Implements return statement

src/Binder/Binder.cpp

@@ -25,6 +25,7 @@ BoundStatement* Binder::BindStatement(ParsedStatement* statement){
         case ParsedStatementKind ::Expression: return this -> BindExpressionStatement(statement);
         case ParsedStatementKind::Assignment: return this -> BindAssignmentStatement(statement);
         case ParsedStatementKind ::FunctionDeclaration: return this->BindFunctionDeclarationStatement(statement);
+        case ParsedStatementKind::Return: return this -> BindReturnStatement(statement);
 
         case ParsedStatementKind::Bad: return new BoundBadStatement();
     }
@@ -105,6 +106,31 @@ BoundStatement *Binder::BindFunctionDeclarationStatement(ParsedStatement *statem
     return new BoundBadStatement();
 }
 
+BoundStatement *Binder::BindReturnStatement(ParsedStatement* statement){
+    auto expression = ((ParsedReturnStatement*)statement)->GetExpression();
+    shared_ptr<ScriptType> currentReturnType;
+    if (this->_currentFunction == nullptr){
+        currentReturnType = this->_scriptData->GetReturnType();
+    } else{
+        currentReturnType = this->_currentFunction;
+    }
+    if (expression == nullptr && currentReturnType != nullptr){
+        this -> _scriptData -> Diagnostics -> LogError(DiagnosticCode::InvalidReturnType, statement->GetStartPosition(), statement->GetLength());
+        return new BoundBadStatement();
+    }
+    auto boundExpression = this->BindExpression(expression);
+    auto expresionType = boundExpression->GetType();
+    if (currentReturnType == nullptr){
+        currentReturnType.swap(expresionType);
+        return new BoundReturnStatement(boundExpression);
+    }
+    if (currentReturnType.get()->operator!=(expresionType.get())){
+        this -> _scriptData -> Diagnostics -> LogError(DiagnosticCode::InvalidReturnType, statement->GetStartPosition(), statement->GetLength());
+        return new BoundBadStatement();
+    }
+    return new BoundReturnStatement(boundExpression);
+}
+
 BoundExpression* Binder::BindExpression(ParsedExpression* expression){
     switch (expression -> GetKind()){
         case ParsedExpressionKind ::LiteralInteger:

src/Binder/Binder.hpp

@@ -10,6 +10,7 @@
 class Binder {
     Script* _scriptData;
     BoundScope* _scope;
+    shared_ptr<FunctionScriptType> _currentFunction;
 
     ~Binder();
 
@@ -18,6 +19,7 @@ class Binder {
     BoundStatement *BindExpressionStatement(ParsedStatement *statement);
     BoundStatement *BindAssignmentStatement(ParsedStatement *statement);
     BoundStatement *BindFunctionDeclarationStatement(ParsedStatement * statement);
+    BoundStatement *BindReturnStatement(ParsedStatement *statement);
 
     BoundExpression *BindExpression(ParsedExpression *expression);
     BoundExpression *BindVariableExpression(VariableExpression *expression);

src/Binder/BoundStatements/BoundStatement.hpp

@@ -1,9 +1,8 @@
-#include <utility>
 
 
 #ifndef PORYGONLANG_BOUNDSTATEMENT_HPP
 #define PORYGONLANG_BOUNDSTATEMENT_HPP
-
+#include <utility>
 #include <vector>
 #include "../BoundExpressions/BoundExpression.hpp"
 #include "../BoundVariables/BoundVariableKey.hpp"
@@ -18,6 +17,7 @@ enum class BoundStatementKind{
     Expression,
     Assignment,
     FunctionDeclaration,
+    Return,
 };
 
 class BoundStatement{
@@ -116,6 +116,25 @@ public:
     }
 };
 
+class BoundReturnStatement : public BoundStatement{
+    BoundExpression* _expression;
+public:
+    explicit BoundReturnStatement(BoundExpression* expression){
+        _expression = expression;
+    }
+    ~BoundReturnStatement() final{
+        delete _expression;
+    }
+
+    BoundStatementKind GetKind() final{
+        return BoundStatementKind ::Return;
+    }
+
+    BoundExpression* GetExpression(){
+        return _expression;
+    }
+};
+
 #include "BoundFunctionDeclarationStatement.hpp"
 
