]> git.tdb.fi Git - libs/gl.git/commitdiff
Implement an actual expression parser
authorMikko Rasa <tdb@tdb.fi>
Tue, 8 Nov 2016 20:36:07 +0000 (22:36 +0200)
committerMikko Rasa <tdb@tdb.fi>
Tue, 8 Nov 2016 20:57:54 +0000 (22:57 +0200)
Doing pretty much anything interesting with the syntax tree requires
having access to expressions.

source/programcompiler.cpp
source/programcompiler.h
source/programparser.cpp
source/programparser.h
source/programsyntax.cpp
source/programsyntax.h

index b08f1737e4d542610d1a9401f37ac3df90e580cd..1914831289a9dde32c77892cb3bfdc5411fd4900 100644 (file)
@@ -59,14 +59,65 @@ ProgramCompiler::Formatter::Formatter():
        else_if(false)
 { }
 
-string ProgramCompiler::Formatter::format_expression(Expression &expr)
+void ProgramCompiler::Formatter::visit(Literal &literal)
 {
-       return join(expr.tokens.begin(), expr.tokens.end(), string());
+       formatted += literal.token;
+}
+
+void ProgramCompiler::Formatter::visit(ParenthesizedExpression &parexpr)
+{
+       formatted += '(';
+       parexpr.expression->visit(*this);
+       formatted += ')';
+}
+
+void ProgramCompiler::Formatter::visit(VariableReference &var)
+{
+       formatted += var.name;
+}
+
+void ProgramCompiler::Formatter::visit(MemberAccess &memacc)
+{
+       memacc.left->visit(*this);
+       formatted += format(".%s", memacc.member);
+}
+
+void ProgramCompiler::Formatter::visit(UnaryExpression &unary)
+{
+       if(unary.prefix)
+               formatted += unary.oper;
+       unary.expression->visit(*this);
+       if(!unary.prefix)
+               formatted += unary.oper;
+}
+
+void ProgramCompiler::Formatter::visit(BinaryExpression &binary)
+{
+       binary.left->visit(*this);
+       if(binary.assignment)
+               formatted += format(" %s ", binary.oper);
+       else
+               formatted += binary.oper;
+       binary.right->visit(*this);
+       formatted += binary.after;
+}
+
+void ProgramCompiler::Formatter::visit(FunctionCall &call)
+{
+       formatted += format("%s(", call.name);
+       for(vector<NodePtr<Expression> >::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
+       {
+               if(i!=call.arguments.begin())
+                       formatted += ", ";
+               (*i)->visit(*this);
+       }
+       formatted += ')';
 }
 
 void ProgramCompiler::Formatter::visit(ExpressionStatement &expr)
 {
-       formatted += format("%s;", format_expression(expr.expression));
+       expr.expression->visit(*this);
+       formatted += ';';
 }
 
