Implements if, elseif and else statements

src/Binder/Binder.cpp

@@ -26,6 +26,7 @@ BoundStatement* Binder::BindStatement(ParsedStatement* statement){
         case ParsedStatementKind::Assignment: return this -> BindAssignmentStatement(statement);
         case ParsedStatementKind ::FunctionDeclaration: return this->BindFunctionDeclarationStatement(statement);
         case ParsedStatementKind::Return: return this -> BindReturnStatement(statement);
+        case ParsedStatementKind::Conditional: return this -> BindConditionalStatement(statement);
 
         case ParsedStatementKind::Bad: return new BoundBadStatement();
     }
@@ -131,6 +132,21 @@ BoundStatement *Binder::BindReturnStatement(ParsedStatement* statement){
     return new BoundReturnStatement(boundExpression);
 }
 
+BoundStatement *Binder::BindConditionalStatement(ParsedStatement* statement) {
+    auto conditionalStatement = (ParsedConditionalStatement*)statement;
+    auto boundCondition = this -> BindExpression(conditionalStatement -> GetCondition());
+    if (boundCondition->GetType() -> GetClass() != TypeClass::Bool){
+        this -> _scriptData -> Diagnostics -> LogError(DiagnosticCode::ConditionNotABool, statement->GetStartPosition(), statement->GetLength());
+        return new BoundBadStatement();
+    }
+    auto boundBlock = this -> BindStatement(conditionalStatement->GetBlock());
+    BoundStatement* elseStatement = nullptr;
+    if (conditionalStatement->GetElseStatement() != nullptr){
+        elseStatement = this -> BindStatement(conditionalStatement->GetElseStatement());
+    }
+    return new BoundConditionalStatement(boundCondition, boundBlock, elseStatement);
+}
+
 BoundExpression* Binder::BindExpression(ParsedExpression* expression){
     switch (expression -> GetKind()){
         case ParsedExpressionKind ::LiteralInteger:
@@ -351,3 +367,4 @@ BoundExpression *Binder::BindIndexExpression(IndexExpression *expression) {
     auto resultType = shared_ptr<ScriptType>(indexer->GetType()->GetIndexedType(index->GetType().get()));
     return new BoundIndexExpression(indexer, index, resultType, expression->GetStartPosition(), expression->GetLength());
 }
+

src/Binder/Binder.hpp

@@ -20,6 +20,7 @@ class Binder {
     BoundStatement *BindAssignmentStatement(ParsedStatement *statement);
     BoundStatement *BindFunctionDeclarationStatement(ParsedStatement * statement);
     BoundStatement *BindReturnStatement(ParsedStatement *statement);
+    BoundStatement *BindConditionalStatement(ParsedStatement *statement);
 
     BoundExpression *BindExpression(ParsedExpression *expression);
     BoundExpression *BindVariableExpression(VariableExpression *expression);

src/Binder/BoundStatements/BoundStatement.hpp

@@ -18,6 +18,7 @@ enum class BoundStatementKind{
     Assignment,
     FunctionDeclaration,
     Return,
+    Conditional,
 };
 
 class BoundStatement{
@@ -135,6 +136,41 @@ public:
     }
 };
 
+class BoundConditionalStatement : public BoundStatement{
+    BoundExpression* _condition;
+    BoundStatement* _block;
+    BoundStatement* _elseStatement;
+public:
+    explicit BoundConditionalStatement(BoundExpression* condition, BoundStatement* block, BoundStatement* next){
+        _condition = condition;
+        _block = block;
+        _elseStatement = next;
+    }
+
+    ~BoundConditionalStatement() final{
+        delete _condition;
+        delete _block;
+        delete _elseStatement;
+    }
+
+    BoundStatementKind GetKind() final{
+        return BoundStatementKind ::Conditional;
+    }
+
+    BoundExpression* GetCondition(){
+        return _condition;
+    }
+
+    BoundStatement* GetBlock(){
+        return _block;
+    }
+
+    BoundStatement* GetElseStatement(){
+        return _elseStatement;
+    }
+};
+
+
 #include "BoundFunctionDeclarationStatement.hpp"
 
 #endif //PORYGONLANG_BOUNDSTATEMENT_HPP

src/Diagnostics/DiagnosticCode.hpp

@@ -20,6 +20,7 @@ enum class DiagnosticCode{
     ParameterTypeMismatch,
     CantIndex,
     InvalidReturnType,
+    ConditionNotABool,
 };
 
