pre-order.h

#pragma once
 
#include <stack>
 
namespace Antares::Expressions::Nodes
{
// Forward-declaration is enough
 
class Node;
 
// PreOrder Iterator for AST
class ASTPreOrderIterator
{
    std::stack<Node*> nodeStack;
 
public:
    // Iterator type aliases
    using iterator_category = std::forward_iterator_tag;
    using value_type = Node;
    using difference_type = std::ptrdiff_t;
    using pointer = Node*;
    using reference = Node&;
 
    // Constructor
    explicit ASTPreOrderIterator(Node* root = nullptr);
 
    // Dereference operator
    reference operator*() const;
 
    // Pointer access operator
    pointer operator->() const;
 
    // Increment operator (pre-order traversal)
    ASTPreOrderIterator& operator++();
 
    // Equality comparison
    bool operator==(const ASTPreOrderIterator& other) const;
 
    // Inequality comparison
    bool operator!=(const ASTPreOrderIterator& other) const;
};
 
// AST container class to expose begin/end iterators
class AST
{
    Node* root;
 
public:
    explicit AST(Node* rootNode);
 
    // Begin iterator
    ASTPreOrderIterator begin();
 
    // End iterator (indicating traversal is complete)
    ASTPreOrderIterator end();
};
 
// PreOrder Iterator for AST const version
class ASTPreOrderIteratorConst
{
    std::stack<const Node*> nodeStack;
 
public:
    // Iterator type aliases
    using iterator_category = std::forward_iterator_tag;
    using value_type = Node;
    using difference_type = std::ptrdiff_t;
    using pointer = const Node*;
    using reference = const Node&;
 
    // Constructor
    explicit ASTPreOrderIteratorConst(const Node* root = nullptr);
 
    // Dereference operator
    reference operator*() const;
 
    // Pointer access operator
    pointer operator->() const;
 
    // Increment operator (pre-order traversal)
    ASTPreOrderIteratorConst& operator++();
 
    // Equality comparison
    bool operator==(const ASTPreOrderIteratorConst& other) const;
 
    // Inequality comparison
    bool operator!=(const ASTPreOrderIteratorConst& other) const;
};
 
// AST container class to expose begin/end iterators
class ASTconst
{
    const Node* root;
 
public:
    explicit ASTconst(const Node* rootNode);
 
    // Begin iterator
    ASTPreOrderIteratorConst begin();
 
    // End iterator (indicating traversal is complete)
    ASTPreOrderIteratorConst end();
};
} // namespace Antares::Expressions::Nodes