 void ProgramCompiler::Formatter::visit(Block &block)
@@ -84,7 +135,7 @@ void ProgramCompiler::Formatter::visit(Block &block)
        bool change_indent = (!formatted.empty() && !else_if);
        indent += change_indent;
        string spaces(indent*2, ' ');
-       for(vector<Node *>::const_iterator i=block.body.begin(); i!=block.body.end(); ++i)
+       for(vector<NodePtr<Node> >::iterator i=block.body.begin(); i!=block.body.end(); ++i)
        {
                if(i!=block.body.begin())
                        formatted += '\n';
@@ -129,9 +180,17 @@ void ProgramCompiler::Formatter::visit(VariableDeclaration &var)
                formatted += format("%s ", var.interface);
        formatted += format("%s %s", var.type, var.name);
        if(var.array)
-               formatted += format("[%s]", format_expression(var.array_size));
-       if(!var.init_expression.empty())
-               formatted += format(" = %s", format_expression(var.init_expression));
+       {
+               formatted += '[';
+               if(var.array_size)
+                       var.array_size->visit(*this);
+               formatted += ']';
+       }
+       if(var.init_expression)
+       {
+               formatted += " = ";
+               var.init_expression->visit(*this);
+       }
        if(!parameter_list)
                formatted += ';';
 }
@@ -147,7 +206,7 @@ void ProgramCompiler::Formatter::visit(FunctionDeclaration &func)
 {
        formatted += format("%s %s(", func.return_type, func.name);
        parameter_list = true;
-       for(vector<VariableDeclaration *>::const_iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
+       for(vector<NodePtr<VariableDeclaration> >::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
        {
                if(i!=func.parameters.begin())
                        formatted += ", ";
@@ -171,7 +230,11 @@ void ProgramCompiler::Formatter::visit(Conditional &cond)
                formatted += ' ';
                else_if = false;
        }
-       formatted += format("if(%s)\n", format_expression(cond.condition));
+
+       formatted += "if(";
+       cond.condition->visit(*this);
+       formatted += ")\n";
+
        cond.body.visit(*this);
        if(!cond.else_body.body.empty())
        {
@@ -186,13 +249,19 @@ void ProgramCompiler::Formatter::visit(Iteration &iter)
 {
        formatted += "for(";
        iter.init_statement->visit(*this);
-       formatted += format(" %s; %s)\n", format_expression(iter.condition), format_expression(iter.loop_expression));
+       formatted += ' ';
+       iter.condition->visit(*this);
+       formatted += "; ";
+       iter.loop_expression->visit(*this);
+       formatted += ")\n";
        iter.body.visit(*this);
 }
 
 void ProgramCompiler::Formatter::visit(Return &ret)
 {
-       formatted += format("return %s;", format_expression(ret.expression));
+       formatted += "return ";
+       ret.expression->visit(*this);
+       formatted += ';';
 }
 
 } // namespace GL
index 9a825489df87e27178cfc0b0e775de0ff6b9ebbc..1959618f30509ec76882c4a427745df83dcc7e25 100644 (file)
@@ -21,8 +21,14 @@ public:
 
                Formatter();
 
-               std::string format_expression(ProgramSyntax::Expression &);
                virtual void visit(ProgramSyntax::Block &);
+               virtual void visit(ProgramSyntax::Literal &);
+               virtual void visit(ProgramSyntax::ParenthesizedExpression &);
+               virtual void visit(ProgramSyntax::VariableReference &);
+               virtual void visit(ProgramSyntax::MemberAccess &);
+               virtual void visit(ProgramSyntax::UnaryExpression &);
+               virtual void visit(ProgramSyntax::BinaryExpression &);
+               virtual void visit(ProgramSyntax::FunctionCall &);
                virtual void visit(ProgramSyntax::ExpressionStatement &);
                virtual void visit(ProgramSyntax::Layout &);
                virtual void visit(ProgramSyntax::StructDeclaration &);
index 1981f474eb679794fc66b495666f621d93ad2c57..bf2d42daedbfd232dcc0dd194deb7c60ddf76625 100644 (file)
@@ -9,6 +9,55 @@ namespace GL {
 
 using namespace ProgramSyntax;
 