 #endif //PORYGONLANG_BOUNDSTATEMENT_HPP

src/Diagnostics/DiagnosticCode.hpp

@@ -19,6 +19,7 @@ enum class DiagnosticCode{
     ParameterCountMismatch,
     ParameterTypeMismatch,
     CantIndex,
+    InvalidReturnType,
 };
 
 #endif //PORYGONLANG_DIAGNOSTICCODE_HPP

src/Evaluator/Evaluator.cpp

@@ -1,8 +1,4 @@
 #include <utility>
-
-#include <utility>
-
-
 #include <memory>
 #include "Evaluator.hpp"
 #include "EvaluationException.hpp"
@@ -18,12 +14,15 @@ void Evaluator::Evaluate(BoundScriptStatement *statement) {
 }
 
 void Evaluator::EvaluateStatement(BoundStatement *statement) {
+    if (this->_hasReturned)
+        return;
     switch (statement->GetKind()){
         case BoundStatementKind ::Script: throw; // Should never happen
         case BoundStatementKind ::Block: return this -> EvaluateBlockStatement((BoundBlockStatement*)statement);
         case BoundStatementKind ::Expression: return this -> EvaluateExpressionStatement((BoundExpressionStatement*)statement);
         case BoundStatementKind ::Assignment: return this -> EvaluateAssignmentStatement((BoundAssignmentStatement*)statement);
         case BoundStatementKind ::FunctionDeclaration: return this->EvaluateFunctionDeclarationStatement((BoundFunctionDeclarationStatement*)statement);
+        case BoundStatementKind::Return: return this -> EvaluateReturnStatement((BoundReturnStatement*)statement);
 
         case BoundStatementKind::Bad:
             throw;
@@ -34,6 +33,8 @@ void Evaluator::EvaluateBlockStatement(BoundBlockStatement* statement) {
     this->_evaluationScope->OuterScope();
     for (auto s: statement->GetStatements()){
         this -> EvaluateStatement(s);
+        if (this->_hasReturned)
+            break;
     }
     this->_evaluationScope->InnerScope();
 }
@@ -65,6 +66,16 @@ void Evaluator::EvaluateFunctionDeclarationStatement(BoundFunctionDeclarationSta
     }
 }
 
+void Evaluator::EvaluateReturnStatement(BoundReturnStatement* statement){
+    auto expression = statement->GetExpression();
+    this->_hasReturned = true;
+    if (expression == nullptr){
+        return;
+    }
+    auto value = this -> EvaluateExpression(expression);
+    this -> _returnValue = value;
+}
+
 shared_ptr<EvalValue> Evaluator::EvaluateExpression(BoundExpression *expression) {
     auto type = expression -> GetType();
     switch (type->GetClass()){
@@ -174,11 +185,13 @@ shared_ptr<EvalValue> Evaluator::EvaluateFunctionCallExpression(BoundExpression*
         this->_evaluationScope->CreateVariable(key->GetScopeId(), key->GetIdentifier(), parameter->Clone());
     }
     this->EvaluateBlockStatement(function->GetInnerBlock().get());
-    return nullptr;
+    this->_hasReturned = false;
-
+    auto r = this -> _returnValue;
+    this -> _returnValue = nullptr;
+    return r;
 }
 
-EvalValue* Evaluator::EvaluateFunction(ScriptFunctionEvalValue *function, vector<EvalValue *> parameters) {
+shared_ptr<EvalValue> Evaluator::EvaluateFunction(ScriptFunctionEvalValue *function, vector<EvalValue *> parameters) {
     auto type = std::dynamic_pointer_cast<FunctionScriptType>(function->GetType());
     auto parameterTypes = type->GetParameterTypes();
     auto parameterKeys = type->GetParameterKeys();
@@ -192,7 +205,10 @@ EvalValue* Evaluator::EvaluateFunction(ScriptFunctionEvalValue *function, vector
         this->_evaluationScope->CreateVariable(key->GetScopeId(), key->GetIdentifier(), parameter->Clone());
     }
     this->EvaluateBlockStatement(function->GetInnerBlock().get());
-    return nullptr;
+    this->_hasReturned = false;
+    auto r = this -> _returnValue;
+    this -> _returnValue = nullptr;
+    return r;
 }
 