 #endif //PORYGONLANG_DIAGNOSTICCODE_HPP

src/Evaluator/Evaluator.cpp

@@ -23,6 +23,7 @@ void Evaluator::EvaluateStatement(BoundStatement *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::Conditional: return this -> EvaluateConditionalStatement((BoundConditionalStatement*)statement);
 
         case BoundStatementKind::Bad:
             throw;
@@ -76,6 +77,18 @@ void Evaluator::EvaluateReturnStatement(BoundReturnStatement* statement){
     this -> _returnValue = value;
 }
 
+void Evaluator::EvaluateConditionalStatement(BoundConditionalStatement *statement) {
+    auto condition = statement->GetCondition();
+    if (EvaluateBoolExpression(condition) -> EvaluateBool()){
+        this -> EvaluateStatement(statement->GetBlock());
+    } else{
+        auto elseStatement = statement -> GetElseStatement();
+        if (elseStatement != nullptr){
+            this->EvaluateStatement(elseStatement);
+        }
+    }
+}
+
 shared_ptr<EvalValue> Evaluator::EvaluateExpression(BoundExpression *expression) {
     auto type = expression -> GetType();
     switch (type->GetClass()){
@@ -217,3 +230,4 @@ shared_ptr<EvalValue> Evaluator::EvaluateIndexExpression(BoundExpression *expres
     auto indexable = this -> EvaluateExpression(indexExpression->GetIndexableExpression());
     return shared_ptr<EvalValue>(indexable -> IndexValue(index.get()));
 }
+

src/Evaluator/Evaluator.hpp

@@ -28,6 +28,7 @@ class Evaluator {
     void EvaluateAssignmentStatement(BoundAssignmentStatement* statement);
     void EvaluateFunctionDeclarationStatement(BoundFunctionDeclarationStatement *statement);
     void EvaluateReturnStatement(BoundReturnStatement *statement);
+    void EvaluateConditionalStatement(BoundConditionalStatement *statement);
 
     shared_ptr<EvalValue> EvaluateExpression(BoundExpression* expression);
     shared_ptr<NumericEvalValue> EvaluateIntegerExpression(BoundExpression* expression);

src/Parser/ParsedStatements/ParsedStatement.hpp

@@ -16,7 +16,8 @@ enum class ParsedStatementKind{
     Expression,
     Assignment,
     FunctionDeclaration,
-    Return
+    Return,
+    Conditional
 };
 
 class ParsedStatement {
@@ -187,4 +188,47 @@ public:
     }
 };
 
+class ParsedConditionalStatement : public ParsedStatement{
+    ParsedExpression* _condition;
+    ParsedStatement* _block;
+    // This can be either else if or else
+    ParsedStatement* _elseStatement;
+public:
+    ParsedConditionalStatement(ParsedExpression* condition, ParsedStatement* block, unsigned int start, unsigned int length)
+    : ParsedStatement(start, length){
+        _condition = condition;
+        _block = block;
+        _elseStatement = nullptr;
+    }
+
+    ParsedConditionalStatement(ParsedExpression* condition, ParsedStatement* block, ParsedStatement* nextStatement, unsigned int start, unsigned int length)
+            : ParsedStatement(start, length){
+        _condition = condition;
+        _block = block;
+        _elseStatement = nextStatement;
+    }
+
+    ~ParsedConditionalStatement() final{
+        delete _condition;
+        delete _block;
+        delete _elseStatement;
+    }
+
+    ParsedStatementKind GetKind() final{
+        return ParsedStatementKind ::Conditional;
+    }
+
+    ParsedExpression* GetCondition(){
+        return _condition;
+    }
+
+    ParsedStatement* GetBlock(){
+        return _block;
+    }
+
+    ParsedStatement* GetElseStatement(){
+        return _elseStatement;
+    }
+};
+
 #endif //PORYGONLANG_PARSEDSTATEMENT_HPP

src/Parser/Parser.cpp

@@ -23,6 +23,10 @@ IToken *Parser::Peek() {
     return this -> _tokens[_position];
 }
 
+IToken *Parser::PeekAt(int offset) {
+    return this -> _tokens[_position + offset];
+}
+
 IToken *Parser::Next() {
     this -> _position++;
     return this -> _tokens[_position - 1];
@@ -34,6 +38,7 @@ ParsedStatement* Parser::ParseStatement(IToken* current){
         case TokenKind ::LocalKeyword: return this -> ParseAssignment(current);
         case TokenKind ::FunctionKeyword: return this -> ParseFunctionDeclaration(current);
         case TokenKind ::ReturnKeyword: return this->ParseReturnStatement(current);
+        case TokenKind ::IfKeyword: return this -> ParseIfStatement(current, false);
         default: break;
     }
     if (this->Peek()->GetKind() == TokenKind::AssignmentToken){
@@ -144,6 +149,26 @@ ParsedStatement* Parser::ParseReturnStatement(IToken* current){
     return new ParsedReturnStatement(expression, start, expression->GetEndPosition() - start);
 }
 