+ProgramParser::Operator ProgramParser::operators[] =
+{
+       { "[", 2, BINARY, LEFT_TO_RIGHT },
+       { "(", 2, BINARY, LEFT_TO_RIGHT },
+       { ".", 2, BINARY, LEFT_TO_RIGHT },
+       { "++", 2, POSTFIX, LEFT_TO_RIGHT },
+       { "--", 2, POSTFIX, LEFT_TO_RIGHT },
+       { "++", 3, PREFIX, RIGHT_TO_LEFT },
+       { "--", 3, PREFIX, RIGHT_TO_LEFT },
+       { "+", 3, PREFIX, RIGHT_TO_LEFT },
+       { "-", 3, PREFIX, RIGHT_TO_LEFT },
+       { "~", 3, PREFIX, RIGHT_TO_LEFT },
+       { "!", 3, PREFIX, RIGHT_TO_LEFT },
+       { "*", 4, BINARY, LEFT_TO_RIGHT },
+       { "/", 4, BINARY, LEFT_TO_RIGHT },
+       { "%", 4, BINARY, LEFT_TO_RIGHT },
+       { "+", 5, BINARY, LEFT_TO_RIGHT },
+       { "-", 5, BINARY, LEFT_TO_RIGHT },
+       { "<<", 6, BINARY, LEFT_TO_RIGHT },
+       { ">>", 6, BINARY, LEFT_TO_RIGHT },
+       { "<", 7, BINARY, LEFT_TO_RIGHT },
+       { ">", 7, BINARY, LEFT_TO_RIGHT },
+       { "<=", 7, BINARY, LEFT_TO_RIGHT },
+       { ">=", 7, BINARY, LEFT_TO_RIGHT },
+       { "==", 8, BINARY, LEFT_TO_RIGHT },
+       { "!=", 8, BINARY, LEFT_TO_RIGHT },
+       { "&", 9, BINARY, LEFT_TO_RIGHT },
+       { "^", 10, BINARY, LEFT_TO_RIGHT },
+       { "|", 11, BINARY, LEFT_TO_RIGHT },
+       { "&&", 12, BINARY, LEFT_TO_RIGHT },
+       { "^^", 13, BINARY, LEFT_TO_RIGHT },
+       { "||", 14, BINARY, LEFT_TO_RIGHT },
+       { "?", 15, BINARY, RIGHT_TO_LEFT },
+       { ":", 15, BINARY, RIGHT_TO_LEFT },
+       { "=", 16, BINARY, RIGHT_TO_LEFT },
+       { "+=", 16, BINARY, RIGHT_TO_LEFT },
+       { "-=", 16, BINARY, RIGHT_TO_LEFT },
+       { "*=", 16, BINARY, RIGHT_TO_LEFT },
+       { "/=", 16, BINARY, RIGHT_TO_LEFT },
+       { "%=", 16, BINARY, RIGHT_TO_LEFT },
+       { "<<=", 16, BINARY, RIGHT_TO_LEFT },
+       { ">>=", 16, BINARY, RIGHT_TO_LEFT },
+       { "&=", 16, BINARY, RIGHT_TO_LEFT },
+       { "^=", 16, BINARY, RIGHT_TO_LEFT },
+       { "|=", 16, BINARY, RIGHT_TO_LEFT },
+       { ",", 17, BINARY, LEFT_TO_RIGHT },
+       { { 0 }, 18, NO_OPERATOR, LEFT_TO_RIGHT }
+};
+
 Module &ProgramParser::parse(const string &s)
 {
        source = s;
@@ -129,14 +178,24 @@ string ProgramParser::parse_number()
 
 string ProgramParser::parse_other()
 {
-       string token;
-       while(iter!=source.end())
+       if(iter==source.end())
+               return string();
+
+       string token(1, *iter++);
+       for(unsigned i=1; (i<3 && iter!=source.end()); ++i)
        {
-               if(isalnum(*iter) || *iter=='_' || isspace(*iter))
+               bool matched = false;
+               for(const Operator *j=operators; (!matched && j->type); ++j)
+               {
+                       matched = (j->token[i]==*iter);
+                       for(unsigned k=0; (matched && k<i && j->token[k]); ++k)
+                               matched = (j->token[k]==token[k]);
+               }
+
+               if(!matched)
                        break;
+
                token += *iter++;
-               if(*iter==';' || *iter=='(' || *iter==')' || *iter=='[' || *iter==']')
-                       break;
        }
 
        return token;
@@ -214,9 +273,8 @@ string ProgramParser::expect_type()
 
 string ProgramParser::expect_identifier()
 {
-       static Regex re("^[a-zA-Z_][a-zA-Z0-9_]*$");
        string token = parse_token();
-       if(!re.match(token))
+       if(!is_identifier(token))
                throw runtime_error(format("Parse error at '%s': expected an identifier", token));
        return token;
 }
@@ -255,6 +313,12 @@ bool ProgramParser::is_type(const string &token)
        return is_builtin_type(token) || cur_module->structs.count(token);
 }
 
