feat(smoking): Add smoking variable harmonization (CEP-002)

R/file-sourcing.R

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+# ==============================================================================
+# Robust File Sourcing with Centralized Configuration
+# ==============================================================================
+#
+# Configuration-based sourcing that uses here() with a single directory reference.
+# Change DEVELOPMENT_R_DIR once to switch between development/production modes.
+#
+# Usage patterns:
+# 1. R-to-R files: Use source_r_robust() (recommended) or source_r_with_fallback() (legacy)
+# 2. Metadata files: Use here::here("inst", "extdata", ...)
+# 3. Tests: Run from project root with testthat::test_file()
+#
+# DEVELOPMENT STATUS: Robust sourcing with centralized configuration
+# LOCATION: development/flexible-missing-data-mvp/R/file-sourcing.R
+
+# In package context, all R/ files are loaded automatically.
+# The here package is not needed; DEVELOPMENT_R_DIR is only used outside package context.
+DEVELOPMENT_R_DIR <- tryCatch(
+  here::here("development", "flexible-missing-data-mvp", "R"),
+  error = function(e) ""
+)
+
+# ==============================================================================
+# ROBUST SOURCING FUNCTIONS
+# ==============================================================================
+
+#' Robust R file sourcing with centralized configuration
+#'
+#' Sources R files using centralized directory configuration. 
+#' Change DEVELOPMENT_R_DIR once to switch between dev/prod/test modes.
+#'
+#' @param filename Character. Name of R file to source
+#' @param check_function Character. Function name to check if already loaded
+#' @param verbose Logical. Print sourcing information
+#' @export
+source_r_robust <- function(filename, check_function = NULL, verbose = FALSE) {
+
+  # Skip if function already exists
+  if (!is.null(check_function) && exists(check_function)) {
+    if (verbose) cat("✓", check_function, "already loaded\n")
+    return(TRUE)
+  }
+
+  # Construct path using centralized configuration
+  source_path <- file.path(DEVELOPMENT_R_DIR, filename)
+
+  if (nzchar(source_path) && file.exists(source_path)) {
+    if (verbose) cat("Loading", filename, "from", source_path, "\n")
+    source(source_path)
+    return(TRUE)
+  } else {
+    # In package context, all functions are already available via R/ loading
+    if (verbose) cat("Skipping", filename, "(package context)\n")
+    return(TRUE)
+  }
+}
+
+