restore original code with a fix for type

Author: dkuku

native/explorer/src/datatypes.rs

@@ -644,8 +644,6 @@ impl ExDecimal {
     }
 
     pub fn scale(self) -> usize {
-        if self.exp > 0 {
-
         // A positive `exp` represents an integer. Polars requires `scale == 0`
         // for integers. The case where `exp > 0` is handled by `.signed_coef`.
         if self.exp > 0 {

native/explorer/src/series/from_list.rs

@@ -240,16 +240,17 @@ pub fn s_from_list_decimal(
                     })
             }
 
-            TermType::Map => {
-                match item.decode::<ExDecimal>() {
-                    Ok(ex_decimal) => ex_decimal
-                        .signed_coef()
-                        .map(|coef| AnyValue::Decimal(coef, ex_decimal.scale())),
-                    Err(error) => Err(ExplorerError::Other(format!(
+            TermType::Map => item
+                .decode::<ExDecimal>()
+                .map_err(|error| {
+                    ExplorerError::Other(format!(
                         "cannot decode a valid decimal from term; check that `coef` fits into an `i128`. error: {error:?}"
-                    ))),
-                }
-            }
+                    ))
+                })
+                .and_then(|ex_decimal| {
+                    ex_decimal.signed_coef().map(|coef| AnyValue::Decimal(coef, ex_decimal.scale()))
+                }),
+
             TermType::Atom => Ok(AnyValue::Null),
 
             TermType::Float => item