+bool ProgramParser::is_identifier(const string &token)
+{
+       static Regex re("^[a-zA-Z_][a-zA-Z0-9_]*$");
+       return re.match(token);
+}
+
 Node *ProgramParser::parse_global_declaration()
 {
        string token = peek_token();
@@ -298,7 +362,7 @@ Node *ProgramParser::parse_statement()
        else if(!token.empty())
        {
                RefPtr<ExpressionStatement> expr = new ExpressionStatement;
-               parse_expression(expr->expression);
+               expr->expression = parse_expression();
                expect(";");
 
                return expr.release();
@@ -343,16 +407,13 @@ void ProgramParser::parse_block(Block &block, bool require_braces)
        if(have_braces)
                expect("{");
 
-       while(1)
+       if(have_braces)
        {
-               string token = peek_token();
-               if(token=="}")
-                       break;
-
-               block.body.push_back(parse_statement());
-               if(!have_braces)
-                       break;
+               while(peek_token()!="}")
+                       block.body.push_back(parse_statement());
        }
+       else
+               block.body.push_back(parse_statement());
 
        block.use_braces = (require_braces || block.body.size()!=1);
 
@@ -360,26 +421,124 @@ void ProgramParser::parse_block(Block &block, bool require_braces)
                expect("}");
 }
 
-void ProgramParser::parse_expression(Expression &expr)
+Expression *ProgramParser::parse_expression(unsigned precedence)
 {
-       unsigned nesting_level = 0;
-       while(iter!=source.end())
+       RefPtr<Expression> left;
+       VariableReference *left_var = 0;
+       while(1)
        {
                string token = peek_token();
-               if(token=="(" || token=="[")
-                       ++nesting_level;
-               else if(token==")" || token=="]")
+
+               const Operator *oper = 0;
+               for(Operator *i=operators; (!oper && i->type); ++i)
+                       if(token==i->token && (!left || i->type!=PREFIX) && (left || i->type!=POSTFIX))
+                               oper = i;
+
+               if(token==";" || token==")" || token=="]" || token=="," || (oper && precedence && oper->precedence>=precedence))
                {
-                       if(!nesting_level)
-                               break;
-                       --nesting_level;
+                       if(left)
+                               return left.release();
+                       else
+                               throw runtime_error(format("Parse error at '%s': expected an expression", token));
                }
-               else if(token==";")
-                       break;
+               else if(left)
+               {
+                       if(token=="(")
+                       {
+                               if(!left_var)
+                                       throw runtime_error(format("Parse error at '%s': function name must be an identifier", token));
+                               left = parse_function_call(left_var);
+                       }
+                       else if(token==".")
+                       {
+                               RefPtr<MemberAccess> memacc = new MemberAccess;
+                               memacc->left = left.release();
+                               parse_token();
+                               memacc->member = expect_identifier();
+                               left = memacc;
+                       }
+                       else if(oper && oper->type==POSTFIX)
+                       {
+                               RefPtr<UnaryExpression> unary = new UnaryExpression;
+                               unary->oper = parse_token();
+                               unary->prefix = false;
+                               unary->expression = left.release();
+                               left = unary;
+                       }
+                       else if(oper && oper->type==BINARY)
+                               left = parse_binary(left.release(), oper);
+                       else
+                               throw runtime_error(format("Parse error at '%s': expected an operator", token));
+                       left_var = 0;
+               }
+               else
+               {
+                       if(token=="(")
+                       {
+                               parse_token();
+                               RefPtr<ParenthesizedExpression> parexpr = new ParenthesizedExpression;
+                               parexpr->expression = parse_expression();
+                               expect(")");
+                               left = parexpr;
+                       }
+                       else if(is_identifier(token))
+                       {
+                               RefPtr<VariableReference> var = new VariableReference;
+                               var->name = expect_identifier();
+                               left = var;
+                               left_var = var.get();
+                       }
+                       else if(oper && oper->type==PREFIX)
+                       {
+                               RefPtr<UnaryExpression> unary = new UnaryExpression;
+                               unary->oper = parse_token();
+                               unary->prefix = true;
+                               unary->expression = parse_expression(oper->precedence);
+                               left = unary;
+                       }
+                       else if(isdigit(token[0]))
+                       {
+                               RefPtr<Literal> literal = new Literal;
+                               literal->token = parse_token();
+                               left = literal;
+                       }
+                       else
+                               throw runtime_error(format("Parse error at '%s': expected an expression", token));
+               }
+       }
+}
 
