add fixed_round as a separate function

Author: scgkiran

extensions/functions_rounding.yaml

@@ -356,5 +356,54 @@ scalar_functions:
               AWAY_FROM_ZERO, TIE_DOWN, TIE_UP, TIE_TOWARDS_ZERO, TIE_TO_ODD ]
         nullability: DECLARED_OUTPUT
         return: |-
-          S2 = iff(s > 0, s, 0)
-          decimal?<P1,S2>
+          decimal?<38,S1>
+  -
+    name: "fixed_round"
+    description: >
+      Rounding the value `x` to `s` decimal places.
+    impls:
+      - args:
+          - value: decimal<P1,S1>
+            name: "x"
+            description: >
+              Numerical expression to be rounded.
+          - value: decimal<38,0>
+            constant: true
+            name: "s"
+            description: >
+              Number of decimal places to be rounded to.
+
+              When `s` is a positive number, the rounding
+              is performed to a `s` number of decimal places.
+
+              When `s` is a negative number, the rounding is
+              performed to the left side of the decimal point
+              as specified by `s`.
+        options:
+          rounding:
+            description: >
+              When a boundary is computed to lie somewhere between two values,
+              and this value cannot be exactly represented, this specifies how
+              to round it.
+
+                - TIE_TO_EVEN: round to nearest value; if exactly halfway, tie
+                  to the even option.
+                - TIE_AWAY_FROM_ZERO: round to nearest value; if exactly
+                  halfway, tie away from zero.
+                - TRUNCATE: always round toward zero.
+                - CEILING: always round toward positive infinity.
+                - FLOOR: always round toward negative infinity.
+                - AWAY_FROM_ZERO: round negative values with FLOOR rule, round positive values with CEILING rule
+                - TIE_DOWN: round ties with FLOOR rule
+                - TIE_UP: round ties with CEILING rule
+                - TIE_TOWARDS_ZERO: round ties with TRUNCATE rule
+                - TIE_TO_ODD: round to nearest value; if exactly halfway, tie
+                  to the odd option.
+            values: [ TIE_TO_EVEN, TIE_AWAY_FROM_ZERO, TRUNCATE, CEILING, FLOOR,
+                      AWAY_FROM_ZERO, TIE_DOWN, TIE_UP, TIE_TOWARDS_ZERO, TIE_TO_ODD ]
+        nullability: DECLARED_OUTPUT
+        return: |-
+          S2 = (s > 0) ? min(s, S1) : 0
+          P2 = (s > 0) ? ((S1 >= s) ? P1 : (P1 + 1)) : ((P1 + s >= S1) ? P1 + 1 : (S1 - s + 1))
+          P2 = min(38, P2);
+          decimal?<P2,S2>