 shared_ptr<EvalValue> Evaluator::EvaluateIndexExpression(BoundExpression *expression) {

src/Evaluator/Evaluator.hpp

@@ -15,7 +15,8 @@
 using namespace std;
 
 class Evaluator {
-    shared_ptr<EvalValue> _result;
+    shared_ptr<EvalValue> _returnValue;
+    bool _hasReturned;
     shared_ptr<EvalValue> _lastValue;
 
     Script* _scriptData;
@@ -26,6 +27,7 @@ class Evaluator {
     void EvaluateExpressionStatement(BoundExpressionStatement* statement);
     void EvaluateAssignmentStatement(BoundAssignmentStatement* statement);
     void EvaluateFunctionDeclarationStatement(BoundFunctionDeclarationStatement *statement);
+    void EvaluateReturnStatement(BoundReturnStatement *statement);
 
     shared_ptr<EvalValue> EvaluateExpression(BoundExpression* expression);
     shared_ptr<NumericEvalValue> EvaluateIntegerExpression(BoundExpression* expression);
@@ -47,6 +49,8 @@ class Evaluator {
 public:
     explicit Evaluator(Script* script){
         _scriptData = script;
+        _hasReturned = false;
+        _returnValue = nullptr;
         _evaluationScope = nullptr;
     }
 
@@ -55,7 +59,7 @@ public:
     }
 
     void Evaluate(BoundScriptStatement* statement);
-    EvalValue* EvaluateFunction(ScriptFunctionEvalValue* func, vector<EvalValue*> parameters);
+    shared_ptr<EvalValue> EvaluateFunction(ScriptFunctionEvalValue* func, vector<EvalValue*> parameters);
 
     EvalValue* GetLastValue(){
         return _lastValue.get();

src/Parser/ParsedStatements/ParsedStatement.hpp

@@ -15,7 +15,8 @@ enum class ParsedStatementKind{
     Block,
     Expression,
     Assignment,
-    FunctionDeclaration
+    FunctionDeclaration,
+    Return
 };
 
 class ParsedStatement {
@@ -166,4 +167,24 @@ public:
     }
 };
 
+class ParsedReturnStatement : public ParsedStatement{
+    ParsedExpression* _expression;
+public:
+    ParsedReturnStatement(ParsedExpression* expression, unsigned int start, unsigned int length) : ParsedStatement(start, length){
+        _expression = expression;
+    }
+
+    ~ParsedReturnStatement() final{
+        delete _expression;
+    }
+
+    ParsedStatementKind GetKind() final{
+        return ParsedStatementKind ::Return;
+    }
+
+    ParsedExpression* GetExpression(){
+        return _expression;
+    }
+};
+
 #endif //PORYGONLANG_PARSEDSTATEMENT_HPP

src/Parser/Parser.cpp

@@ -33,6 +33,7 @@ ParsedStatement* Parser::ParseStatement(IToken* current){
     switch (currentKind){
         case TokenKind ::LocalKeyword: return this -> ParseAssignment(current);
         case TokenKind ::FunctionKeyword: return this -> ParseFunctionDeclaration(current);
+        case TokenKind ::ReturnKeyword: return this->ParseReturnStatement(current);
         default: break;
     }
     if (this->Peek()->GetKind() == TokenKind::AssignmentToken){
@@ -134,7 +135,13 @@ ParsedStatement *Parser::ParseFunctionDeclaration(IToken *current) {
     }
     auto functionIdentifier = ((IdentifierToken*) functionIdentifierToken)->Value;
     return new ParsedFunctionDeclarationStatement(HashedString(functionIdentifier), parameters, (ParsedBlockStatement*)block, start, block->GetEndPosition() - start);
+}
 