+ParsedStatement* Parser::ParseIfStatement(IToken* current, bool isElseIf){
+    auto condition = this->ParseExpression(this->Next());
+    auto next = this -> Next();
+    if (next->GetKind() != TokenKind::ThenKeyword){
+        this -> ScriptData -> Diagnostics -> LogError(DiagnosticCode::UnexpectedToken, next->GetStartPosition(), next->GetLength());
+        return new ParsedBadStatement(next->GetStartPosition(), next->GetLength());
+    }
+    auto block = this -> ParseBlock({TokenKind ::EndKeyword, TokenKind ::ElseKeyword, TokenKind ::ElseIfKeyword});
+    auto closeToken = this->PeekAt(-1);
+    auto start = current->GetStartPosition();
+    if (closeToken->GetKind() == TokenKind::ElseIfKeyword){
+        auto elseIfStatement = this -> ParseIfStatement(closeToken, true);
+        return new ParsedConditionalStatement(condition, block, elseIfStatement, start, elseIfStatement->GetEndPosition() - start);
+    } else if (closeToken->GetKind() == TokenKind::ElseKeyword){
+        auto elseStatement = this -> ParseBlock({TokenKind ::EndKeyword});
+        return new ParsedConditionalStatement(condition, block, elseStatement, start, elseStatement->GetEndPosition() - start);
+    }
+    return new ParsedConditionalStatement(condition, block, start, block->GetEndPosition() - start);
+}
+
 ParsedExpression* Parser::ParseExpression(IToken* current){
     auto expression = this -> ParseBinaryExpression(current, OperatorPrecedence::No);
     auto peekKind = this->Peek()->GetKind();

src/Parser/Parser.hpp

@@ -30,6 +30,7 @@ class Parser {
     ParsedStatement *ParseBlock(const vector<TokenKind>& endTokens);
     ParsedStatement* ParseFunctionDeclaration(IToken* current);
     ParsedStatement *ParseReturnStatement(IToken *current);
+    ParsedStatement *ParseIfStatement(IToken *current, bool isElseIf);
 
     ParsedExpression* ParseExpression(IToken* current);
     ParsedExpression* ParseBinaryExpression(IToken* current, OperatorPrecedence parentPrecedence);
@@ -46,6 +47,8 @@ public:
         ScriptData = scriptData;
     }
 
+
+    IToken *PeekAt(int offset);
 };
 
 

tests/integration/ConditionalTests.cpp

@@ -0,0 +1,43 @@
+#ifdef TESTS_BUILD
+#include <catch.hpp>
+#include "../src/Script.hpp"
+
+TEST_CASE( "Basic conditional", "[integration]" ) {
+    Script* script = Script::Create("if true then foo = true end");
+    REQUIRE(!script->Diagnostics -> HasErrors());
+    auto variable = script->GetVariable("foo");
+    REQUIRE(variable == nullptr);
+    script->Evaluate();
+    variable = script->GetVariable("foo");
+    REQUIRE(variable != nullptr);
+    REQUIRE(variable->EvaluateBool());
+    delete script;
+}
+
+TEST_CASE( "If then, else", "[integration]" ) {
+    Script* script = Script::Create("if false then foo = false else foo = true end");
+    REQUIRE(!script->Diagnostics -> HasErrors());
+    auto variable = script->GetVariable("foo");
+    REQUIRE(variable == nullptr);
+    script->Evaluate();
+    variable = script->GetVariable("foo");
+    REQUIRE(variable != nullptr);
+    REQUIRE(variable->EvaluateBool());
+    delete script;
+}
+
+TEST_CASE( "If then, else if", "[integration]" ) {
+    Script* script = Script::Create("if false then foo = false elseif true then foo = true end");
+    REQUIRE(!script->Diagnostics -> HasErrors());
+    auto variable = script->GetVariable("foo");
+    REQUIRE(variable == nullptr);
+    script->Evaluate();
+    variable = script->GetVariable("foo");
+    REQUIRE(variable != nullptr);
+    REQUIRE(variable->EvaluateBool());
+    delete script;
+}
+
+
+#endif
+