gh-36890: pep8 cleanup for gap interface
    
full pep8 cleanup for the gap interface

### 📝 Checklist

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
    
URL: #36890
Reported by: Frédéric Chapoton
Reviewer(s): David Coudert

Author: Release Manager

src/sage/interfaces/gap.py

@@ -177,7 +177,7 @@
   gap(...), x.[tab], and docs, e.g., gap.function? and x.function?
 """
 
-#*****************************************************************************
+# ****************************************************************************
 #       Copyright (C) 2005 William Stein <[email protected]>
 #
 #  Distributed under the terms of the GNU General Public License (GPL)
@@ -189,8 +189,8 @@
 #
 #  The full text of the GPL is available at:
 #
-#                  http://www.gnu.org/licenses/
-#*****************************************************************************
+#                  https://www.gnu.org/licenses/
+# ****************************************************************************
 
 from .expect import Expect, ExpectElement, FunctionElement, ExpectFunction
 from .gap_workspace import gap_workspace_file, prepare_workspace_dir
@@ -244,7 +244,7 @@ def gap_command(use_workspace_cache=True, local=True):
         return gap_cmd, True
 
 
-############ Classes with methods for both the GAP3 and GAP4 interface
+# ########### Classes with methods for both the GAP3 and GAP4 interface
 
 class Gap_generic(ExtraTabCompletion, Expect):
     r"""
@@ -287,10 +287,10 @@ def _synchronize(self, timeout=0.5, cmd='%s;'):
         E = self._expect
         from sage.misc.prandom import randrange
         rnd = randrange(2147483647)
-        cmd = str(rnd)+';'
+        cmd = str(rnd) + ';'
         try:
             E.sendline(cmd)
-            E.expect(r'@[nf][@J\s>]*'+str(rnd), timeout=timeout)
+            E.expect(r'@[nf][@J\s>]*' + str(rnd), timeout=timeout)
             E.send(' ')
             E.expect('@i', timeout=timeout)
         except pexpect.TIMEOUT:
@@ -453,7 +453,7 @@ def load_package(self, pkg, verbose=False):
             print("Loading GAP package {}".format(pkg))
         x = self.eval('LoadPackage("{}")'.format(pkg))
         if x == 'fail':
-            raise RuntimeError("Error loading Gap package "+str(pkg)+". " +
+            raise RuntimeError("Error loading Gap package " + str(pkg) + ". " +
                                "You may want to install gap_packages SPKG.")
 
     def eval(self, x, newlines=False, strip=True, split_lines=True, **kwds):
@@ -507,10 +507,10 @@ def eval(self, x, newlines=False, strip=True, split_lines=True, **kwds):
             '  -\n\\\\-'
         """
         # '"
-        #We remove all of the comments:  On each line, we try
-        #to find a pound sign.  If we find it, we check to see if
-        #it is occurring in a string.  If it is not in a string, we
-        #strip off the comment.
+        # We remove all of the comments:  On each line, we try
+        # to find a pound sign.  If we find it, we check to see if
+        # it is occurring in a string.  If it is not in a string, we
+        # strip off the comment.
         if not split_lines:
             input_line = str(x)
         else:
@@ -520,17 +520,17 @@ def eval(self, x, newlines=False, strip=True, split_lines=True, **kwds):
                 while pound_position != -1:
                     if not is_in_string(line, pound_position):
                         line = line[:pound_position]
-                    pound_position = line.find('#',pound_position+1)
-                input_line += " "+line
+                    pound_position = line.find('#', pound_position + 1)
+                input_line += " " + line
             if not input_line.endswith(';'):
                 input_line += ';'
         result = Expect.eval(self, input_line, **kwds)
         if not newlines:
-            result = result.replace("\\\n","")
+            result = result.replace("\\\n", "")
         return result.rstrip()
 
