[Python] fixes for extreme math values (#3072)

* [Python] fixes for math extreme values

* fix: random differences

pyproject.toml

@@ -16,6 +16,7 @@ python-dateutil = "^2.8.2"
 fable-library = {path = "./build/fable-library-py", develop = true}
 pytest = "^6.2.4"
 black = {version = "^22.6.0", allow-prereleases = true}
+isort = "^5.10.1"
 
 [tool.pyright]
 reportMissingTypeStubs = false
@@ -36,6 +37,17 @@ reportImplicitStringConcatenation = true
 pythonVersion = "3.10"
 typeCheckingMode = "strict"
 
+[tool.isort]
+profile = "black"
+atomic = true
+lines_after_imports = 2
+lines_between_types = 1
+multi_line_output = 3            # corresponds to -m  flag
+include_trailing_comma = true    # corresponds to -tc flag
+line_length = 88
+known_third_party = ["cognite","pytest"]
+py_version=310
+
 [build-system]
 requires = ["poetry-core>=1.0.0"]
 build-backend = "poetry.core.masonry.api"

src/Fable.Transforms/Python/Fable2Python.fs

@@ -527,11 +527,8 @@ module Helpers =
 
     /// Replaces all '$' and `.`with '_'
     let clean (name: string) =
-        match name with
-        | "Infinity" -> "float('inf')"
-        | _ ->
-            (name, Naming.NoMemberPart)
-            ||> Naming.sanitizeIdent (fun _ -> false)
+        (name, Naming.NoMemberPart)
+        ||> Naming.sanitizeIdent (fun _ -> false)
 
     let unzipArgs (args: (Expression * Statement list) list) : Expression list * Statement list =
         let stmts = args |> List.map snd |> List.collect id
@@ -1579,6 +1576,8 @@ module Util =
             | _, (:? uint32 as x) -> makeNumber com ctx r value.Type "uint32" x
             | _, x when x = infinity -> Expression.name "float('inf')", []
             | _, x when x = -infinity -> Expression.name "float('-inf')", []
+            | _, (:? float as x) when Double.IsNaN(x) -> Expression.name "float('nan')", []
+            | _, (:? float32 as x) when Single.IsNaN(x) -> libCall com ctx r "types" "float32" [ Expression.constant "nan"], []
             | _, (:? float32 as x) -> makeNumber com ctx r value.Type "float32" x
             | _, (:? float as x) -> Expression.constant (x, ?loc = r), []
             | _ -> Expression.constant (x, ?loc = r), []

src/Fable.Transforms/Python/PythonPrinter.fs

@@ -1,6 +1,8 @@
 // fsharplint:disable InterfaceNames
 module Fable.Transforms.PythonPrinter
 
+open System
+
 open Fable
 open Fable.AST
 open Fable.AST.Python
@@ -562,8 +564,9 @@ module PrinterExtensions =
                 | :? float as value ->
                     let value = string value
                     printer.Print(value)
-                    // Print with at least one decimal place
-                    if value.IndexOf(".") = -1 && not (value.Contains("E")) then
+
+                    // Make sure it's a valid Python float (not int)
+                    if String.forall (fun char -> char = '-' || Char.IsDigit char) value then
                         printer.Print(".0")
                 | :? bool as value -> printer.Print(if value then "True" else "False")
                 | _ -> printer.Print(string value)