-               parse_token();
-               expr.tokens.push_back(token);
+BinaryExpression *ProgramParser::parse_binary(Expression *left, const Operator *oper)
+{
+       RefPtr<BinaryExpression> binary = new BinaryExpression;
+       binary->left = left;
+       binary->oper = parse_token();
+       if(binary->oper=="[")
+       {
+               binary->right = parse_expression();
+               expect("]");
+               binary->after = "]";
        }
+       else
+               binary->right = parse_expression(oper->precedence+(oper->assoc==RIGHT_TO_LEFT));
+       binary->assignment = (oper->precedence==16);
+       return binary.release();
+}
+
+FunctionCall *ProgramParser::parse_function_call(VariableReference *var)
+{
+       RefPtr<FunctionCall> call = new FunctionCall;
+       call->name = var->name;
+       call->constructor = is_type(call->name);
+       expect("(");
+       while(peek_token()!=")")
+       {
+               if(!call->arguments.empty())
+                       expect(",");
+               call->arguments.push_back(parse_expression());
+       }
+       expect(")");
+       return call.release();
 }
 
 StructDeclaration *ProgramParser::parse_struct_declaration()
@@ -424,13 +583,13 @@ VariableDeclaration *ProgramParser::parse_variable_declaration()
                var->array = true;
                if(!check("]"))
                {
-                       parse_expression(var->array_size);
+                       var->array_size = parse_expression();
                        expect("]");
                }
        }
 
        if(check("="))
-               parse_expression(var->init_expression);
+               var->init_expression = parse_expression();
 
        expect(";");
        return var.release();
@@ -461,12 +620,9 @@ FunctionDeclaration *ProgramParser::parse_function_declaration()
 void ProgramParser::parse_function_parameter_list(FunctionDeclaration &func)
 {
        expect("(");
-       while(1)
+       while(peek_token()!=")")
        {
-               string token = peek_token();
-               if(token==")")
-                       break;
-               else if(!func.parameters.empty())
+               if(!func.parameters.empty())
                        expect(",");
 
                RefPtr<VariableDeclaration> var = new VariableDeclaration;
@@ -497,7 +653,7 @@ Conditional *ProgramParser::parse_conditional()
        expect("if");
        expect("(");
        RefPtr<Conditional> cond = new Conditional;
-       parse_expression(cond->condition);
+       cond->condition = parse_expression();
        expect(")");
 
        parse_block(cond->body, false);
@@ -523,13 +679,13 @@ Iteration *ProgramParser::parse_iteration()
        else
        {
                RefPtr<ExpressionStatement> expr = new ExpressionStatement;
-               parse_expression(expr->expression);
+               expr->expression = parse_expression();
                expect(";");
                loop->init_statement = expr.release();
        }
-       parse_expression(loop->condition);
+       loop->condition = parse_expression();
        expect(";");
-       parse_expression(loop->loop_expression);
+       loop->loop_expression = parse_expression();
        expect(")");
 
