Started implementing parser

parser/inc/Parser.h

@@ -15,7 +15,7 @@ namespace LXC::Parser
             name{}, contents{}
         {}
 
-        FunctionAST(FunctionAST&& other) :
+        FunctionAST(FunctionAST&& other) noexcept :
             name{}, contents{}
         {}
 

parser/src/Parser.cpp

@@ -23,8 +23,11 @@ namespace LXC::Parser
                 return &input[peekIndex];
             }
 
+            // Returns a pointer to the current token //
+            inline const Lexer::Token* At() const { return Peek(0); }
+
             // Advances x-distance in the tokens (default 1) //
-            inline const Lexer::Token* Next(size_t distance = 1)
+            inline const Lexer::Token* Advance(size_t distance = 1)
             {
                 // Adds the distance and checks if in bounds to stop read errors //
                 index += distance;
@@ -34,6 +37,19 @@ namespace LXC::Parser
                 return &input[index];
             }
 
+            // Checks if the tokens are the correct types //
+            inline bool Expect(const std::span<const Lexer::Token::TokenType>& tokens) const
+            {
+                for (int i = 0; i < tokens.size(); i++)
+                {
+                    const Lexer::Token* current = Peek(i);
+                    if (!current || current->type != tokens[i])
+                        return false;
+                }
+
+                return true;
+            }
+
             // Is the current index in bounds //
             inline bool InBounds() const { return index < length; }
 
@@ -47,9 +63,90 @@ namespace LXC::Parser
             const size_t length;
     };
 
-    static Util::ReturnVal<void*, ParserError> ParseFunction(const ParserContext& ctx)
+    static void ParseBlock(ParserContext& ctx)
     {
-        return Util::FunctionFail<ParserError>();
+        // Local lamdba for working out if at the end (static to avoid double initalisation) //
+        static const std::function<bool(const ParserContext&)> AtEnd = [](const ParserContext& context)
+        {
+            // Peeks the current tokens type //
+            const Lexer::Token* current = context.Peek();
+            if (current != nullptr)
+            {
+                return current->type == Lexer::Token::CloseBrace;
+            }
+
+            // If nullptr means it has overflowed so it is at the end //
+            return true;
+        };
+
+        // Loops over the body until it reaches the end //
+        while (!AtEnd(ctx))
+        {
+            // Force ends if it has gone over the end of the tokens //
+            const Lexer::Token* current = ctx.Advance();
+            if (current != nullptr)
+            {
+                // Recurses if at the start of another block //
+                if (current->type == Lexer::Token::OpenBrace)
+                    ParseBlock(ctx);
+            }
+        }
+
+        // Advances over the ending close brace //
+        ctx.Advance();
+    }
+
+    static Util::ReturnVal<FunctionAST, ParserError> ParseFunction(ParserContext& ctx)
+    {   
+        // Checks for the sequence of: func<T> funcName( //
+        if (!ctx.Expect(std::array{ Lexer::Token::FunctionDef, Lexer::Token::OpenCrocodile, Lexer::Token::Identifier, Lexer::Token::CloseCrocodile, Lexer::Token::Identifier, Lexer::Token::OpenParen }))
+            return Util::FunctionFail<ParserError>(); // <- TODO: Make an actual error
+
+        // Assumes int for now so skips over func<T> //
+        const Lexer::Token* funcName = ctx.Advance(4);
+        
+        // Assigns the name of the function //
+        FunctionAST currentFunction;
+        currentFunction.name = funcName->Str();
+
+        // Looks for the parameters of the function //
+        const Lexer::Token* paramsStart = ctx.Advance(2);
+        if (paramsStart == nullptr )
+            return Util::FunctionFail<ParserError>(); // <- TODO: Make an actual error
+
+        // Parses the parameters of the function //
+        if (paramsStart->type == Lexer::Token::Identifier && paramsStart->Str() == "void")
+        { /* No parameters/arguments for the function */}
+
+        // Loops over the parameters/arguments of the function declaration //
+        else
+        {
+            while (ctx.At()->type != Lexer::Token::CloseParen)
+            {
+                // Checks for parameter pattern: identifier, identifier //
+                if (!ctx.Expect(std::array{ Lexer::Token::Identifier, Lexer::Token::Identifier }))
+                    return Util::FunctionFail<ParserError>(); // <- TODO: Make an actual error
+
+                const Lexer::Token* paramType = ctx.At();
+                const Lexer::Token* paramName = ctx.Advance();
+
+                // Expects a comma or close bracket for the next token //
+                const Lexer::Token* end = ctx.Advance();
+                if (end == nullptr)
+                    return Util::FunctionFail<ParserError>(); // <- TODO: Make an actual error
+
+                if (end->type == Lexer::Token::Comma || end->type == Lexer::Token::CloseParen)
+                    continue;
+
+                return Util::FunctionFail<ParserError>(); // <- TODO: Make an actual error
+            }
+        }
+
+        // Parses the function body //
+        ParseBlock(ctx);
+        ctx.Advance(); // <- Goes over the closing brace
+        
+        return currentFunction;
     }
 
     Util::ReturnVal<std::vector<FunctionAST>, ParserError> TurnTokensIntoAST(const Lexer::LexerOutput& input)
@@ -58,10 +155,10 @@ namespace LXC::Parser
         ParserContext ctx(input);
 
         // Continues whilst in the bounds of the tokens //
-        while (ctx.InBounds())
+         while (ctx.InBounds())
         {
             // Peeks the next token (guaranteed to not be at the end) //
-            const Lexer::Token* current = ctx.Peek();
+            const Lexer::Token* current = ctx.At();
 
             // Switches over the type of the current token to run the correct logic //
             switch (current->type)
@@ -84,6 +181,6 @@ namespace LXC::Parser
         }
 
         // Returns the output as it has gone through all the tokens //
-        return std::move(ctx.output); // Moves instead of copying, (required due to std::unique_ptr<>)
+        return std::move(ctx.output); // Moves instead of copying, (required due to std::unique_ptr<> within the class)
     }
 }