src/Fable.Transforms/Python/Replacements.fs

@@ -374,8 +374,9 @@ let applyOp (com: ICompiler) (ctx: Context) r t opName (args: Expr list) =
           [ left; right ] ->
             match argTypes with
             // Floor result of integer divisions (see #172)
-            | Number((Int8 | Int16 | Int32 | UInt8 | UInt16 | UInt32 | Int64 | UInt64 | BigInt),_) :: _ -> binOp BinaryDivide left right |> fastIntFloor
-            | _ -> binOp BinaryDivide left right
+            | Number((Int8 | Int16 | Int32 | UInt8 | UInt16 | UInt32 | Int64 | UInt64 | BigInt),_) :: _ ->
+                binOp BinaryDivide left right |> fastIntFloor
+            | _ ->  Helper.LibCall(com, "double", "divide", t, [ left; right ], argTypes, ?loc=r)
         | Operators.modulus, [ left; right ] -> binOp BinaryModulus left right
         | Operators.leftShift, [ left; right ] ->
             binOp BinaryShiftLeft left right
@@ -1446,15 +1447,17 @@ let operators (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr o
     | "Cos", _
     | "Cosh", _
     | "Exp", _
-    | "Log", _
     | "Log10", _
     | "Sin", _
     | "Sinh", _
-    | "Sqrt", _
     | "Tan", _
     | "Tanh", _ ->
         math r t args i.SignatureArgTypes i.CompiledName
         |> Some
+    | "Log", _
+    | "Sqrt", _ ->
+        Helper.LibCall(com, "double", i.CompiledName.ToLower(), t, args, i.SignatureArgTypes, ?thisArg = thisArg, ?loc = r)
+        |> Some
     | "Round", _ ->
         match args with
         | ExprType(Number(Decimal,_))::_ ->
@@ -1469,7 +1472,7 @@ let operators (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr o
             Helper.LibCall(com, "decimal", "truncate", t, args, i.SignatureArgTypes, ?thisArg = thisArg, ?loc = r)
             |> Some
         | _ ->
-            Helper.GlobalCall("math", t, args, i.SignatureArgTypes, memb = "trunc", ?loc = r)
+            Helper.ImportedCall("math", "trunc", t, args, i.SignatureArgTypes, ?loc = r)
             |> Some
     | "Sign", _ ->
         let args = toFloat com ctx r t args |> List.singleton
@@ -1480,12 +1483,12 @@ let operators (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr o
     | ("Infinity"
       | "InfinitySingle"),
       _ ->
-        Helper.GlobalIdent("Number", "POSITIVE_INFINITY", t, ?loc = r)
+        Helper.ImportedValue(com, "math", "inf", t)
         |> Some
     | ("NaN"
       | "NaNSingle"),
       _ ->
-        Helper.GlobalIdent("Number", "NaN", t, ?loc = r)
+        Helper.ImportedValue(com, "math", "nan", t)
         |> Some
     | "Fst", [ tup ] -> Get(tup, TupleIndex 0, t, r) |> Some
     | "Snd", [ tup ] -> Get(tup, TupleIndex 1, t, r) |> Some
@@ -2402,10 +2405,13 @@ let parseNum (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr op
 
     match i.CompiledName, args with
     | "IsNaN", [ _ ] when isFloat ->
-        Helper.GlobalCall("Number", t, args, memb = "isNaN", ?loc = r)
+        Helper.ImportedCall("math", "isnan", t, args, ?loc = r)
         |> Some
     | "IsInfinity", [ _ ] when isFloat ->
-        Helper.LibCall(com, "double", "isInfinity", t, args, i.SignatureArgTypes, ?loc = r)
+        Helper.ImportedCall("math", "isinf", t, args, ?loc = r)
+        |> Some
+    | "IsNegativeInfinity" , [ _ ] when isFloat ->
+         Helper.LibCall(com, "double", "is_negative_inf", t, args, i.SignatureArgTypes, ?loc = r)
         |> Some
     | ("Parse"
       | "TryParse") as meth,
@@ -2726,7 +2732,7 @@ let intrinsicFunctions (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisAr
     // Type: PowDouble : float -> int -> float
     // Usage: PowDouble x n
     | "PowDouble", None, _ ->
-        Helper.GlobalCall("math", t, args, i.SignatureArgTypes, memb = "pow", ?loc = r)
+        Helper.ImportedCall("math", "pow", t, args, i.SignatureArgTypes, ?loc = r)
         |> Some
     | "PowDecimal", None, _ ->
         Helper.LibCall(com, "decimal", "pow", t, args, i.SignatureArgTypes, ?loc = r)
@@ -3274,10 +3280,10 @@ let random (com: ICompiler) (ctx: Context) r t (i: CallInfo) (_: Expr option) (a
             | [ min; max ] -> min, max
             | _ -> FableError "Unexpected arg count for Random.Next" |> raise
 
-        Helper.LibCall(com, "util", "randomNext", t, [ min; max ], [ min.Type; max.Type ], ?loc = r)
+        Helper.LibCall(com, "util", "randint", t, [ min; max ], [ min.Type; max.Type ], ?loc = r)
         |> Some
     | "NextDouble" ->
-        Helper.GlobalCall("math", t, [], [], memb = "random")
+        Helper.ImportedCall("random", "random", t, [], [])
         |> Some
     | "NextBytes" ->
         let byteArray =

src/Fable.Transforms/Replacements.Util.fs

@@ -45,6 +45,9 @@ type Helper =
         let info = CallInfo.Create(?thisArg=thisArg, args=args, ?sigArgTypes=argTypes, ?genArgs=genArgs, ?memberRef=memberRef, ?isCons=isConstructor)
         Call(callee, info, returnType, loc)
 
