Implements indexing, currently can only be used with strings

src/Binder/Binder.cpp

@@ -128,6 +128,9 @@ BoundExpression* Binder::BindExpression(ParsedExpression* expression){
         case ParsedExpressionKind ::FunctionCall:
             return this->BindFunctionCall((FunctionCallExpression*)expression);
 
+        case ParsedExpressionKind ::Indexer:
+            return this->BindIndexExpression((IndexExpression*)expression);
+
         case ParsedExpressionKind ::Bad:
             return new BoundBadExpression(expression->GetStartPosition(), expression-> GetLength());
     }
@@ -309,3 +312,16 @@ BoundExpression* Binder::BindFunctionCall(FunctionCallExpression* expression){
     return new BoundFunctionCallExpression(functionExpression, boundParameters, functionType.get()->GetReturnType(),
             expression->GetStartPosition(), expression->GetLength());
 }
+
+BoundExpression *Binder::BindIndexExpression(IndexExpression *expression) {
+    auto indexer = this->BindExpression(expression->GetIndexer());
+    auto index = this->BindExpression(expression->GetIndex());
+
+    if (!indexer->GetType()->CanBeIndexedWith(index->GetType().get())){
+        this->_scriptData->Diagnostics->LogError(DiagnosticCode::CantIndex, index->GetStartPosition(),
+                                                 index->GetLength());
+        return new BoundBadExpression(expression->GetStartPosition(), expression->GetLength());
+    }
+    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

@@ -24,6 +24,7 @@ class Binder {
     BoundExpression *BindBinaryOperator(BinaryExpression *expression);
     BoundExpression *BindUnaryOperator(UnaryExpression *expression);
     BoundExpression *BindFunctionCall(FunctionCallExpression *expression);
+    BoundExpression *BindIndexExpression(IndexExpression *expression);
 public:
     static BoundScriptStatement* Bind(Script* script, ParsedScriptStatement* s, BoundScope* scriptScope);
 

src/Binder/BoundExpressions/BoundExpression.hpp

@@ -2,6 +2,8 @@
 
 #include <utility>
 
+#include <utility>
+
 
 #ifndef PORYGONLANG_BOUNDEXPRESSION_HPP
 #define PORYGONLANG_BOUNDEXPRESSION_HPP
@@ -26,6 +28,7 @@ enum class BoundExpressionKind{
     Unary,
     Binary,
     FunctionCall,
+    Index,
 };
 
 class BoundExpression{
@@ -36,7 +39,7 @@ public:
     BoundExpression(unsigned int start, unsigned int length, std::shared_ptr<ScriptType> type){
         _start = start;
         _length = length;
-        _type = type;
+        _type = std::move(type);
     }
     virtual ~BoundExpression() = default;
 
@@ -247,5 +250,31 @@ public:
     }
 };
 
+class BoundIndexExpression : public BoundExpression {
+    BoundExpression* _indexableExpression;
+    BoundExpression* _indexExpression;
+public:
+    BoundIndexExpression(BoundExpression* indexableExpression, BoundExpression* indexExpression, shared_ptr<ScriptType> result,
+                                unsigned int start, unsigned int length)
+            : BoundExpression(start, length, std::move(result)), _indexableExpression(indexableExpression), _indexExpression(indexExpression) {}
+
+    ~BoundIndexExpression() final{
+        delete _indexableExpression;
+        delete _indexExpression;
+    }
+
+    BoundExpressionKind GetKind() final{
+        return BoundExpressionKind ::Index;
+    }
+
+    BoundExpression* GetIndexableExpression(){
+        return _indexableExpression;
+    }
+
+    BoundExpression* GetIndexExpression(){
+        return _indexExpression;
+    }
+};
+
 
 #endif //PORYGONLANG_BOUNDEXPRESSION_HPP

src/Diagnostics/DiagnosticCode.hpp

@@ -18,6 +18,7 @@ enum class DiagnosticCode{
     ExpressionIsNotAFunction,
     ParameterCountMismatch,
     ParameterTypeMismatch,
+    CantIndex,
 };
 
 #endif //PORYGONLANG_DIAGNOSTICCODE_HPP

src/Evaluator/EvalValues/EvalValue.hpp

@@ -34,6 +34,10 @@ public:
     virtual std::string* EvaluateString(){
         throw EvaluationException("Can't evaluate this EvalValue as string.");
     }
+
+    virtual EvalValue* IndexValue(EvalValue* val){
+        throw EvaluationException("Can't index this EvalValue");
+    }
 };
 
 class BooleanEvalValue : public EvalValue{

src/Evaluator/EvalValues/StringEvalValue.hpp

@@ -32,6 +32,12 @@ public:
     shared_ptr<EvalValue> Clone() final{
         return make_shared<StringEvalValue>(_value);
     }
+
+    EvalValue* IndexValue(EvalValue* val) final{
+        // Porygon is 1-indexed, so we convert to that.
+        auto l = val->EvaluateInteger() - 1;
+        return new StringEvalValue(string(1, _value[l]));
+    }
 };
 
