Used columns in col_vals_expr() are extracted lazily

R/col_vals_expr.R

@@ -339,10 +339,6 @@ col_vals_expr <- function(
     }
   }
 
-  # Extract columns from expr
-  data_cols <- colnames(apply_preconditions_for_cols(x, preconditions))
-  columns <- all_data_vars(expr, data_cols)
-
   # Resolve segments into list
   segments_list <- 
     resolve_segments(
@@ -404,7 +400,7 @@ col_vals_expr <- function(
         assertion_type = "col_vals_expr",
         i_o = i_o,
         columns_expr = NA_character_,
-        column = columns,
+        column = NA_character_,
         values = expr,
         preconditions = preconditions,
         seg_expr = segments,

R/interrogate.R

@@ -311,6 +311,13 @@ interrogate <- function(
           assertion_type = assertion_type
         )
 
+      if (assertion_type == "col_vals_expr") {
+        # Extract columns from expr and update validation set with used columns
+        expr <- get_values_at_idx(agent = agent, idx = i)[[1]]
+        columns <- all_data_vars(expr, data_cols = colnames(table))
+        agent$validation_set[[i, "column"]] <- list(columns)
+      }
+
     } else if (assertion_type == "conjointly") {
 
       validation_formulas <- get_values_at_idx(agent = agent, idx = i)

tests/testthat/test-interrogate_simple.R

@@ -2155,3 +2155,28 @@ test_that("class preserved in `value`", {
   expect_true(agent$validation_set$eval_error)
 
 })
+
+test_that("col_vals_expr extracts used columns lazily", {
+
+  agent_uninterrogated <- create_agent(tbl = iris) |> 
+    col_vals_expr(~ Petal.Length > Petal.Width)
+  expect_equal(
+    agent_uninterrogated$validation_set$column[[1]],
+    NA_character_
+  )
+
+  agent_interrogated <- agent_uninterrogated %>% 
+    interrogate()
+  expect_equal(
+    agent_interrogated$validation_set$column[[1]],
+    c("Petal.Length", "Petal.Width")
+  )
+
+  agent_inactive <- create_agent(tbl = iris) |> 
+    col_vals_expr(~ Petal.Length > Petal.Width, active = FALSE)
+  expect_equal(
+    agent_inactive$validation_set$column[[1]],
+    NA_character_
+  )
+
+})