(tree.children[0]) != as_z3_expression(tree.children[1])); break;

src/operations.h

@@ -44,6 +44,7 @@ namespace expr {
         virtual auto _and(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t = 0;
         virtual auto _or(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t = 0;
         virtual auto _xor(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t = 0;
+        virtual auto _implies(const symbol_value_t& a, const symbol_value_t& b) -> symbol_value_t = 0;
     };
     struct compare_operator {
         virtual auto gt(const symbol_value_t &a, const symbol_value_t &b) -> symbol_value_t = 0;

src/operations/boolean.cpp

@@ -95,6 +95,13 @@ auto t_lt(const T1&, const T2&) {
     throw std::domain_error(ss.str());
     return nullptr; // Must return something
 }
+template<typename T1, typename T2>
+auto t_implies(const T1&, const T2&) {
+    std::ostringstream ss{};
+    ss << "Unable to imply (=>) types " << typeid(T1).name() << " and " << typeid(T2).name();
+    throw std::domain_error(ss.str());
+    return nullptr; // Must return something
+}
 
 template<>
 auto t_and(const bool& a, const bool& b) {
@@ -112,6 +119,11 @@ template<>
 auto t_not(const bool& a) {
     return !a;
 }
+template<>
+auto t_implies(const bool& a, const bool& b) {
+    if(a) return b;
+    return true;
+}
 
 auto t_gt(const int& a, const int& b) {return a > b;}
 auto t_gt(const int& a, const float& b) {return a > b;}
@@ -206,3 +218,8 @@ symbol_value_t lt_(const symbol_value_t& a, const symbol_value_t& b) {
     FUNC_IMPL(a, t_lt, b, res);
     return res;
 }
+symbol_value_t implies_(const symbol_value_t& a, const symbol_value_t& b) {
+    symbol_value_t res{};
+    FUNC_IMPL(a, t_implies, b, res);
+    return res;
+}

src/operations/boolean.h

@@ -33,6 +33,7 @@ expr::symbol_value_t ee_(const expr::symbol_value_t& a, const expr::symbol_value
 expr::symbol_value_t ne_(const expr::symbol_value_t& a, const expr::symbol_value_t& b);
 expr::symbol_value_t le_(const expr::symbol_value_t& a, const expr::symbol_value_t& b);
 expr::symbol_value_t lt_(const expr::symbol_value_t& a, const expr::symbol_value_t& b);
+expr::symbol_value_t implies_(const expr::symbol_value_t& a, const expr::symbol_value_t& b);
 // TODO: These operators are ambiguous with symbol_value_t && std::false_type / std::true_type for some reason.
 //symbol_value_t operator&&(const symbol_value_t& a, const symbol_value_t& b);
 //symbol_value_t operator||(const symbol_value_t& a, const symbol_value_t& b);

src/parser/parser.y

@@ -66,6 +66,7 @@
   AND     "&&"
   OR      "||"
   XOR     "^^"
+  IMPLIES "=>"
   GT      ">"
   GE      ">="
   EE      "=="
@@ -96,6 +97,7 @@
 %left AND
 %left GT GE EE NE LE LT
 %left PLUS MINUS STAR SLASH PERCENT HAT
+%left IMPLIES
 %precedence LPAREN NOT
 %%
 %start unit;
@@ -138,6 +140,7 @@ bin_op:
 | exp LT  exp           { $$ = expr::syntax_tree_t{expr::operator_t{expr::operator_type_t::lt}}.concat($1).concat($3); }
 | exp OR exp            { $$ = expr::syntax_tree_t{expr::operator_t{expr::operator_type_t::_or}}.concat($1).concat($3); }
 | exp XOR exp           { $$ = expr::syntax_tree_t{expr::operator_t{expr::operator_type_t::_xor}}.concat($1).concat($3); }
+| exp IMPLIES exp       { $$ = expr::syntax_tree_t{expr::operator_t{expr::operator_type_t::_implies}}.concat($1).concat($3); }
 | exp AND exp           { $$ = expr::syntax_tree_t{expr::operator_t{expr::operator_type_t::_and}}.concat($1).concat($3); }
 ;
 

src/parser/scanner.l

@@ -147,6 +147,7 @@ type   int|long|float|double|string|bool|var|auto
 "&&"       return yy::parser::make_AND    (loc);
 "||"       return yy::parser::make_OR     (loc);
 "^^"       return yy::parser::make_XOR    (loc);
+"=>"       return yy::parser::make_IMPLIES(loc);
 ">"        return yy::parser::make_GT     (loc);
 ">="       return yy::parser::make_GE     (loc);
 "=="       return yy::parser::make_EE     (loc);