+ParsedStatement* Parser::ParseReturnStatement(IToken* current){
+    //TODO: if next token is on a different line, don't parse it as return expression.
+    auto expression = this->ParseExpression(this->Next());
+    auto start = current->GetStartPosition();
+    return new ParsedReturnStatement(expression, start, expression->GetEndPosition() - start);
 }
 
 ParsedExpression* Parser::ParseExpression(IToken* current){

src/Parser/Parser.hpp

@@ -29,6 +29,7 @@ class Parser {
     ParsedStatement* ParseAssignment(IToken* current);
     ParsedStatement *ParseBlock(const vector<TokenKind>& endTokens);
     ParsedStatement* ParseFunctionDeclaration(IToken* current);
+    ParsedStatement *ParseReturnStatement(IToken *current);
 
     ParsedExpression* ParseExpression(IToken* current);
     ParsedExpression* ParseBinaryExpression(IToken* current, OperatorPrecedence parentPrecedence);

src/Script.cpp

@@ -72,7 +72,7 @@ bool Script::HasFunction(const string &key) {
     return f != _scriptVariables->end() && f.operator->()->second->GetType()->GetClass() == TypeClass ::Function;
 }
 
-EvalValue *Script::CallFunction(const string &key, vector<EvalValue *> variables) {
+shared_ptr<EvalValue> Script::CallFunction(const string &key, vector<EvalValue *> variables) {
     auto var = (ScriptFunctionEvalValue*)GetVariable(key);
     return this->_evaluator->EvaluateFunction(var, std::move(variables));
 }
@@ -104,7 +104,7 @@ extern "C" {
 
     EvalValue* CallFunction(Script* script, const char* key, EvalValue* parameters[], int parameterCount){
         std::vector<EvalValue*> v(parameters, parameters + parameterCount);
-        return script->CallFunction(key, v);
+        return script->CallFunction(key, v).get();
     }
 }
 

src/Script.hpp

@@ -20,6 +20,7 @@ class Script {
     Evaluator* _evaluator;
     unordered_map<int, shared_ptr<EvalValue>>* _scriptVariables;
     BoundScriptStatement* _boundScript;
+    shared_ptr<ScriptType> _returnType;
 
     explicit Script();
     void Parse(string script);
@@ -29,6 +30,10 @@ public:
 
     ~Script();
 
+    shared_ptr<ScriptType> GetReturnType(){
+        return _returnType;
+    }
+
     void Evaluate();
 
     EvalValue* GetLastValue();
@@ -36,10 +41,8 @@ public:
     EvalValue* GetVariable(const string& key);
     bool HasVariable(const string& key);
 
-    EvalValue* CallFunction(const string& key, vector<EvalValue*> variables);
+    shared_ptr<EvalValue> CallFunction(const string& key, vector<EvalValue*> variables);
     bool HasFunction(const string& key);
-
-
 };
 
 

tests/integration/Functions.cpp

@@ -57,5 +57,32 @@ TEST_CASE( "Define script function and call from extern", "[integration]" ) {
     delete script;
 }
 
+TEST_CASE( "Define script function and return", "[integration]" ) {
+    Script* script = Script::Create(
+            "val = 0\n"
+            "function add(number a, number b) \n"
+            "return a + b \n"
+            "val = val + 1\n"
+            "end");
+    REQUIRE(!script->Diagnostics -> HasErrors());
+    script->Evaluate();
+
+    REQUIRE(script->HasFunction("add"));
+    auto toAddVal = new IntegerEvalValue(5);
+    auto toAddVal2 = new IntegerEvalValue(6);
+    auto result = script->CallFunction("add", {toAddVal, toAddVal2});
+    delete toAddVal;
+    delete toAddVal2;
+
+    REQUIRE(result->GetType()->GetClass() == TypeClass::Number);
+    REQUIRE(result->EvaluateInteger() == 11);
+
+    auto variable = script->GetVariable("val");
+    REQUIRE(variable->GetType()->GetClass() == TypeClass::Number);
+    REQUIRE(variable->EvaluateInteger() == 0);
+
+    delete script;
+}
+
 
 #endif