[Python] Fix dictionary delete with tuples as keys (#3621)

* Fix python dictionary delete

* Update changelog

src/Fable.Cli/CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 #### Python
 
 * Fix #3617: Fix comparaison between list option when one is None
+* Fix #3615: Fix remove from dictionary with tuple as key
+* Fix #3598: Using obj () now generated an empty dict instead of None
 
 ## 4.6.0 - 2023-11-27
 

src/Fable.Transforms/Python/Fable2Python.fs

@@ -1525,6 +1525,7 @@ module Util =
         | "set" -> Expression.identifier "__setitem__"
         | "get" -> Expression.identifier "__getitem__"
         | "has" -> Expression.identifier "__contains__"
+        | "delete" -> Expression.identifier "__delitem__"
         | n when n.EndsWith "get_Count" -> Expression.identifier "__len__" // TODO: find a better way
         | n when n.StartsWith("Symbol.iterator") ->
             let name = Identifier "__iter__"
@@ -1859,7 +1860,6 @@ module Util =
 
     let getUnionExprTag (com: IPythonCompiler) ctx r (fableExpr: Fable.Expr) =
         let expr, stmts = com.TransformAsExpr(ctx, fableExpr)
-
         let expr, stmts' = getExpr com ctx r expr (Expression.constant "tag")
 
         expr, stmts @ stmts'
@@ -3934,7 +3934,7 @@ module Util =
             transformFunctionWithAnnotations com ctx name args body
             |||> makeArrowFunctionExpression com ctx name
 
-        | Fable.ObjectExpr([], _typ, None) -> Expression.none, []
+        | Fable.ObjectExpr([], _typ, None) -> Expression.dict (), []
         | Fable.ObjectExpr(members, typ, baseCall) ->
             // printfn "members: %A" (members, typ)
             transformObjectExpr com ctx members typ baseCall

src/Fable.Transforms/Python/Python.fs

@@ -1048,6 +1048,8 @@ module PythonExtensions =
             }
             |> Dict
 
+        static member dict() : Expression = Expression.dict ([], [])
+
         static member tuple(elts, ?loc) : Expression =
             {
                 Elements = elts

src/Fable.Transforms/Python/PythonPrinter.fs

@@ -479,23 +479,27 @@ module PrinterExtensions =
 
         member printer.Print(node: Dict) =
             printer.Print("{")
-            printer.PrintNewLine()
-            printer.PushIndentation()
 
-            let nodes =
-                List.zip node.Keys node.Values |> List.mapi (fun i n -> (i, n))
+            if not node.Keys.IsEmpty then
+                printer.PrintNewLine()
+                printer.PushIndentation()
 
-            for i, (key, value) in nodes do
-                printer.Print(key)
-                printer.Print(": ")
-                printer.Print(value)
+                let nodes =
+                    List.zip node.Keys node.Values
+                    |> List.mapi (fun i n -> (i, n))
 
-                if i < nodes.Length - 1 then
-                    printer.Print(",")
-                    printer.PrintNewLine()
+                for i, (key, value) in nodes do
+                    printer.Print(key)
+                    printer.Print(": ")
+                    printer.Print(value)
+
+                    if i < nodes.Length - 1 then
+                        printer.Print(",")
+                        printer.PrintNewLine()
+
+                printer.PrintNewLine()
+                printer.PopIndentation()
 
-            printer.PrintNewLine()
-            printer.PopIndentation()
             printer.Print("}")
 
         member printer.Print(node: Name) =

src/fable-library-py/fable_library/date.py

@@ -5,9 +5,10 @@
 from re import Match
 from typing import Any
 
+from .time_span import TimeSpan
+from .time_span import create as create_time_span
 from .types import FSharpRef
 from .util import DateKind
-from .time_span import TimeSpan, create as create_time_span
 
 
 formatRegExp = re.compile(r"(\w)\1*")
@@ -17,8 +18,8 @@ def op_subtraction(x: datetime, y: datetime) -> TimeSpan:
     delta = x - y
     # ts.microseconds only contains the microseconds provided to the constructor
     # so we need to calculate the total microseconds ourselves
-    delta_microseconds = delta.days * (24*3600) + delta.seconds * 10**6 + delta.microseconds
-    return create_time_span(0,0,0,0,0,delta_microseconds)
+    delta_microseconds = delta.days * (24 * 3600) + delta.seconds * 10**6 + delta.microseconds
+    return create_time_span(0, 0, 0, 0, 0, delta_microseconds)
 
 
 def create(

tests/Python/TestDictionary.fs

@@ -233,3 +233,10 @@ let ``test Dictionary.Delete works`` () =
     dic.ContainsValue("Hello") |> equal true
     dic.Remove("A") |> equal true
     dic.ContainsValue("Hello") |> equal false
+
+[<Fact>]
+let ``test Dictionary.Delete works with tuples as keys`` () =
+    let my_dict = Dictionary((Map [for i in 0..10 do yield (i,i), sprintf "Number: %i" i]))
+    my_dict.ContainsKey((0,0)) |> equal true
+    my_dict.Remove((0,0)) |> equal true
+    my_dict.ContainsKey((0,0)) |> equal false