        parse_block(loop->body, false);
@@ -541,7 +697,7 @@ Return *ProgramParser::parse_return()
 {
        expect("return");
        RefPtr<Return> ret = new Return;
-       parse_expression(ret->expression);
+       ret->expression = parse_expression();
        expect(";");
        return ret.release();
 }
index 0a91c500b1a24884401614d7188953a77ae809a8..4bd6b70e99e1b9e2064eb9de9416a253ae5286bc 100644 (file)
@@ -13,12 +13,36 @@ namespace GL {
 class ProgramParser
 {
 private:
+       enum OperatorType
+       {
+               NO_OPERATOR,
+               BINARY,
+               PREFIX,
+               POSTFIX
+       };
+
+       enum Associativity
+       {
+               LEFT_TO_RIGHT,
+               RIGHT_TO_LEFT
+       };
+
+       struct Operator
+       {
+               const char token[4];
+               unsigned precedence;
+               OperatorType type;
+               Associativity assoc;
+       };
+
        std::string source;
        std::string::const_iterator iter;
        std::deque<std::string> next_tokens;
        ProgramSyntax::Module main_module;
        ProgramSyntax::Module *cur_module;
 
+       static Operator operators[];
+
 public:
        ProgramSyntax::Module &parse(const std::string &);
        ProgramSyntax::Module &parse(IO::Base &);
@@ -43,12 +67,15 @@ private:
        static bool is_qualifier(const std::string &);
        static bool is_builtin_type(const std::string &);
        bool is_type(const std::string &);
+       bool is_identifier(const std::string &);
 
        ProgramSyntax::Node *parse_global_declaration();
        ProgramSyntax::Node *parse_statement();
        ProgramSyntax::Layout *parse_layout();
        void parse_block(ProgramSyntax::Block &, bool);
-       void parse_expression(ProgramSyntax::Expression &);
+       ProgramSyntax::Expression *parse_expression(unsigned = 0);
+       ProgramSyntax::BinaryExpression *parse_binary(ProgramSyntax::Expression *, const Operator *);
+       ProgramSyntax::FunctionCall *parse_function_call(ProgramSyntax::VariableReference *);
        ProgramSyntax::StructDeclaration *parse_struct_declaration();
        ProgramSyntax::VariableDeclaration *parse_variable_declaration();
        ProgramSyntax::FunctionDeclaration *parse_function_declaration();
index 09ba82c31fddd42bd10ab2d524ae8f9154e37035..5b39d7f3036a4f90e9f495f9ff2f172e02cc59e2 100644 (file)
@@ -10,13 +10,61 @@ Block::Block():
        use_braces(false)
 { }
 
-Block::~Block()
+void Block::visit(NodeVisitor &visitor)
 {
-       for(vector<Node *>::iterator i=body.begin(); i!=body.end(); ++i)
-               delete *i;
+       visitor.visit(*this);
 }
 
-void Block::visit(NodeVisitor &visitor)
+
+void Literal::visit(NodeVisitor &visitor)
+{
+       visitor.visit(*this);
+}
+
+
+void ParenthesizedExpression::visit(NodeVisitor &visitor)
+{
+       visitor.visit(*this);
+}
+
+
+void VariableReference::visit(NodeVisitor &visitor)
+{
+       visitor.visit(*this);
+}
+
+
+void MemberAccess::visit(NodeVisitor &visitor)
+{
+       visitor.visit(*this);
+}
+
+
+UnaryExpression::UnaryExpression():
+       prefix(true)
+{ }
+
+void UnaryExpression::visit(NodeVisitor &visitor)
+{
+       visitor.visit(*this);
+}
+
+
+BinaryExpression::BinaryExpression():
+       assignment(false)
+{ }
+
+void BinaryExpression::visit(NodeVisitor &visitor)
+{
+       visitor.visit(*this);
+}
+
+
+FunctionCall::FunctionCall():
+       constructor(false)
+{ }
+
+void FunctionCall::visit(NodeVisitor &visitor)
 {
        visitor.visit(*this);
 }
@@ -71,12 +119,6 @@ FunctionDeclaration::FunctionDeclaration():
        definition(false)
 { }
 
