/**/#include "Foundation.H"class istream;class ostream;class Token;class ProgramNodeBuilder;class ProgramNode;class StatementNode;class ExpressionNode;class CodeGenerator;class BytecodeStream;/**/class Scanner {public:    Scanner(istream&);    virtual ~Scanner();    virtual Token& Scan();private:    istream& _inputStream;};/**/class Parser {public:    Parser();    virtual ~Parser();    virtual void Parse(Scanner&, ProgramNodeBuilder&);};/**/class ProgramNodeBuilder {public:    ProgramNodeBuilder();/**/    virtual ProgramNode* NewVariable(        char* variableName    ) const;/**/    virtual ProgramNode* NewAssignment(        ProgramNode* variable, ProgramNode* expression    ) const;/**/    virtual ProgramNode* NewReturnStatement(        ProgramNode* value    ) const;/**/    virtual ProgramNode* NewCondition(        ProgramNode* condition,        ProgramNode* truePart, ProgramNode* falsePart    ) const;    // .../**/    ProgramNode* GetRootNode();private:    ProgramNode* _node;};/**/class ProgramNode {public:    // program node manipulation    virtual void GetSourcePosition(int& line, int& index);    // .../**/    // child manipulation    virtual void Add(ProgramNode*);    virtual void Remove(ProgramNode*);    // ...    virtual void Traverse(CodeGenerator&);protected:    ProgramNode();};/**/class CodeGenerator {public:    virtual void Visit(StatementNode*);    virtual void Visit(ExpressionNode*);    // ...protected:    CodeGenerator(BytecodeStream&);protected:    BytecodeStream& _output;};/**/class ExpressionNode : public ProgramNode {public:    ExpressionNode();    virtual void GetSourcePosition(int& line, int& index);    virtual void Add(ProgramNode*);    virtual void Remove(ProgramNode*);    virtual void Traverse(CodeGenerator&);protected:    List<ProgramNode*>* _children;};/**/void ExpressionNode::Traverse (CodeGenerator& cg) {    cg.Visit(this);    ListIterator<ProgramNode*> i(_children);    for (i.First(); !i.IsDone(); i.Next()) {        i.CurrentItem()->Traverse(cg);    }}/**/class Compiler {public:    Compiler();    virtual void Compile(istream&, BytecodeStream&);};/**/class  RISCCodeGenerator : public CodeGenerator {public:    RISCCodeGenerator(BytecodeStream&);    virtual void Visit(StatementNode*);    virtual void Visit(ExpressionNode*);    // ...};/**/void Compiler::Compile (    istream& input, BytecodeStream& output) {    Scanner scanner(input);    ProgramNodeBuilder builder;    Parser parser;    parser.Parse(scanner, builder);    RISCCodeGenerator generator(output);    ProgramNode* parseTree = builder.GetRootNode();    parseTree->Traverse(generator);}/**/