     def _execute_line(self, line, wait_for_prompt=True, expect_eof=False):
-        if self._expect is None: # interface is down
+        if self._expect is None:  # interface is down
             self._start()
         E = self._expect
         try:
@@ -540,9 +540,9 @@ def _execute_line(self, line, wait_for_prompt=True, expect_eof=False):
         except OSError:
             raise RuntimeError("Error evaluating %s in %s" % (line, self))
         if not wait_for_prompt:
-            return (b'',b'')
+            return (b'', b'')
         if len(line) == 0:
-            return (b'',b'')
+            return (b'', b'')
         try:
             terminal_echo = []   # to be discarded
             normal_outputs = []  # GAP stdout
@@ -556,43 +556,43 @@ def _execute_line(self, line, wait_for_prompt=True, expect_eof=False):
                         warnings.warn(
                             "possibly wrong version of GAP package "
                             "interface. Crossing fingers and continuing.")
-                elif x == 1: #@@
+                elif x == 1:  # @@
                     current_outputs.append(b'@')
-                elif x == 2: #special char
+                elif x == 2:  # special char
                     c = ord(E.after[1:2]) - ord(b'A') + 1
                     s = bytes([c])
                     current_outputs.append(s)
-                elif x == 3: # garbage collection info, ignore
+                elif x == 3:  # garbage collection info, ignore
                     pass
-                elif x == 4: # @e -- break loop
+                elif x == 4:  # @e -- break loop
                     E.sendline("quit;")
-                elif x == 5: # @c completion, doesn't seem to happen when -p is in use
+                elif x == 5:  # @c completion, doesn't seem to happen when -p is in use
                     warnings.warn("I didn't think GAP could do this")
-                elif x == 6: # @f GAP error message
+                elif x == 6:  # @f GAP error message
                     current_outputs = error_outputs
-                elif x == 7: # @h help text, but this stopped happening with new help
+                elif x == 7:  # @h help text, but this stopped happening with new help
                     warnings.warn("I didn't think GAP could do this")
-                elif x == 8: # @i awaiting normal input
+                elif x == 8:  # @i awaiting normal input
                     break
-                elif x == 9: # @m finished running a child
+                elif x == 9:  # @m finished running a child
                     pass   # there is no need to do anything
-                elif x == 10: #@n normal output line
+                elif x == 10:  # @n normal output line
                     current_outputs = normal_outputs
-                elif x == 11: #@r echoing input
+                elif x == 11:  # @r echoing input
                     current_outputs = terminal_echo
-                elif x == 12: #@sN shouldn't happen
+                elif x == 12:  # @sN shouldn't happen
                     warnings.warn("this should never happen")
-                elif x == 13: #@w GAP is trying to send a Window command
+                elif x == 13:  # @w GAP is trying to send a Window command
                     warnings.warn("this should never happen")
-                elif x == 14: #@x seems to be safely ignorable
+                elif x == 14:  # @x seems to be safely ignorable
                     pass
-                elif x == 15:#@z GAP starting a subprocess
+                elif x == 15:  # @z GAP starting a subprocess
                     pass  # there is no need to do anything
         except pexpect.EOF:
             if not expect_eof:
-                raise RuntimeError("Unexpected EOF from %s executing %s" % (self,line))
+                raise RuntimeError("Unexpected EOF from %s executing %s" % (self, line))
         except IOError:
-            raise RuntimeError("IO Error from %s executing %s" % (self,line))
+            raise RuntimeError("IO Error from %s executing %s" % (self, line))
         return (b"".join(normal_outputs), b"".join(error_outputs))
 
     def _keyboard_interrupt(self):
@@ -697,8 +697,8 @@ def _eval_line(self, line, allow_use_file=True, wait_for_prompt=True, restart_if
                     error += "\nRunning gap_reset_workspace()..."
                     self.quit()
                     gap_reset_workspace()
-                error = error.replace('\r','')
-                raise RuntimeError("%s produced error output\n%s\n   executing %s" % (self, error,line))
+                error = error.replace('\r', '')
+                raise RuntimeError("%s produced error output\n%s\n   executing %s" % (self, error, line))
             if not normal:
                 return ''
 