-FunctionDeclaration::~FunctionDeclaration()
-{
-       for(vector<VariableDeclaration *>::iterator i=parameters.begin(); i!=parameters.end(); ++i)
-               delete *i;
-}
-
 void FunctionDeclaration::visit(NodeVisitor &visitor)
 {
        visitor.visit(*this);
@@ -95,15 +137,6 @@ void Return::visit(NodeVisitor &visitor)
 }
 
 
-Iteration::Iteration():
-       init_statement(0)
-{ }
-
-Iteration::~Iteration()
-{
-       delete init_statement;
-}
-
 void Iteration::visit(NodeVisitor &visitor)
 {
        visitor.visit(*this);
index 0013d82a97a7cd8c890e3f0a4456ae5dd4875400..99ce8b9c1c47ebd20c202042d35218e67cfe17a8 100644 (file)
@@ -13,33 +13,130 @@ struct NodeVisitor;
 
 struct Node
 {
+private:
+       Node &operator=(const Node &);
+public:
        virtual ~Node() { }
 
+       virtual Node *clone() const = 0;
        virtual void visit(NodeVisitor &) = 0;
 };
 
+template<typename T>
+class NodePtr
+{
+private:
+       T *node;
+
+public:
+       NodePtr(T *n = 0): node(n) { }
+       NodePtr(const NodePtr &p): node(clone(p.node)) { }
+       NodePtr &operator=(const NodePtr &p) { delete node; node = clone(p.node); return *this; }
+       ~NodePtr() { delete node; }
+
+private:
+       static T *clone(T *n) { return n ? n->clone() : 0; }
+
+public:
+       T *operator->() { return node; }
+       const T *operator->() const { return node; }
+       operator void *() const { return node; }
+};
+
+struct VariableDeclaration;
+
 struct Block: Node
 {
-       std::vector<Node *> body;
+       std::vector<NodePtr<Node> > body;
        bool use_braces;
 
        Block();
-       virtual ~Block();
 
+       virtual Block *clone() const { return new Block(*this); }
+       virtual void visit(NodeVisitor &);
+};
+
+struct Expression: Node
+{
+       virtual Expression *clone() const = 0;
+};
+
+struct Literal: Expression
+{
+       std::string token;
+
+       virtual Literal *clone() const { return new Literal(*this); }
+       virtual void visit(NodeVisitor &);
+};
+
+struct ParenthesizedExpression: Expression
+{
+       NodePtr<Expression> expression;
+
+       virtual ParenthesizedExpression *clone() const { return new ParenthesizedExpression(*this); }
+       virtual void visit(NodeVisitor &);
+};
+
+struct VariableReference: Expression
+{
+       std::string name;
+
+       virtual VariableReference *clone() const { return new VariableReference(*this); }
+       virtual void visit(NodeVisitor &);
+};
+
+struct MemberAccess: Expression
+{
+       NodePtr<Expression> left;
+       std::string member;
+
+       virtual MemberAccess *clone() const { return new MemberAccess(*this); }
+       virtual void visit(NodeVisitor &);
+};
+
+struct UnaryExpression: Expression
+{
+       std::string oper;
+       NodePtr<Expression> expression;
+       bool prefix;
+
+       UnaryExpression();
+
+       virtual UnaryExpression *clone() const { return new UnaryExpression(*this); }
        virtual void visit(NodeVisitor &);
 };
 
-struct Expression
+struct BinaryExpression: Expression
 {
-       std::vector<std::string> tokens;
+       NodePtr<Expression> left;
+       std::string oper;
+       NodePtr<Expression> right;
+       std::string after;
+       bool assignment;
+
+       BinaryExpression();
 
