Supported 'logical or/and'.

language/interpreter.cc

@@ -15,6 +15,8 @@ struct Eval
             case Function:           return eval_function(ast, env);
             case FunctionCall:       return eval_function_call(ast, env);
             case Assignment:         return eval_assignment(ast, env);
+            case LogicalOr:          return eval_logical_or(ast, env);
+            case LogicalAnd:         return eval_logical_and(ast, env);
             case Condition:          return eval_condition(ast, env);
             case BinExpresion:       return eval_bin_expression(ast, env);
             case Identifier:         return eval_identifier(ast, env);
@@ -119,9 +121,37 @@ private:
         throw runtime_error(msg);
     }
 
+    static Value eval_logical_or(const Ast& ast, shared_ptr<Environment> env) {
+        if (ast.nodes.size() == 1) {
+            return eval(*ast.nodes[0], env);
+        } else {
+            Value ret;
+            for (auto node: ast.nodes) {
+                ret = eval(*node, env);
+                if (ret.to_bool()) {
+                    return ret;
+                }
+            }
+            return ret;
+        }
+    }
+
+    static Value eval_logical_and(const Ast& ast, shared_ptr<Environment> env) {
+        Value ret;
+        for (auto node: ast.nodes) {
+            ret = eval(*node, env);
+            if (!ret.to_bool()) {
+                return ret;
+            }
+        }
+        return ret;
+    }
+
     static Value eval_condition(const Ast& ast, shared_ptr<Environment> env) {
-        auto lhs = eval(*ast.nodes[0], env);
+        if (ast.nodes.size() == 1) {
-        if (ast.nodes.size() > 1) {
+            return eval(*ast.nodes[0], env);
+        } else {
+            auto lhs = eval(*ast.nodes[0], env);
             auto ope = eval(*ast.nodes[1], env).to_string();
             auto rhs = eval(*ast.nodes[2], env);
 
@@ -137,11 +167,10 @@ private:
                 return Value(lhs >= rhs);
             } else if (ope == ">") {
                 return Value(lhs > rhs);
+            } else {
+                throw std::logic_error("invalid internal condition.");
             }
-
-            throw std::logic_error("invalid internal condition.");
         }
-        return lhs; // Any
     }
 
     static Value eval_bin_expression(const Ast& ast, shared_ptr<Environment> env) {

language/parser.cc

@@ -18,7 +18,9 @@ static auto g_grammar = R"(
     FUNCTION_CALL         <-  IDENTIFIER ARGUMENTS
     ARGUMENTS             <-  '(' _ (EXPRESSION (', ' _ EXPRESSION)*)? ')' _
 
-    PRIMARY               <-  CONDITION (CONDITION_OPERATOR CONDITION)?
+    PRIMARY               <-  LOGICAL_OR ('||' _ LOGICAL_OR)*
+    LOGICAL_OR            <-  LOGICAL_AND ('&&' _  LOGICAL_AND)*
+    LOGICAL_AND           <-  CONDITION (CONDITION_OPERATOR CONDITION)*
     CONDITION             <-  TERM (TERM_OPERATOR TERM)*
     TERM                  <-  FACTOR (FACTOR_OPERATOR FACTOR)*
     FACTOR                <-  WHILE / IF / FUNCTION / FUNCTION_CALL / NUMBER / BOOLEAN / STRING / INTERPOLATED_STRING / IDENTIFIER / '(' _ EXPRESSION ')' _
@@ -72,7 +74,9 @@ peg& get_parser()
             { peg::AstNodeType::Regular,     "PARAMETERS",           Undefined          },
             { peg::AstNodeType::Regular,     "FUNCTION_CALL",        FunctionCall       },
             { peg::AstNodeType::Regular,     "ARGUMENTS",            Undefined          },
-            { peg::AstNodeType::Optimizable, "PRIMARY",              Condition          },
+            { peg::AstNodeType::Optimizable, "PRIMARY",              LogicalOr          },
+            { peg::AstNodeType::Optimizable, "LOGICAL_OR",           LogicalAnd         },
+            { peg::AstNodeType::Optimizable, "LOGICAL_AND",          Condition          },
             { peg::AstNodeType::Optimizable, "CONDITION",            BinExpresion       },
             { peg::AstNodeType::Optimizable, "TERM",                 BinExpresion       },
             { peg::AstNodeType::Token,       "CONDITION_OPERATOR",   Undefined          },

language/parser.hpp

@@ -3,7 +3,8 @@
 enum AstTag
 {
    Undefined,
-   Statements, While, If, FunctionCall, Assignment, Condition, BinExpresion,
+   Statements, While, If, FunctionCall, Assignment,
+   LogicalOr, LogicalAnd, Condition, BinExpresion,
    Identifier, InterpolatedString,
    Number, Boolean, Function
 };