Merge lp:~wallyworld/storm/support-recursive-with into lp:~launchpad-committers/storm/lp

[Ian Booth]

Extend WITH expression to support recursion.

This branch extends with WITH expression to support recursion.

== Implementation ==

Add a new recursive attribute to With and change it's compiler to support it.

== Tests ==

There were no tests for With so I added some:
  expr.test_with()
  expr.test_with_recursive()

[lp:~wallyworld/storm/support-recursive-with]

397. By Ian Booth on 2011-09-08

Merge from mainline

[Free Ekanayaka (free.ekanayaka)]

Looks good to me with the 2 points below fixed. +1

[1]

+ def __init__(self, name, select, **kwargs):

Any particular reason for not writing this as:

+ def __init__(self, name, select, recursive=False):

?

It feels more explicit to me.

[2]

Please document the new recursive parameter in the class docstring, like:

class With(Expr):
     """Compiles to a simple (name AS expr) used in constructing WITH clauses.

     @param recursive: <description>
     """

and add a note about it in the NEWS file.

review: Approve

[Ian Booth (wallyworld)]

Hi

Thank you. I'll definitely make the changes you suggest below; I think
they are all excellent points.

On 08/11/11 21:17, Free Ekanayaka wrote:
> Review: Approve
>
> Looks good to me with the 2 points below fixed. +1
>
> [1]
>
> + def __init__(self, name, select, **kwargs):
>
> Any particular reason for not writing this as:
>
> + def __init__(self, name, select, recursive=False):
>
> ?
>
> It feels more explicit to me.
>
> [2]
>
> Please document the new recursive parameter in the class docstring, like:
>
> class With(Expr):
> """Compiles to a simple (name AS expr) used in constructing WITH clauses.
>
> @param recursive:<description>
> """
>
> and add a note about it in the NEWS file.
>

[lp:~wallyworld/storm/support-recursive-with]

398. By Ian Booth on 2011-11-09

Merge from main devel

399. By Ian Booth on 2011-11-09

Tweaks from code review

Unmerged revisions

399. By Ian Booth on 2011-11-09

Tweaks from code review

398. By Ian Booth on 2011-11-09

Merge from main devel

397. By Ian Booth on 2011-09-08

Merge from mainline

396. By Ian Booth on 2011-09-07

Extend WITH expression to support recursion

=== modified file 'NEWS'
--- NEWS	2011-10-19 09:10:03 +0000
+++ NEWS	2011-11-09 01:59:22 +0000
@@ -3,6 +3,7 @@
 
 Improvements
 ------------
+- Add support for generating recursive WITH clauses.
 
 Bug fixes
 ---------

=== modified file 'storm/expr.py'
--- storm/expr.py	2011-10-19 09:10:03 +0000
+++ storm/expr.py	2011-11-09 01:59:22 +0000
@@ -1515,15 +1515,22 @@
 from storm.expr import compile, Expr, SQL
 
 class With(Expr):
-    """Compiles to a simple (name AS expr) used in constructing WITH clauses."""
-
-    def __init__(self, name, select):
+    """Compiles to a simple (name AS expr) used in constructing WITH clauses.
+
+    @param recursive: If true, a recursive WITH clause is generated.
+    """
+    __slots__ = ("name", "select", "recursive")
+
+    def __init__(self, name, select, recursive=False):
         self.name = name
         self.select = select
+        self.recursive = recursive
 
 @compile.when(With)
 def compile_with(compile, with_expr, state):
     tokens = []
+    if with_expr.recursive:
+        tokens.append(" RECURSIVE ")
     tokens.append(compile(with_expr.name, state, token=True))
     tokens.append(" AS ")
     tokens.append(compile(with_expr.select, state))

=== modified file 'tests/expr.py'
--- tests/expr.py	2011-09-14 15:27:52 +0000
+++ tests/expr.py	2011-11-09 01:59:22 +0000
@@ -1839,6 +1839,20 @@
         self.assertEquals(select2.context, SELECT)
         self.assertEquals(order_by.context, COLUMN_NAME)
 
+    def test_with(self):
+        expr = With(elem2, Select(elem1))
+        state = State()
+        statement = compile(expr, state)
+        self.assertEquals(statement, "elem2 AS (SELECT elem1)")
+        self.assertEquals(state.parameters, [])
+
+    def test_with_recursive(self):
+        expr = With(elem2, Select(elem1), recursive=True)
+        state = State()
+        statement = compile(expr, state)
+        self.assertEquals(statement, " RECURSIVE elem2 AS (SELECT elem1)")
+        self.assertEquals(state.parameters, [])
+
     def test_except(self):
         expr = Except(Func1(), elem2, elem3)
         state = State()