feat: add argument wrap_numerical in $cast()

R/expr__expr.R

@@ -1022,26 +1022,33 @@ Expr_to_physical = use_extendr_wrapper
 #' @param dtype DataType to cast to.
 #' @param strict If `TRUE` (default), an error will be thrown if cast failed at
 #' resolve time.
+#' @param wrap_numerical If `TRUE`, numeric casts wrap overflowing values instead
+#' of marking the cast as invalid.
+#'
 #' @return Expr
 #' @examples
-#' df = pl$DataFrame(a = 1:3, b = c(1, 2, 3))
+#' df = pl$DataFrame(a = 1:3, b = c(1, 2, 3), c = c(100, 200, 300))
 #' df$with_columns(
-#'   pl$col("a")$cast(pl$dtypes$Float64),
-#'   pl$col("b")$cast(pl$dtypes$Int32)
+#'   pl$col("a")$cast(pl$Float64),
+#'   pl$col("b")$cast(pl$Int32)
 #' )
 #'
 #' # strict FALSE, inserts null for any cast failure
-#' pl$lit(c(100, 200, 300))$cast(pl$dtypes$UInt8, strict = FALSE)$to_series()
+#' df$with_columns(pl$col("c")$cast(pl$UInt8, strict = FALSE))
+#'
+#' # wrap_numerical doesn't error in case of overflow but rather wraps the value
+#' # to fit in the datatype
+#' df$with_columns(pl$col("c")$cast(pl$UInt8, wrap_numerical = TRUE))
 #'
 #' # strict TRUE, raise any failure as an error when query is executed.
 #' tryCatch(
 #'   {
-#'     pl$lit("a")$cast(pl$dtypes$Float64, strict = TRUE)$to_series()
+#'     pl$lit("a")$cast(pl$Float64, strict = TRUE)$to_series()
 #'   },
 #'   error = function(e) e
 #' )
-Expr_cast = function(dtype, strict = TRUE) {
-  .pr$Expr$cast(self, dtype, strict)
+Expr_cast = function(dtype, strict = TRUE, wrap_numerical = FALSE) {
+  .pr$Expr$cast(self, dtype, strict, wrap_numerical)
 }
 
 #' Compute the square root of the elements

R/extendr-wrappers.R

@@ -526,7 +526,7 @@ RPolarsExpr$xor <- function(other) .Call(wrap__RPolarsExpr__xor, self, other)
 
 RPolarsExpr$to_physical <- function() .Call(wrap__RPolarsExpr__to_physical, self)
 
-RPolarsExpr$cast <- function(data_type, strict) .Call(wrap__RPolarsExpr__cast, self, data_type, strict)
+RPolarsExpr$cast <- function(data_type, strict, wrap_numerical) .Call(wrap__RPolarsExpr__cast, self, data_type, strict, wrap_numerical)
 
 RPolarsExpr$sort_with <- function(descending, nulls_last) .Call(wrap__RPolarsExpr__sort_with, self, descending, nulls_last)
 

src/rust/src/lazy/dsl.rs

@@ -227,14 +227,20 @@ impl RPolarsExpr {
         self.0.clone().to_physical().into()
     }
 
-    pub fn cast(&self, data_type: &RPolarsDataType, strict: bool) -> Self {
+    pub fn cast(&self, data_type: &RPolarsDataType, strict: bool, wrap_numerical: bool) -> Self {
+        use polars::chunked_array::cast::CastOptions;
         let dt = data_type.0.clone();
-        if strict {
-            self.0.clone().strict_cast(dt)
+
+        let options = if wrap_numerical {
+            CastOptions::Overflowing
+        } else if strict {
+            CastOptions::Strict
         } else {
-            self.0.clone().cast(dt)
-        }
-        .into()
+            CastOptions::NonStrict
+        };
+
+        let expr = self.0.clone().cast_with_options(dt, options);
+        expr.into()
     }
 
     pub fn sort_with(&self, descending: bool, nulls_last: bool) -> Self {