 

src/Evaluator/Evaluator.cpp

@@ -89,6 +89,7 @@ shared_ptr<NumericEvalValue> Evaluator::EvaluateIntegerExpression(BoundExpressio
         case BoundExpressionKind ::Binary: return this -> EvaluateIntegerBinary((BoundBinaryExpression*)expression);
         case BoundExpressionKind::Variable: return dynamic_pointer_cast<NumericEvalValue>(this->GetVariable((BoundVariableExpression*)expression));
         case BoundExpressionKind ::FunctionCall: return dynamic_pointer_cast<NumericEvalValue>(this->EvaluateFunctionCallExpression(expression));
+        case BoundExpressionKind ::Index: return dynamic_pointer_cast<NumericEvalValue>(this->EvaluateIndexExpression(expression));
 
         case BoundExpressionKind ::LiteralString:
         case BoundExpressionKind ::LiteralBool:
@@ -104,6 +105,7 @@ shared_ptr<BooleanEvalValue> Evaluator::EvaluateBoolExpression(BoundExpression *
         case BoundExpressionKind::Binary: return this -> EvaluateBooleanBinary((BoundBinaryExpression*)expression);
         case BoundExpressionKind::Variable: return dynamic_pointer_cast<BooleanEvalValue>(this->GetVariable((BoundVariableExpression*)expression));
         case BoundExpressionKind ::FunctionCall: return dynamic_pointer_cast<BooleanEvalValue>(this->EvaluateFunctionCallExpression(expression));
+        case BoundExpressionKind ::Index: return dynamic_pointer_cast<BooleanEvalValue>(this->EvaluateIndexExpression(expression));
 
         case BoundExpressionKind::Bad:
         case BoundExpressionKind::LiteralInteger:
@@ -122,6 +124,7 @@ shared_ptr<StringEvalValue> Evaluator::EvaluateStringExpression(BoundExpression
             return this -> EvaluateStringBinary((BoundBinaryExpression*)expression);
         case BoundExpressionKind::Variable: return dynamic_pointer_cast<StringEvalValue>(this->GetVariable((BoundVariableExpression*)expression));
         case BoundExpressionKind ::FunctionCall: return dynamic_pointer_cast<StringEvalValue>(this->EvaluateFunctionCallExpression(expression));
+        case BoundExpressionKind ::Index: return dynamic_pointer_cast<StringEvalValue>(this->EvaluateIndexExpression(expression));
 
         case BoundExpressionKind::Bad:
         case BoundExpressionKind::LiteralInteger:
@@ -191,3 +194,10 @@ EvalValue* Evaluator::EvaluateFunction(ScriptFunctionEvalValue *function, vector
     this->EvaluateBlockStatement(function->GetInnerBlock().get());
     return nullptr;
 }
+
+shared_ptr<EvalValue> Evaluator::EvaluateIndexExpression(BoundExpression *expression) {
+    auto indexExpression = (BoundIndexExpression*)expression;
+    auto index = this -> EvaluateExpression(indexExpression->GetIndexExpression());
+    auto indexable = this -> EvaluateExpression(indexExpression->GetIndexableExpression());
+    return shared_ptr<EvalValue>(indexable -> IndexValue(index.get()));
+}

src/Evaluator/Evaluator.hpp

@@ -41,6 +41,7 @@ class Evaluator {
     shared_ptr<NumericEvalValue> EvaluateIntegerUnary(BoundUnaryExpression* expression);
     shared_ptr<BooleanEvalValue> EvaluateBooleanUnary(BoundUnaryExpression *expression);
     shared_ptr<EvalValue> EvaluateFunctionCallExpression(BoundExpression *expression);
+    shared_ptr<EvalValue> EvaluateIndexExpression(BoundExpression* expression);
 
     shared_ptr<EvalValue> GetVariable(BoundVariableExpression *expression);
 public:
@@ -56,10 +57,6 @@ public:
     void Evaluate(BoundScriptStatement* statement);
     EvalValue* EvaluateFunction(ScriptFunctionEvalValue* func, vector<EvalValue*> parameters);
 
-    EvaluationScope* GetScope(){
-        return _evaluationScope;
-    }
-
     EvalValue* GetLastValue(){
         return _lastValue.get();
     }

src/Evaluator/UnaryEvaluation.cpp

@@ -34,4 +34,3 @@ shared_ptr<BooleanEvalValue> Evaluator::EvaluateBooleanUnary(BoundUnaryExpressio
             throw;
     }
 }
-

src/Parser/ParsedExpressions/ParsedExpression.hpp

@@ -22,6 +22,7 @@ enum class ParsedExpressionKind{
     Binary,
     Parenthesized,
     FunctionCall,
+    Indexer,
 };
 
 class ParsedExpression {
@@ -246,5 +247,28 @@ public:
     }
 };
 