-       bool empty() const { return tokens.empty(); }
+       virtual BinaryExpression *clone() const { return new BinaryExpression(*this); }
+       virtual void visit(NodeVisitor &);
+};
+
+struct FunctionCall: Expression
+{
+       std::string name;
+       bool constructor;
+       std::vector<NodePtr<Expression> > arguments;
+
+       FunctionCall();
+
+       virtual FunctionCall *clone() const { return new FunctionCall(*this); }
+       virtual void visit(NodeVisitor &);
 };
 
 struct ExpressionStatement: Node
 {
-       Expression expression;
+       NodePtr<Expression> expression;
 
+       virtual ExpressionStatement *clone() const { return new ExpressionStatement(*this); }
        virtual void visit(NodeVisitor &);
 };
 
@@ -54,6 +151,7 @@ struct Layout: Node
        std::vector<Qualifier> qualifiers;
        std::string interface;
 
+       virtual Layout *clone() const { return new Layout(*this); }
        virtual void visit(NodeVisitor &);
 };
 
@@ -64,6 +162,7 @@ struct StructDeclaration: Node
 
        StructDeclaration();
 
+       virtual StructDeclaration *clone() const { return new StructDeclaration(*this); }
        virtual void visit(NodeVisitor &);
 };
 
@@ -75,11 +174,12 @@ struct VariableDeclaration: Node
        std::string type;
        std::string name;
        bool array;
-       Expression array_size;
-       Expression init_expression;
+       NodePtr<Expression> array_size;
+       NodePtr<Expression> init_expression;
 
        VariableDeclaration();
 
+       virtual VariableDeclaration *clone() const { return new VariableDeclaration(*this); }
        virtual void visit(NodeVisitor &);
 };
 
@@ -91,6 +191,7 @@ struct InterfaceBlock: Node
 
        InterfaceBlock();
 
+       virtual InterfaceBlock *clone() const { return new InterfaceBlock(*this); }
        virtual void visit(NodeVisitor &);
 };
 
@@ -98,42 +199,42 @@ struct FunctionDeclaration: Node
 {
        std::string return_type;
        std::string name;
-       std::vector<VariableDeclaration *> parameters;
+       std::vector<NodePtr<VariableDeclaration> > parameters;
        bool definition;
        Block body;
 
        FunctionDeclaration();
-       ~FunctionDeclaration();
 
+       virtual FunctionDeclaration *clone() const { return new FunctionDeclaration(*this); }
        virtual void visit(NodeVisitor &);
 };
 
 struct Conditional: Node
 {
-       Expression condition;
+       Expression *condition;
        Block body;
        Block else_body;
 
+       virtual Conditional *clone() const { return new Conditional(*this); }
        virtual void visit(NodeVisitor &);
 };
 
 struct Iteration: Node
 {
-       Node *init_statement;
-       Expression condition;
-       Expression loop_expression;
+       NodePtr<Node> init_statement;
+       NodePtr<Expression> condition;
+       NodePtr<Expression> loop_expression;
        Block body;
 
-       Iteration();
-       virtual ~Iteration();
-
+       virtual Iteration *clone() const { return new Iteration(*this); }
        virtual void visit(NodeVisitor &);
 };
 
 struct Return: Node
 {
-       Expression expression;
+       NodePtr<Expression> expression;
 
+       virtual Return *clone() const { return new Return(*this); }
        virtual void visit(NodeVisitor &);
 };
 
@@ -142,6 +243,13 @@ struct NodeVisitor
        virtual ~NodeVisitor() { }
 
        virtual void visit(Block &) { }
+       virtual void visit(Literal &) { }
+       virtual void visit(ParenthesizedExpression &) { }
+       virtual void visit(VariableReference &) { }
+       virtual void visit(MemberAccess &) { }
+       virtual void visit(UnaryExpression &) { }
+       virtual void visit(BinaryExpression &) { }
+       virtual void visit(FunctionCall &) { }
        virtual void visit(ExpressionStatement &) { }
        virtual void visit(Layout &) { }
        virtual void visit(StructDeclaration &) { }