Add FORM-based source provider

form/CMakeLists.txt

@@ -32,3 +32,9 @@ target_link_libraries(form_module PRIVATE phlex::module form)
 target_include_directories(form_module PRIVATE ${PROJECT_SOURCE_DIR})
 
 install(TARGETS form_module LIBRARY DESTINATION lib)
+
+add_library(form_source MODULE form_source.cpp)
+target_link_libraries(form_source PRIVATE phlex::module form)
+target_include_directories(form_source PRIVATE ${PROJECT_SOURCE_DIR})
+install(TARGETS form_source LIBRARY DESTINATION lib)
+

form/form_source.cpp

@@ -0,0 +1,83 @@
+#include "phlex/source.hpp"
+
+#include "form/config.hpp"
+#include "form/form.hpp"
+#include "form/technology.hpp"
+
+#include <iostream>
+#include <memory>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+#include <vector>
+
+using namespace phlex;
+using namespace phlex::experimental::literals;
+
+PHLEX_REGISTER_PROVIDERS(s, config)
+{
+  std::cout << "Registering FORM source providers...\n";
+
+  // --- Extract configuration ---
+  std::string const input_file = config.get<std::string>("input_file");
+  std::string const creator = config.get<std::string>("creator");
+  std::string const tech_string = config.get<std::string>("technology", "ROOT_TTREE");
+
+  std::cout << "Configuration:\n";
+  std::cout << "  input_file:  " << input_file << "\n";
+  std::cout << "  creator:     " << creator << "\n";
+  std::cout << "  technology:  " << tech_string << "\n";
+
+  // --- Resolve technology enum ---
+  std::unordered_map<std::string_view, int> const tech_lookup = {
+    {"ROOT_TTREE", form::technology::ROOT_TTREE},
+    {"ROOT_RNTUPLE", form::technology::ROOT_RNTUPLE},
+    {"HDF5", form::technology::HDF5}};
+
+  auto it = tech_lookup.find(tech_string);
+  if (it == tech_lookup.end()) {
+    throw std::runtime_error("Unknown technology: " + tech_string);
+  }
+  int const technology = it->second;
+
+  // --- Build input config ---
+  form::experimental::config::output_item_config input_cfg;
+  form::experimental::config::tech_setting_config tech_cfg;
+  input_cfg.addItem("i", input_file, technology);
+  input_cfg.addItem("j", input_file, technology);
+
+  // --- Create shared form_interface ---
+  auto reader = std::make_shared<form::experimental::form_interface>(input_cfg, tech_cfg);
+
+  // --- Register providers ---
+  // FIXME: Prototype 0.1 -- product names and types hardcoded.
+  // product_query fields must be compile-time _id literals, not runtime strings.
+  // To add new products, add new s.provide() blocks below following the same pattern.
+
+  s.provide("provide_i",
+            [reader, creator](data_cell_index const& id) -> int {
+              std::cout << "\n=== form_source: providing i ===\n";
+              form::experimental::product_with_name pb{"i", nullptr, &typeid(int)};
+              reader->read(creator, id.to_string(), pb);
+              if (!pb.data) {
+                throw std::runtime_error("FORM read returned null data for product: i");
+              }
+              return *static_cast<int const*>(pb.data);
+            })
+    .output_product(product_query{.creator = "input"_id, .layer = "event"_id, .suffix = "i"_id});
+
+  s.provide("provide_j",
+            [reader, creator](data_cell_index const& id) -> int {
+              std::cout << "\n=== form_source: providing j ===\n";
+              form::experimental::product_with_name pb{"j", nullptr, &typeid(int)};
+              reader->read(creator, id.to_string(), pb);
+              if (!pb.data) {
+                throw std::runtime_error("FORM read returned null data for product: j");
+              }
+              return *static_cast<int const*>(pb.data);
+            })
+    .output_product(product_query{.creator = "input"_id, .layer = "event"_id, .suffix = "j"_id});
+
+  std::cout << "FORM source providers registered successfully\n";
+}