Closes #980: fix DeprecationWarnings (mostly due to files closed by __del__) on Py3.

Also fix a bunch of other uses of open() to use the with statement.

7 files changed, 34 insertions, 56 deletions

diff --git a/pygments/cmdline.py b/pygments/cmdline.py
index 7c23ebee..035f8c87 100644
--- a/pygments/cmdline.py
+++ b/pygments/cmdline.py
@@ -371,7 +371,8 @@ def main(args=sys.argv):
 
         infn = args[0]
         try:
-            code = open(infn, 'rb').read()
+            with open(infn, 'rb') as infp:
+                code = infp.read()
         except Exception as err:
             print('Error: cannot read infile:', err, file=sys.stderr)
             return 1
diff --git a/pygments/formatters/_mapping.py b/pygments/formatters/_mapping.py
index 1a083904..d4aeaeb0 100755
--- a/pygments/formatters/_mapping.py
+++ b/pygments/formatters/_mapping.py
@@ -62,19 +62,15 @@ if __name__ == '__main__':
     found_formatters.sort()
 
     # extract useful sourcecode from this file
-    f = open(__file__)
-    try:
-        content = f.read()
-    finally:
-        f.close()
+    with open(__file__) as fp:
+        content = fp.read()
     header = content[:content.find('FORMATTERS = {')]
     footer = content[content.find("if __name__ == '__main__':"):]
 
     # write new file
-    f = open(__file__, 'w')
-    f.write(header)
-    f.write('FORMATTERS = {\n    %s\n}\n\n' % ',\n    '.join(found_formatters))
-    f.write(footer)
-    f.close()
+    with open(__file__, 'w') as fp:
+        fp.write(header)
+        fp.write('FORMATTERS = {\n    %s\n}\n\n' % ',\n    '.join(found_formatters))
+        fp.write(footer)
 
     print ('=== %d formatters processed.' % len(found_formatters))
diff --git a/pygments/lexers/_lua_builtins.py b/pygments/lexers/_lua_builtins.py
index 0519c6cb..79a8da62 100644
--- a/pygments/lexers/_lua_builtins.py
+++ b/pygments/lexers/_lua_builtins.py
@@ -221,21 +221,17 @@ if __name__ == '__main__':
             return 'basic'
 
     def regenerate(filename, modules):
-        f = open(filename)
-        try:
-            content = f.read()
-        finally:
-            f.close()
+        with open(filename) as fp:
+            content = fp.read()
 
         header = content[:content.find('MODULES = {')]
         footer = content[content.find("if __name__ == '__main__':"):]
 
 
-        f = open(filename, 'w')
-        f.write(header)
-        f.write('MODULES = %s\n\n' % pprint.pformat(modules))
-        f.write(footer)
-        f.close()
+        with open(filename, 'w') as fp:
+            fp.write(header)
+            fp.write('MODULES = %s\n\n' % pprint.pformat(modules))
+            fp.write(footer)
 
     def run():
         version = get_newest_version()
diff --git a/pygments/lexers/_mapping.py b/pygments/lexers/_mapping.py
index a714941b..80b4da4a 100644
--- a/pygments/lexers/_mapping.py
+++ b/pygments/lexers/_mapping.py
@@ -388,19 +388,15 @@ if __name__ == '__main__':
     found_lexers.sort()
 
     # extract useful sourcecode from this file
-    f = open(__file__)
-    try:
-        content = f.read()
-    finally:
-        f.close()
+    with open(__file__) as fp:
+        content = fp.read()
     header = content[:content.find('LEXERS = {')]
     footer = content[content.find("if __name__ == '__main__':"):]
 
     # write new file
-    f = open(__file__, 'w')
-    f.write(header)
-    f.write('LEXERS = {\n    %s,\n}\n\n' % ',\n    '.join(found_lexers))
-    f.write(footer)
-    f.close()
+    with open(__file__, 'w') as fp:
+        fp.write(header)
+        fp.write('LEXERS = {\n    %s,\n}\n\n' % ',\n    '.join(found_lexers))
+        fp.write(footer)
 
     print ('=== %d lexers processed.' % len(found_lexers))
diff --git a/pygments/lexers/_php_builtins.py b/pygments/lexers/_php_builtins.py
index 1e04cfc0..343b4416 100644
--- a/pygments/lexers/_php_builtins.py
+++ b/pygments/lexers/_php_builtins.py
@@ -4733,20 +4733,16 @@ if __name__ == '__main__':
         os.remove(download[0])
 
     def regenerate(filename, modules):
-        f = open(filename)
-        try:
-            content = f.read()
-        finally:
-            f.close()
+        with open(filename) as fp:
+            content = fp.read()
 
         header = content[:content.find('MODULES = {')]
         footer = content[content.find("if __name__ == '__main__':"):]
 
-        f = open(filename, 'w')
-        f.write(header)
-        f.write('MODULES = %s\n\n' % pprint.pformat(modules))
-        f.write(footer)
-        f.close()
+        with open(filename, 'w') as fp:
+            fp.write(header)
+            fp.write('MODULES = %s\n\n' % pprint.pformat(modules))
+            fp.write(footer)
 
     def run():
         print('>> Downloading Function Index')
diff --git a/pygments/lexers/_sourcemod_builtins.py b/pygments/lexers/_sourcemod_builtins.py
index 8ef6cbef..40ef5299 100644
--- a/pygments/lexers/_sourcemod_builtins.py
+++ b/pygments/lexers/_sourcemod_builtins.py
@@ -1132,21 +1132,17 @@ if __name__ == '__main__':
         return functions
 
     def regenerate(filename, natives):
-        f = open(filename)
-        try:
-            content = f.read()
-        finally:
-            f.close()
+        with open(filename) as fp:
+            content = fp.read()
 
         header = content[:content.find('FUNCTIONS = (')]
         footer = content[content.find("if __name__ == '__main__':")-1:]
 
 
-        f = open(filename, 'w')
-        f.write(header)
-        f.write(format_lines('FUNCTIONS', natives))
-        f.write(footer)
-        f.close()
+        with open(filename, 'w') as fp:
+            fp.write(header)
+            fp.write(format_lines('FUNCTIONS', natives))
+            fp.write(footer)
 
     def run():
         version = get_version()
diff --git a/pygments/unistring.py b/pygments/unistring.py
index 3db3ae8e..c2a171dd 100644
--- a/pygments/unistring.py
+++ b/pygments/unistring.py
@@ -99,11 +99,8 @@ if __name__ == '__main__':
 
     categories = {}
 
-    f = open(__file__)
-    try:
-        content = f.read()
-    finally:
-        f.close()
+    with open(__file__) as fp:
+        content = fp.read()
 
     header = content[:content.find('Cc =')]
     footer = content[content.find("def combine("):]