@@ -772,7 +772,7 @@ def _contains(self, v1, v2):
             sage: 2 in gap('Integers')
             True
         """
-        return self.eval('%s in %s' % (v1,v2)) == "true"
+        return self.eval('%s in %s' % (v1, v2)) == "true"
 
     def _true_symbol(self):
         """
@@ -868,20 +868,21 @@ def function_call(self, function, args=None, kwds=None):
         args, kwds = self._convert_args_kwds(args, kwds)
         self._check_valid_function_name(function)
 
-        #Here we have to do some magic because not all GAP
-        #functions return a value.  If you try to store their
-        #results to a variable, then GAP will complain.  Thus, before
-        #we evaluate the function, we make it so that the marker string
-        #is in the 'last' variable in GAP.  If the function returns a
-        #value, then that value will be in 'last', otherwise it will
-        #be the marker.
+        # Here we have to do some magic because not all GAP
+        # functions return a value.  If you try to store their
+        # results to a variable, then GAP will complain.  Thus, before
+        # we evaluate the function, we make it so that the marker string
+        # is in the 'last' variable in GAP.  If the function returns a
+        # value, then that value will be in 'last', otherwise it will
+        # be the marker.
         marker = '__SAGE_LAST__:="__SAGE_LAST__";;'
         cmd = "%s(%s);;" % (function, ",".join([s.name() for s in args] +
-                ['%s=%s' % (key,value.name()) for key, value in kwds.items()]))
+                                               [f'{key}={value.name()}'
+                                                for key, value in kwds.items()]))
         if len(marker) + len(cmd) <= self._eval_using_file_cutoff:
             # We combine the two commands so we only run eval() once and the
             #   only output would be from the second command
-            res = self.eval(marker+cmd)
+            res = self.eval(marker + cmd)
         else:
             self.eval(marker)
             res = self.eval(cmd)
@@ -1045,7 +1046,8 @@ def _matrix_(self, R):
 
         from sage.matrix.matrix_space import MatrixSpace
         M = MatrixSpace(R, n, m)
-        entries = [[R(self[r,c]) for c in range(1,m+1)] for r in range(1,n+1)]
+        entries = [[R(self[r, c]) for c in range(1, m + 1)]
+                   for r in range(1, n + 1)]
         return M(entries)
 
 
@@ -1099,7 +1101,7 @@ def __init__(self, max_workspace_size=None,
         self.__seq = 0
         self._seed = seed
 
-    def set_seed(self,seed=None):
+    def set_seed(self, seed=None):
         """
         Set the seed for gap interpreter.
 
@@ -1204,8 +1206,8 @@ def _start(self):
             self.save_workspace()
         # Now, as self._expect exists, we can compile some useful pattern:
         self._compiled_full_pattern = self._expect.compile_pattern_list([
-                r'@p\d+\.','@@','@[A-Z]',r'@[123456!"#$%&][^+]*\+',
-                '@e','@c','@f','@h','@i','@m','@n','@r',r'@s\d',r'@w.*\+','@x','@z'])
+            r'@p\d+\.', '@@', '@[A-Z]', r'@[123456!"#$%&][^+]*\+',
+            '@e', '@c', '@f', '@h', '@i', '@m', '@n', '@r', r'@s\d', r'@w.*\+', '@x', '@z'])
         # read everything up to the first "ready" prompt
         self._expect.expect("@i")
 
@@ -1246,10 +1248,9 @@ def cputime(self, t=None):
         """
         if t is not None:
             return self.cputime() - t
-        else:
-            self.eval('_r_ := Runtimes();')
-            r = sum(eval(self.eval('[_r_.user_time, _r_.system_time, _r_.user_time_children, _r_.system_time_children]')))
-            return r/1000.0
+        self.eval('_r_ := Runtimes();')
+        r = sum(eval(self.eval('[_r_.user_time, _r_.system_time, _r_.user_time_children, _r_.system_time_children]')))
+        return r / 1000.0
 
