Revert "fix: update arrow_cast function to accept string type for data_type parameter"

This reverts commit 9e1ced7.

Author: kosiew

python/datafusion/functions.py

@@ -1100,9 +1100,9 @@ def arrow_typeof(arg: Expr) -> Expr:
     return Expr(f.arrow_typeof(arg.expr))
 
 
-def arrow_cast(expr: Expr, data_type: str) -> Expr:
+def arrow_cast(expr: Expr, data_type: Expr) -> Expr:
     """Casts an expression to a specified data type."""
-    return Expr(f.arrow_cast(expr.expr, data_type))
+    return Expr(f.arrow_cast(expr.expr, data_type.expr))
 
 
 def random() -> Expr:

src/functions.rs

@@ -144,12 +144,6 @@ fn concat_ws(sep: String, args: Vec<PyExpr>) -> PyResult<PyExpr> {
     Ok(functions::string::expr_fn::concat_ws(lit(sep), args).into())
 }
 
-/// Casts an expression to a specified data type.
-#[pyfunction]
-fn arrow_cast(expr: PyExpr, data_type: &str) -> PyResult<PyExpr> {
-    Ok(functions::expr_fn::arrow_cast(expr.expr, data_type.to_string()).into())
-}
-
 #[pyfunction]
 #[pyo3(signature = (values, regex, flags=None))]
 fn regexp_like(values: PyExpr, regex: PyExpr, flags: Option<PyExpr>) -> PyResult<PyExpr> {
@@ -569,6 +563,7 @@ expr_fn_vec!(r#struct); // Use raw identifier since struct is a keyword
 expr_fn_vec!(named_struct);
 expr_fn!(from_unixtime, unixtime);
 expr_fn!(arrow_typeof, arg_1);
+expr_fn!(arrow_cast, arg_1 datatype);
 expr_fn!(random);
 
 // Array Functions