reactive_session.hpp

 
#pragma once
 
#include <nk/core/ast.hpp>
#include <nk/core/dependency_graph.hpp>
#include <nk/core/types.hpp>
#include <nk/figure/figure_manager.hpp>
 
#include <cstdint>
#include <memory>
#include <set>
#include <string>
#include <vector>
 
namespace nk {
 
class Engine;
 
class ReactiveSession
{
public:
    explicit ReactiveSession(Engine &engine);

    bool load(const std::string &source);

    void setParam(const std::string &var, Value value);

    void setParamElement(const std::string &var, size_t r, size_t c,
                         Value value);

    size_t evalDirty();

    bool hasDirty() const { return !dirty_.empty(); }

    std::vector<std::vector<size_t>> detectCycles() const;
 
    const DependencyGraph &graph() const { return *graph_; }
    size_t statementCount() const { return statements_.size(); }
    const std::string &lastError() const { return lastError_; }

    uint64_t generation() const { return generation_; }
 
private:
    void markDirty(const std::vector<size_t> &indices);
    Value runStatement(size_t index);
 
    Engine &engine_;
    std::shared_ptr<const std::string> src_;
    std::vector<ASTNodePtr> statements_;   // program children (owned)
    std::unique_ptr<DependencyGraph> graph_;
    // Figure-state rollback points, one per statement (captured after
    // that statement ran). evalDirty restores the checkpoint of the
    // last CLEAN statement before the dirty set, so re-run graphics
    // statements reproduce the full-re-run figure (no `hold on`
    // line accumulation across ticks).
    std::vector<FigureManager::FigureCheckpoint> checkpoints_;
    // Figure state captured in load() BEFORE the first statement runs
    // (may hold a PREVIOUS script's figures — sessions share the
    // engine). The rollback target when a dirty set starts at 0.
    FigureManager::FigureCheckpoint preScriptCp_;
    std::set<size_t> dirty_;
    std::set<std::string> params_;   // externally-set variables
    std::string lastError_;
    uint64_t generation_ = 0;
};
 
}  // namespace nk