refactor: move FirstValue/LastValue to SQL-specific IR

ibis/backends/oracle/compiler.py

@@ -11,6 +11,8 @@
 from ibis.backends.sql.datatypes import OracleType
 from ibis.backends.sql.dialects import Oracle
 from ibis.backends.sql.rewrites import (
+    FirstValue,
+    LastValue,
     exclude_unsupported_window_frame_from_ops,
     exclude_unsupported_window_frame_from_row_number,
     replace_log2,
@@ -409,8 +411,8 @@ def visit_Window(self, op, *, how, func, start, end, group_by, order_by):
             ops.Correlation,  # "corr",
             ops.Count,  # "count",
             ops.Covariance,  # "covar_pop", "covar_samp",
-            ops.FirstValue,  # "first_value",
-            ops.LastValue,  # "last_value",
+            FirstValue,  # "first_value",
+            LastValue,  # "last_value",
             ops.Max,  # "max",
             ops.Min,  # "min",
             ops.NthValue,  # "nth_value",

ibis/backends/pandas/executor.py

@@ -452,15 +452,6 @@ def agg(df, order_keys):
 
         return agg
 
-    @classmethod
-    def visit(cls, op: ops.FirstValue | ops.LastValue, arg):
-        i = 0 if isinstance(op, ops.FirstValue) else -1
-
-        def agg(df, order_keys):
-            return df[arg.name].iat[i]
-
-        return agg
-
     @classmethod
     def visit(
         cls, op: ops.AnalyticVectorizedUDF, func, func_args, input_type, return_type

ibis/backends/sql/compiler.py

@@ -19,6 +19,8 @@
 import ibis.expr.datatypes as dt
 import ibis.expr.operations as ops
 from ibis.backends.sql.rewrites import (
+    FirstValue,
+    LastValue,
     add_one_to_nth_value_input,
     add_order_by_to_empty_ranking_window_functions,
     empty_in_values_right_side,
@@ -235,15 +237,15 @@ class SQLGlotCompiler(abc.ABC):
         ops.DenseRank: "dense_rank",
         ops.Exp: "exp",
         ops.First: "first",
-        ops.FirstValue: "first_value",
+        FirstValue: "first_value",
         ops.GroupConcat: "group_concat",
         ops.IfElse: "if",
         ops.IsInf: "isinf",
         ops.IsNan: "isnan",
         ops.JSONGetItem: "json_extract",
         ops.LPad: "lpad",
         ops.Last: "last",
-        ops.LastValue: "last_value",
+        LastValue: "last_value",
         ops.Levenshtein: "levenshtein",
         ops.Ln: "ln",
         ops.Log10: "log",

ibis/backends/sql/rewrites.py

@@ -62,6 +62,28 @@ def schema(self):
         return Schema({k: v.dtype for k, v in self.selections.items()})
 
 
+@public
+class FirstValue(ops.Analytic):
+    """Retrieve the first element."""
+
+    arg: ops.Column[dt.Any]
+
+    @attribute
+    def dtype(self):
+        return self.arg.dtype
+
+
+@public
+class LastValue(ops.Analytic):
+    """Retrieve the last element."""
+
+    arg: ops.Column[dt.Any]
+
+    @attribute
+    def dtype(self):
+        return self.arg.dtype
+
+
 @public
 class Window(ops.Value):
     """Window modelled after SQL's window statements."""
@@ -277,7 +299,7 @@ def rewrite_first_to_first_value(_, x, y, **kwargs):
         raise com.UnsupportedOperationError(
             "`first` with `where` is unsupported in a window function"
         )
-    return _.copy(func=ops.FirstValue(x))
+    return _.copy(func=FirstValue(x))
 
 
 @replace(p.WindowFunction(p.Last(x, where=y)))
@@ -287,7 +309,7 @@ def rewrite_last_to_last_value(_, x, y, **kwargs):
         raise com.UnsupportedOperationError(
             "`last` with `where` is unsupported in a window function"
         )
-    return _.copy(func=ops.LastValue(x))
+    return _.copy(func=LastValue(x))
 
 
 @replace(p.WindowFunction(frame=y @ p.WindowFrame(order_by=())))

ibis/expr/operations/analytic.py

@@ -89,24 +89,6 @@ class NTile(Analytic):
     dtype = dt.int64
 
 
-@public
-class FirstValue(Analytic):
-    """Retrieve the first element."""
-
-    arg: Column[dt.Any]
-
-    dtype = rlz.dtype_like("arg")
-
-
-@public
-class LastValue(Analytic):
-    """Retrieve the last element."""
-
-    arg: Column[dt.Any]
-
-    dtype = rlz.dtype_like("arg")
-
-
 @public
 class NthValue(Analytic):
     """Retrieve the Nth element."""