feat(isthmus): support bitwise left shift (#605)

Signed-off-by: Mark S. Lewis <[email protected]>

Author: bestbeforetoday

isthmus/src/main/java/io/substrait/isthmus/expression/FunctionMappings.java

@@ -86,7 +86,9 @@ public class FunctionMappings {
               s(SqlStdOperatorTable.IS_DISTINCT_FROM, "is_distinct_from"),
               s(SqlLibraryOperators.LOG2, "log2"),
               s(SqlLibraryOperators.LEAST, "least"),
-              s(SqlLibraryOperators.GREATEST, "greatest"))
+              s(SqlLibraryOperators.GREATEST, "greatest"),
+              s(SqlStdOperatorTable.BIT_LEFT_SHIFT, "shift_left"),
+              s(SqlStdOperatorTable.LEFTSHIFT, "shift_left"))
           .build();
 
   public static final ImmutableList<Sig> AGGREGATE_SIGS =
@@ -131,7 +133,9 @@ public class FunctionMappings {
           resolver(
               SqlStdOperatorTable.MINUS, Set.of("i8", "i16", "i32", "i64", "fp32", "fp64", "dec")),
           SqlStdOperatorTable.MINUS_DATE,
-          resolver(SqlStdOperatorTable.MINUS_DATE, Set.of("date", "timestamp_tz", "timestamp")));
+          resolver(SqlStdOperatorTable.MINUS_DATE, Set.of("date", "timestamp_tz", "timestamp")),
+          SqlStdOperatorTable.BIT_LEFT_SHIFT,
+          resolver(SqlStdOperatorTable.BIT_LEFT_SHIFT, Set.of("i8", "i16", "i32", "i64")));
 
   public static void main(String[] args) {
     SCALAR_SIGS.forEach(System.out::println);

isthmus/src/test/java/io/substrait/isthmus/ArithmeticFunctionTest.java

@@ -206,4 +206,18 @@ void factorial(String column) throws Exception {
     String query = String.format("SELECT FACTORIAL(%s) FROM numbers", column);
     assertFullRoundTrip(query, CREATES);
   }
+
+  @ParameterizedTest
+  @ValueSource(strings = {"i8", "i16", "i32", "i64"})
+  void bit_left_shift(String column) throws Exception {
+    String query = String.format("SELECT %s << 1 FROM numbers", column);
+    assertFullRoundTrip(query, CREATES);
+  }
+
+  @ParameterizedTest
+  @ValueSource(strings = {"i8", "i16", "i32", "i64"})
+  void leftshift(String column) throws Exception {
+    String query = String.format("SELECT LEFTSHIFT(%s, 1) FROM numbers", column);
+    assertFullRoundTrip(query, CREATES);
+  }
 }