     def save_workspace(self):
         r"""
@@ -1349,7 +1350,7 @@ def set(self, var, value):
             sage: gap.get('x')
             '2'
         """
-        cmd = ('%s:=%s;;' % (var, value)).replace('\n','')
+        cmd = ('%s:=%s;;' % (var, value)).replace('\n', '')
         self._eval_line(cmd, allow_use_file=True)
 
     def get(self, var, use_file=False):
@@ -1366,10 +1367,10 @@ def get(self, var, use_file=False):
             tmp = self._local_tmpfile()
             if os.path.exists(tmp):
                 os.unlink(tmp)
-            self.eval('PrintTo("%s", %s);' % (tmp,var), strip=False)
+            self.eval('PrintTo("%s", %s);' % (tmp, var), strip=False)
             with open(tmp) as f:
                 r = f.read()
-            r = r.strip().replace("\\\n","")
+            r = r.strip().replace("\\\n", "")
             os.unlink(tmp)
             return r
         else:
@@ -1480,7 +1481,7 @@ def _tab_completion(self):
             True
         """
         names = eval(self.eval('NamesSystemGVars()')) + \
-                eval(self.eval('NamesUserGVars()'))
+            eval(self.eval('NamesUserGVars()'))
         return [n for n in names if n[0] in string.ascii_letters]
 
 
@@ -1582,16 +1583,16 @@ def _latex_(self):
         P = self._check_valid()
         try:
             s = P.eval('LaTeXObj(%s)' % self.name())
-            s = s.replace('\\\\','\\').replace('"','')
-            s = s.replace('%\\n',' ')
+            s = s.replace('\\\\', '\\').replace('"', '')
+            s = s.replace('%\\n', ' ')
             return s
         except RuntimeError:
             return str(self)
 
     @cached_method
     def _tab_completion(self):
         """
-        Return additional tab completion entries
+        Return additional tab completion entries.
 
         OUTPUT:
 
@@ -1605,10 +1606,11 @@ def _tab_completion(self):
         """
         P = self.parent()
         v = P.eval(r'\$SAGE.OperationsAdmittingFirstArgument(%s)' % self.name())
-        v = v.replace('Tester(','').replace('Setter(','').replace(')','').replace('\n', '')
+        v = v.replace('Tester(', '').replace('Setter(', '').replace(')', '').replace('\n', '')
         v = v.split(',')
-        v = [ oper.split('"')[1] for oper in v ]
-        v = [ oper for oper in v if all(ch in string.ascii_letters for ch in oper) ]
+        v = (oper.split('"')[1] for oper in v)
+        v = [oper for oper in v
+             if all(ch in string.ascii_letters for ch in oper)]
         return sorted(set(v))
 
 
@@ -1718,13 +1720,13 @@ def gfq_gap_to_sage(x, F):
         return F(0)
     i1 = s.index("(")
     i2 = s.index(")")
-    q = eval(s[i1+1:i2].replace('^','**'))
+    q = eval(s[i1 + 1:i2].replace('^', '**'))
     if not F.cardinality().is_power_of(q):
         raise ValueError('%r has no subfield of size %r' % (F, q))
     if s.find(')^') == -1:
         e = 1
     else:
-        e = int(s[i2+2:])
+        e = int(s[i2 + 2:])
     if F.degree() == 1:
         g = F(gap.eval('Int(Z(%s))' % q))
     elif F.is_conway():
@@ -1734,6 +1736,7 @@ def gfq_gap_to_sage(x, F):
         raise ValueError('%r is not prime or defined by a Conway polynomial' % F)
     return g**e
 
+
 def intmod_gap_to_sage(x):
     r"""
     INPUT:
@@ -1837,5 +1840,5 @@ def gap_console():
     if not get_display_manager().is_in_terminal():
         raise RuntimeError('Can use the console only in the terminal. Try %%gap magics instead.')
     cmd, _ = gap_command(use_workspace_cache=False)
-    cmd += ' ' + os.path.join(SAGE_EXTCODE,'gap','console.g')
+    cmd += ' ' + os.path.join(SAGE_EXTCODE, 'gap', 'console.g')
     os.system(cmd)