Ticket #10476: 10476_singular_interrupt.patch

sage/interfaces/expect.py

@@ -568 +568 @@
         return
 
     def _quit_string(self):
+        """
+        Return the string which will be used to quit the application.
+
+        EXAMPLES::
+
+            sage: gp._quit_string()
+            '\\q'
+            sage: maxima._quit_string()
+            'quit();'
+        """
         return 'quit'
 
+    def _send_interrupt(self):
+        """
+        Send an interrupt to the application.  This is used internally
+        by :meth:`interrupt`.
+        """
+        self._expect.sendline(self._quit_string())
+        self._expect.sendline(chr(3))
+
     def _local_tmpfile(self):
         """
         Return a filename that is used to buffer long command lines for this interface
@@ -829 +847 @@
             sage: singular._eval_using_file_cutoff = 4
             sage: singular._eval_line('for(int i=1;i<=3;i++){i=1;};', wait_for_prompt=False)
             ''
-            sage: singular.interrupt(timeout=3)  # sometimes very slow (up to 60s on sage.math, 2012)
-            False
+            sage: singular.interrupt()
+            True
             sage: singular._eval_using_file_cutoff = cutoff
 
         Last, we demonstrate that by default the execution of a command
@@ -933 +951 @@
         success = False
         try:
             for i in range(tries):
-                E.sendline(self._quit_string())
-                E.sendline(chr(3))
+                self._send_interrupt()
                 try:
                     E.expect(self._prompt, timeout=timeout)
                     success= True

sage/interfaces/singular.py

@@ -9 +9 @@
   singular(...), x.[tab] includes all singular commands.
 
 - Martin Albrecht (2006-03-06): This patch adds the equality symbol to
-
+  singular. Also fix problem in which " " as prompt means comparison
   will break all further communication with Singular.
 
 - Martin Albrecht (2006-03-13): added current_ring() and
@@ -373 +373 @@
         Expect.__init__(self,
                         name = 'singular',
                         prompt = prompt,
-                        command = "Singular -t --ticks-per-sec 1000", #no tty and fine grained cputime()
+                        # No tty, fine grained cputime(), don't display CTRL-C prompt
+                        command = "Singular -t --ticks-per-sec 1000 --cntrlc=a",
                         maxread = maxread,
                         server = server,
                         server_tmpdir = server_tmpdir,
@@ -455 +456 @@
         """
         return 'quit'
 
+    def _send_interrupt(self):
+        """
+        Send an interrupt and a semi-colon to Singular.
+
+        TESTS:
+
+        The semi-colon is needed to abort the current input line. The
+        following works without restarting Singular::
+
+            sage: from sage.tests.interrupt import interrupt_after_delay
+            sage: a = singular(1)
+            sage: _ = singular._expect.sendline('1+')  # unfinished input
+            sage: try:
+            ...    interrupt_after_delay()
+            ...    singular._expect_expr('>')  # interrupt this
+            ... except KeyboardInterrupt:
+            ...     pass
+            Control-C pressed.  Interrupting Singular. Please wait a few seconds...
+
+        We can still access a::
+
+            sage: 2*a
+            2
+        """
+        E = self._expect
+        E.sendline(chr(3))
+        E.sendline(';')
+
     def _read_in_file_command(self, filename):
         r"""
         EXAMPLES::