+    static member ImportedValue(com, coreModule: string, coreMember: string, returnType: Type) =
+        makeImportUserGenerated None Any coreMember coreModule
+
     static member ImportedCall(path: string, selector: string, returnType: Type, args: Expr list,
                                 ?argTypes: Type list, ?genArgs, ?thisArg: Expr, ?hasSpread: bool, ?isConstructor: bool, ?loc: SourceLocation) =
         let callee = makeImportUserGenerated None Any selector path

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

@@ -1,4 +1,5 @@
 import asyncio
+
 from asyncio import Future, ensure_future
 from concurrent.futures import ThreadPoolExecutor
 from threading import Timer
@@ -21,6 +22,7 @@
 from .choice import Choice_makeChoice2Of2  # type: ignore
 from .task import TaskCompletionSource
 
+
 _T = TypeVar("_T")
 
 

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

@@ -17,6 +17,7 @@
 
 from .util import IDisposable
 
+
 _T = TypeVar("_T")
 _U = TypeVar("_U")
 _D = TypeVar("_D", bound=IDisposable)

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

@@ -84,14 +84,22 @@ def equals(a: int, b: int) -> bool:
     return a == b
 
 
-def try_parse(string: str, defValue: FSharpRef[int]) -> bool:
+def try_parse(string: str, def_value: FSharpRef[int]) -> bool:
     try:
-        defValue.contents = parse(string)
+        def_value.contents = parse(string)
         return True
     except Exception:
         return False
 
 
+def op_right_shift(a: int, num_bits: int) -> int:
+    return a >> num_bits
+
+
+def of_left_shift(a: int, num_bits: int) -> int:
+    return a << num_bits
+
+
 BigInteger = int
 
 __all__ = [

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

@@ -1,5 +1,6 @@
 import struct
 import sys
+
 from typing import Optional
 
 

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

@@ -1,4 +1,5 @@
 import unicodedata
+
 from enum import IntEnum
 from typing import Dict, Union
 

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

@@ -1,10 +1,12 @@
 import re
+
 from datetime import datetime, timedelta, timezone
 from typing import Any, Match, Optional
 
 from .types import FSharpRef
 from .util import DateKind
 
+
 formatRegExp = re.compile(r"(\w)\1*")
 
 

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

@@ -1,7 +1,10 @@
+import builtins
+
 from decimal import MAX_EMAX, MIN_EMIN, Decimal, getcontext
 
 from .types import FSharpRef
 
+
 getcontext().prec = 29
 
 get_zero = Decimal(0)
@@ -67,6 +70,10 @@ def equals(a: Decimal, b: Decimal) -> bool:
     return a == b
 
 
+def abs(a: Decimal) -> Decimal:
+    return builtins.abs(a)
+
+
 __all__ = [
     "equals",
     "try_parse",

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

@@ -1,8 +1,43 @@
+import math
+
+from math import copysign
 from typing import Any
 
 from .types import FSharpRef
 
 
+def divide(x: float, y: float) -> float:
+    """Divide two numbers.
+
+    Returns nan if y is 0.
+    """
+    if y == 0:
+        if x == 0:
+            return float("nan")
+        return float("inf") if copysign(1, x) == copysign(1, y) else float("-inf")
+
+    return x / y
+
+
+def log(x: float) -> float:
+    if x == 0:
+        return float("-inf")
+    elif x < 0:
+        return float("nan")
+    return math.log(x)
+
+
+def sqrt(x: float) -> float:
+    try:
+        return math.sqrt(x)
+    except ValueError:
+        return float("nan")
+
+
+def is_negative_inf(value: float) -> bool:
+    return math.isinf(value) and value < 0
+
+
 def parse(value: Any) -> float:
     try:
         return float(value)

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

@@ -1,26 +1,28 @@
-from abc import abstractmethod
 import inspect
+
+from abc import abstractmethod
 from typing import (
     Any,
     Callable,
+    Generic,
     List,
     Optional,
     Protocol,
     TypeVar,
     Union,
-    Generic,
     overload,
 )
 
-from .observable import IObservable, IObserver, Observer
-from .option import Option, some, value
 from .choice import (
-    FSharpChoice_2,
     Choice_tryValueIfChoice1Of2,
     Choice_tryValueIfChoice2Of2,
+    FSharpChoice_2,
 )
+from .observable import IObservable, IObserver, Observer
+from .option import Option, some, value
 from .util import IDisposable
 
+
 _T = TypeVar("_T")
 _U = TypeVar("_U")
 _V = TypeVar("_V")