+class IndexExpression : public ParsedExpression{
+    std::unique_ptr<ParsedExpression> _indexerExpression;
+    std::unique_ptr<ParsedExpression> _indexExpression;
+public:
+    IndexExpression(ParsedExpression* indexer, ParsedExpression* index, unsigned int start, unsigned int length)
+    :ParsedExpression(start, length){
+        _indexerExpression = std::unique_ptr<ParsedExpression>(indexer);
+        _indexExpression = std::unique_ptr<ParsedExpression>(index);
+    }
+
+    ParsedExpressionKind GetKind() final{
+        return ParsedExpressionKind::Indexer;
+    }
+
+    ParsedExpression* GetIndexer(){
+        return _indexerExpression.get();
+    }
+
+    ParsedExpression* GetIndex(){
+        return _indexExpression.get();
+    }
+};
+
 
 #endif //PORYGONLANG_PARSEDEXPRESSION_HPP

src/Parser/Parser.cpp

@@ -146,10 +146,11 @@ ParsedExpression* Parser::ParseExpression(IToken* current){
         if (peekKind == TokenKind::OpenParenthesis){
             expression = this->ParseFunctionCallExpression(expression);
         } else if (peekKind == TokenKind::OpenSquareBracket){
-            //TODO: index expression
+            expression = this->ParseIndexExpression(expression);
         } else {
             //TODO: index period expression
         }
+        peekKind = this->Peek()->GetKind();
     }
     return expression;
 }
@@ -283,7 +284,17 @@ ParsedExpression *Parser::ParseFunctionCallExpression(ParsedExpression* function
     return new FunctionCallExpression(functionExpression, parameters, start, peeked->GetEndPosition() - start);
 }
 
-
+ParsedExpression* Parser::ParseIndexExpression(ParsedExpression* indexingExpression){
+    this->Next(); // consume '[' token
+    auto indexExpression = this -> ParseExpression(this -> Next());
+    auto closeBracket = this->Next();
+    if (closeBracket->GetKind() != TokenKind::CloseSquareBracket){
+        this->ScriptData->Diagnostics->LogError(DiagnosticCode::UnexpectedToken, closeBracket->GetStartPosition(), closeBracket->GetLength());
+        return new BadExpression(closeBracket->GetStartPosition(), closeBracket->GetLength());
+    }
+    auto start = indexingExpression->GetStartPosition();
+    return new IndexExpression(indexingExpression, indexExpression, start, closeBracket->GetEndPosition() - start);
+}
 
 
 

src/Parser/Parser.hpp

@@ -34,7 +34,9 @@ class Parser {
     ParsedExpression* ParseBinaryExpression(IToken* current, OperatorPrecedence parentPrecedence);
     ParsedExpression* ParsePrimaryExpression(IToken* current);
     ParsedExpression* ParseParenthesizedExpression(IToken *current);
+
     ParsedExpression* ParseFunctionCallExpression(ParsedExpression* functionExpression);
+    ParsedExpression *ParseIndexExpression(ParsedExpression *indexingExpression);
 public:
     ParsedScriptStatement* Parse();
     explicit Parser(vector<IToken*> tokens, Script* scriptData){

src/ScriptType.cpp

@@ -0,0 +1,13 @@
+#include "Script.hpp"
+
+bool ScriptType::CanBeIndexedWith(ScriptType *indexer) {
+    // String type is the only simple script type we want to
+    return _class == TypeClass::String && indexer->_class == TypeClass::Number && !((NumericScriptType*)indexer)->IsFloat();
+}
+
+ScriptType *ScriptType::GetIndexedType(ScriptType *indexer) {
+    if (_class == TypeClass::String){
+        return new ScriptType(TypeClass::String);
+    }
+    return new ScriptType(TypeClass::Error);
+}

src/ScriptType.hpp

@@ -52,6 +52,10 @@ public:
     virtual bool operator !=(ScriptType* b){
         return ! (operator==(b));
     }
+
+    virtual bool CanBeIndexedWith(ScriptType* indexer);
+
+    virtual ScriptType* GetIndexedType(ScriptType* indexer);
 };
 
 class NumericScriptType : public ScriptType{

tests/integration/IndexTests.cpp

@@ -0,0 +1,14 @@
+#ifdef TESTS_BUILD
+#include <catch.hpp>
+#include "../src/Script.hpp"
+
+TEST_CASE( "String indexing", "[integration]" ) {
+    auto script = Script::Create("'foobar'[4]");
+    REQUIRE(!script->Diagnostics -> HasErrors());
+    script->Evaluate();
+    auto lastValue = script->GetLastValue();
+    REQUIRE(*lastValue->EvaluateString() == "b");
+    delete script;
+}
+
+#endif