feat: String type comparison

Author: DeveloperC286

src/evaluator/expression/infix/mod.rs

@@ -11,6 +11,22 @@ impl Evaluator {
         operator_token: Token,
         right_hand: Expression,
     ) -> Result<Object, EvaluationError> {
+        fn evaluate_same_boolean(operator_token: Token) -> Result<Object, EvaluationError> {
+            match operator_token {
+                Token::Equals => Ok(Object::True),
+                Token::NotEquals => Ok(Object::False),
+                _ => Err(EvaluationError::UnknownOperator),
+            }
+        }
+
+        fn evaluate_opposite_boolean(operator_token: Token) -> Result<Object, EvaluationError> {
+            match operator_token {
+                Token::Equals => Ok(Object::False),
+                Token::NotEquals => Ok(Object::True),
+                _ => Err(EvaluationError::UnknownOperator),
+            }
+        }
+
         match self.evaluate_expression(left_hand)? {
             Object::Integer { value: left_value } => match self.evaluate_expression(right_hand)? {
                 Object::Integer { value: right_value } => match operator_token {
@@ -56,26 +72,24 @@ impl Evaluator {
                 Object::True => evaluate_opposite_boolean(operator_token),
                 _ => Err(EvaluationError::TypeMismatch),
             },
-            _ => Ok(Object::Null),
+            Object::String { value: left_value } => match self.evaluate_expression(right_hand)? {
+                Object::String { value: right_value } => match operator_token {
+                    Token::Equals => match left_value.eq(&right_value) {
+                        true => Ok(Object::True),
+                        false => Ok(Object::False),
+                    },
+                    Token::NotEquals => match left_value.ne(&right_value) {
+                        true => Ok(Object::True),
+                        false => Ok(Object::False),
+                    },
+                    _ => Err(EvaluationError::UnknownOperator),
+                },
+                _ => Err(EvaluationError::TypeMismatch),
+            },
+            _ => Err(EvaluationError::UnknownOperator),
         }
     }
 }
 
-fn evaluate_same_boolean(operator_token: Token) -> Result<Object, EvaluationError> {
-    match operator_token {
-        Token::Equals => Ok(Object::True),
-        Token::NotEquals => Ok(Object::False),
-        _ => Err(EvaluationError::UnknownOperator),
-    }
-}
-
-fn evaluate_opposite_boolean(operator_token: Token) -> Result<Object, EvaluationError> {
-    match operator_token {
-        Token::Equals => Ok(Object::False),
-        Token::NotEquals => Ok(Object::True),
-        _ => Err(EvaluationError::UnknownOperator),
-    }
-}
-
 #[cfg(test)]
 mod tests;

src/evaluator/expression/infix/tests/mod.rs

@@ -40,7 +40,31 @@ fn test_evaluator_infix_integer_expressions(code: &str, snapshot_name: &str) {
     case("(1 < 2) == true", "test_evaluator_infix_boolean_expressions_case17"),
     case("(1 < 2) == false", "test_evaluator_infix_boolean_expressions_case18"),
     case("(1 > 2) == true", "test_evaluator_infix_boolean_expressions_case19"),
-    case("(1 > 2) == false", "test_evaluator_infix_boolean_expressions_case20")
+    case("(1 > 2) == false", "test_evaluator_infix_boolean_expressions_case20"),
+    case(
+        "\"name\" == \"name\"",
+        "test_evaluator_infix_boolean_expressions_case21"
+    ),
+    case(
+        "\"this is a string\" == \"this is a string\"",
+        "test_evaluator_infix_boolean_expressions_case22"
+    ),
+    case(
+        "\"first\" != \"last\"",
+        "test_evaluator_infix_boolean_expressions_case23"
+    ),
+    case(
+        "\"string123\" != \"\\tstring123\"",
+        "test_evaluator_infix_boolean_expressions_case24"
+    ),
+    case(
+        "\"string123\" != \"string123\"",
+        "test_evaluator_infix_boolean_expressions_case25"
+    ),
+    case(
+        "\"name\" == \"name123\"",
+        "test_evaluator_infix_boolean_expressions_case26"
+    )
 )]
 fn test_evaluator_infix_boolean_expressions(code: &str, snapshot_name: &str) {
     assert_expected_returned_object!(code, snapshot_name);
@@ -58,6 +82,14 @@ fn test_evaluator_infix_boolean_expressions(code: &str, snapshot_name: &str) {
     case(
         "if (10 > 1) { return TRUE + 5; } return 1;",
         "test_evaluator_infix_type_mismatch_expressions_case4"
+    ),
+    case(
+        "\"this is a string\" == 3",
+        "test_evaluator_infix_type_mismatch_expressions_case5"
+    ),
+    case(
+        "82 != \"this is a string\"",
+        "test_evaluator_infix_type_mismatch_expressions_case6"
     )
 )]
 fn test_evaluator_infix_type_mismatch_expressions(code: &str, snapshot_name: &str) {

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_boolean_expressions_case21.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Ok(
+    True,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_boolean_expressions_case22.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Ok(
+    True,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_boolean_expressions_case23.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Ok(
+    True,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_boolean_expressions_case24.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Ok(
+    True,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_boolean_expressions_case25.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Ok(
+    False,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_boolean_expressions_case26.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Ok(
+    False,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_type_mismatch_expressions_case5.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Err(
+    TypeMismatch,
+)

src/evaluator/expression/infix/tests/snapshots/monkey_interpreter__evaluator__expression__infix__tests__test_evaluator_infix_type_mismatch_expressions_case6.snap

@@ -0,0 +1,8 @@
+---
+source: src/evaluator/expression/infix/tests/mod.rs
+expression: "evaluator.evaluate(crate::syntax_analysis::SyntaxAnalysis::from(crate::lexical_analysis::LexicalAnalysis::from(code).unwrap()).unwrap())"
+
+---
+Err(
+    TypeMismatch,
+)