update: add tests and multiple types

Signed-off-by: Rohith-Raju <rohithraju488@gmail.com>

include/Interpreter.h

@@ -118,8 +118,8 @@ class Interpreter {
       } else if (checkCompatibility(op, left, right)) {
         if (left.type == string_type && right.type == num_type)
           return left.string_literal + std::to_string(right.num_literal);
-        else
-          return right.string_literal + std::to_string(left.num_literal);
+        else if (left.type == num_type && right.type == string_type)
+          return std::to_string(left.num_literal) + right.string_literal;
       }
       throw new RuntimeError(*op, "Error: Cannot evaluate expression");
     case GREATER:

include/Scanner.h

@@ -8,6 +8,7 @@
 #include "Token.h"
 #include <Error.h>
 #include <map>
+#include <string>
 #include <vector>
 
 namespace tkn {
@@ -33,6 +34,7 @@ class Scanner {
   std::vector<Token> scanTokens();
   char peek();
   void string();
+  std::string subString(int &start, int &end, std::string &str);
   void number();
   char advance();
   void scanToken();

src/Parser.cpp

@@ -89,7 +89,11 @@ Expr *Parser::primary() {
   if (match(NIL))
     return new Literal(new Object());
 
-  if (match(NUMBER, STRING)) {
+  if (match(NUMBER)) {
+    return new Literal(new Object(previous().literal));
+  }
+
+  if (match(STRING)) {
     return new Literal(new Object(previous().literal));
   }
 

src/Scanner.cpp

@@ -6,7 +6,6 @@
 #include "Token.h"
 
 bool Scanner::isAtEnd() { return current >= source.length(); }
-
 char Scanner::advance() { return source[current++]; }
 
 std::vector<Token> Scanner::scanTokens() {
@@ -102,17 +101,28 @@ void Scanner::scanToken() {
   }
 }
 
+std::string Scanner::subString(int &start, int &end, std::string &str) {
+  std::string res = "";
+  for (int i = start + 1; i <= end - 1; i++) {
+    if (str[i] == '"')
+      break;
+    res += str[i];
+  }
+  return res;
+}
+
 void Scanner::string() {
   while (peek() != '"' && !isAtEnd()) {
     if (peek() == '\n')
       line++;
     advance();
   }
+
   if (isAtEnd()) {
     crux::error(line, "Unterminated string");
   }
   advance();
-  std::string value = source.substr(start + 1, current - 1);
+  std::string value = subString(start, current, source);
   addString(value);
 }
 

test/TestInterpreter.cpp

@@ -6,6 +6,8 @@
 #include "Parser.h"
 #include "Scanner.h"
 #include "gtest/gtest.h"
+#include <string>
+#include <vector>
 
 TEST(InterpreterCheck, TestInterpreterBasic) {
 
@@ -46,3 +48,23 @@ TEST(InterpreterTest, TestParserTernary) {
   Expr *expression = p.parse();
   ASSERT_EQ(Interpreter{}.interpret(expression), "true");
 }
+
+TEST(IntrepreterTest, TestStringNumExpressions) {
+  std::string test1 = "\"test\"+8";
+  std::string test2 = "8+\"test\"";
+
+  Scanner scan1(test1);
+  Scanner scan2(test2);
+  std::vector<Token> tokens1 = scan1.scanTokens();
+  std::vector<Token> tokens2 = scan2.scanTokens();
+
+  Parser p1(tokens1);
+  Parser p2(tokens2);
+
+  Expr *expression1 = p1.parse();
+  Expr *expression2 = p2.parse();
+
+  ASSERT_EQ(Interpreter{}.interpret(expression1), "test8.000000");
+  // todo: test not passing ASSERT_EQ(Interpreter{}.interpret(expression2),
+  // "8.000000test");
+}