Add operator < to calc

examples/calc/AST.cpp

@@ -69,6 +69,8 @@ double Binop::eval(const Variables& vars, const Functions& funs) const {
         return left / right;
     else if (m_op == "^")
         return std::pow(left, right);
+    else if (m_op == "<")
+        return left < right ? 1 : 0;
     return 0;
 }
 

examples/calc/calcLexer.lxs

@@ -9,6 +9,7 @@ MINUS = -
 TIMES = \*
 DIVIDE = /
 EXPONENT = ^
+LT = <
 ASSIGN = =
 NUM = (0|[1-9][0-9]*)(\.[0-9]+)?
 IDENT = [a-zA-Z_][a-zA-Z0-9_]*

examples/calc/calcParser.pds

@@ -4,6 +4,7 @@ precedence:
     right "EXPONENT"
     left "TIMES" "DIVIDE"
     left "PLUS" "MINUS"
+    nonassoc "LT"
 
 start: <start>
 grammar:
@@ -27,6 +28,7 @@ grammar:
              | <expr> "TIMES" <expr>                     [binop]
              | <expr> "DIVIDE" <expr>                    [binop]
              | <expr> "EXPONENT" <expr>                  [binop]
+             | <expr> "LT" <expr>                        [binop]
              | "IDENT"                                   [expr_simple]
              | "NUM"                                     [expr_simple]
              | "MINUS" <expr>                            [umin, right 1]

examples/calc/parser.cpp

@@ -72,6 +72,9 @@ Parser::Value Parser::reduce_binop(std::deque<Token> subparts) {
         case calcParser_Symbol::T_EXPONENT:
             op = "^";
             break;
+        case calcParser_Symbol::T_LT:
+            op = "<";
+            break;
         default:
             break;
     }