Fixing time constrained more (#1165)

mathics/builtin/datentime.py

@@ -34,9 +34,10 @@
 )
 from mathics.core.expression import Expression
 from mathics.core.list import ListExpression
-from mathics.core.symbols import Symbol, SymbolNull
+from mathics.core.symbols import Symbol
 from mathics.core.systemsymbols import (
     SymbolAborted,
+    SymbolAbsoluteTime,
     SymbolAutomatic,
     SymbolInfinity,
     SymbolRowBox,
@@ -109,11 +110,9 @@ def total_seconds(td):
 else:
     total_seconds = timedelta.total_seconds
 
-SymbolAbsoluteTime = Symbol("AbsoluteTime")
 SymbolDateObject = Symbol("DateObject")
 SymbolDateString = Symbol("DateString")
 SymbolGregorian = Symbol("Gregorian")
-SymbolPause = Symbol("Pause")
 
 
 class _Date:
@@ -1026,45 +1025,6 @@ def eval(self, year, evaluation):
         return ListExpression(year, Integer(month), Integer(day))
 
 
-class Pause(Builtin):
-    """
-    <url>:WMA link:https://reference.wolfram.com/language/ref/Pause.html</url>
-
-    <dl>
-    <dt>'Pause[n]'
-      <dd>pauses for $n$ seconds.
-    </dl>
-
-    >> Pause[0.5]
-    """
-
-    messages = {
-        "numnm": (
-            "Non-negative machine-sized number expected at " "position 1 in `1`."
-        ),
-    }
-
-    summary_text = "pause for a number of seconds"
-
-    def eval(self, n, evaluation):
-        "Pause[n_]"
-        sleeptime = n.to_python()
-        if not isinstance(sleeptime, (int, float)) or sleeptime < 0:
-            evaluation.message(
-                "Pause", "numnm", Expression(SymbolPause, from_python(n))
-            )
-            return
-
-        steps = int(1000 * sleeptime)
-        while steps > 0:
-            time.sleep(0.001)
-            if evaluation.timeout:
-                return SymbolNull
-            steps = steps - 1
-
-        return SymbolNull
-
-
 class SystemTimeZone(Predefined):
     """
     <url>

mathics/builtin/procedural.py

@@ -16,6 +16,7 @@
 environment.
 """
 
+import time
 
 from mathics.core.attributes import (
     A_HOLD_ALL,
@@ -24,6 +25,7 @@
     A_READ_PROTECTED,
 )
 from mathics.core.builtin import BinaryOperator, Builtin, IterationFunction
+from mathics.core.convert.python import from_python
 from mathics.core.evaluation import Evaluation
 from mathics.core.expression import Expression
 from mathics.core.interrupt import (
@@ -34,7 +36,7 @@
     WLThrowInterrupt,
 )
 from mathics.core.symbols import Symbol, SymbolFalse, SymbolNull, SymbolTrue
-from mathics.core.systemsymbols import SymbolMatchQ
+from mathics.core.systemsymbols import SymbolMatchQ, SymbolPause
 from mathics.eval.patterns import match
 
 SymbolWhich = Symbol("Which")
@@ -438,6 +440,48 @@ def eval(self, evaluation: Evaluation):
         raise AbortInterrupt
 
 
+class Pause(Builtin):
+    """
+    <url>:WMA link:https://reference.wolfram.com/language/ref/Pause.html</url>
+
+    <dl>
+    <dt>'Pause[n]'
+      <dd>pauses for at least $n$ seconds.
+    </dl>
+
+    >> Pause[0.5]
+    """
+
+    messages = {
+        "numnm": (
+            "Non-negative machine-sized number expected at " "position 1 in `1`."
+        ),
+    }
+
+    summary_text = "pause for a number of seconds"
+
+    # Number of timeout polls per second that we perform in looking
+    # for a timeout.
+    PAUSE_TICKS_PER_SECOND = 1000
+
+    def eval(self, n, evaluation: Evaluation):
+        "Pause[n_]"
+        sleeptime = n.to_python()
+        if not isinstance(sleeptime, (int, float)) or sleeptime < 0:
+            evaluation.message(
+                "Pause", "numnm", Expression(SymbolPause, from_python(n))
+            )
+            return
+
+        steps = int(self.PAUSE_TICKS_PER_SECOND * sleeptime)
+        for _ in range(steps):
+            time.sleep(1 / self.PAUSE_TICKS_PER_SECOND)
+            if evaluation.timeout:
+                return SymbolNull
+
+        return SymbolNull
+
+
 class Return(Builtin):
     """
     <url>:WMA link:

mathics/core/evaluation.py

@@ -141,7 +141,7 @@ def run_with_timeout_and_stack(request, timeout, evaluation):
     if success:
         return result
     else:
-        raise result[1].with_traceback(result[1], result[2])
+        raise result[1].with_traceback(result[2])
 
 
 class _Out(KeyComparable):

mathics/core/systemsymbols.py

@@ -191,6 +191,7 @@
 SymbolPath = Symbol("System`$Path")
 SymbolPattern = Symbol("System`Pattern")
 SymbolPatternTest = Symbol("System`PatternTest")
+SymbolPause = Symbol("System`Pause")
 SymbolPi = Symbol("System`Pi")
 SymbolPiecewise = Symbol("System`Piecewise")
 SymbolPlot = Symbol("System`Plot")

mathics/eval/sympy.py

@@ -1,21 +1,29 @@
 """
-Evaluation of sympy functions
+Evaluation of SymPy functions
 """
 
 import sys
 from queue import Queue
 from threading import Thread
+from typing import Optional
 
 import sympy
 
 import mathics.eval.tracing as tracing
 from mathics.core.convert.sympy import from_sympy, to_numeric_sympy_args
+from mathics.core.element import BaseElement
+from mathics.core.evaluation import Evaluation
 
 
-def eval_sympy_unconstrained(self, z, evaluation):
+def eval_sympy_unconstrained(
+    self, z: BaseElement, evaluation: Evaluation
+) -> Optional[BaseElement]:
     """
-    Evaluate an expression converting it to Sympy
-    and back to Mathics.
+    Evaluate element `z` converting it to SymPy and back to Mathics3.
+    If an exception is raised we return None.
+
+    This version is called not-wrapped in a thread on systems like
+    emscripten that do not support Python-style threading.
     """
     sympy_args = to_numeric_sympy_args(z, evaluation)
     if self.sympy_name is None:
@@ -27,13 +35,15 @@ def eval_sympy_unconstrained(self, z, evaluation):
         return
 
 
-def eval_sympy_with_timeout(self, z, evaluation):
+def eval_sympy_with_timeout(
+    self, z: BaseElement, evaluation: Evaluation
+) -> Optional[BaseElement]:
     """
-    Evaluate an expression converting it to Sympy,
-    and back to Mathics.
-    This version put the evaluation in a thread,
-    and check each some time if the evaluation
-    reached a timeout.
+    Evaluate an element `z` converting it to SymPy,
+    and back to Mathics3.
+    If an exception is raised we return None.
+
+    This version is run in a thread, and checked for evaluation timeout.
     """
 
     if evaluation.timeout is None:
@@ -66,9 +76,10 @@ def evaluate():
     if success:
         return result
     else:
-        raise result[0].with_traceback(result[1], result[2])
+        raise result[1].with_traceback(result[2])
 
 
+# Common top-level evaluation SymPy "eval" function:
 eval_sympy = (
     eval_sympy_unconstrained
     if sys.platform in ("emscripten",)