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What is a Context Free Grammar?
...y and then the Wikipedia entry on formal grammar, I am left utterly and totally befuddled. Would someone be so kind as to explain what these things are?
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Get MD5 hash of big files in Python
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@Boris, you can't actually say that BLAKE2 is secure. All you can say is that it hasn't been broken yet.
– vy32
Apr 8 at 14:57
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Which would be better for concurrent tasks on node.js? Fibers? Web-workers? or Threads?
...e to use is a confusion and one of them definitely needs to be used - afterall what's the purpose of having a server which is just good at IO and nothing else? Suggestions needed!
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Display open transactions in MySQL
...ction to the server while sending a statement, it immediately and automatically tries to reconnect once to the server and send the statement again. However, even if mysql succeeds in reconnecting, your first connection has ended and all your previous session objects and settings are lost: temporary ...
NHibernate ISession Flush: Where and when to use it, and why?
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Briefly:
Always use transactions
Don't use Close(), instead wrap your calls on an ISession inside a using statement or manage the lifecycle of your ISession somewhere else.
From the documentation:
From time to time the ISession will execute the SQL statements needed to synchronize the ADO.NET ...
How to migrate GIT repository from one server to a new one
...n push the content to the new location
git push new_repo_name master
Finally remove the old one
git remote rm origin
After that you can do what bdonlan said and edit the.git/config file to change the new_repo_name to origin. If you don't remove the origin (original remote repository), you can ...
Custom views with Storyboard
...complex screens (View Controllers) I used to separate the whole thing in smaller pieces (I call them widgets). These widgets consist basically of a MyWidget.h and a MyWidget.m file as well as a MyWidget.xib file, where the root element is a UIView and the MyWidget class is the File Owner of ...
T-SQL: Opposite to string concatenation - how to split string into multiple records [duplicate]
...s(pn, start, stop) AS (
SELECT 1, 1, CHARINDEX(@sep, @s)
UNION ALL
SELECT pn + 1, stop + 1, CHARINDEX(@sep, @s, stop + 1)
FROM Pieces
WHERE stop > 0
)
SELECT pn,
SUBSTRING(@s, start, CASE WHEN stop > 0 THEN stop-start ELSE 512 END) AS s
FROM Piec...
Equivalent of varchar(max) in MySQL?
... includes a byte or two to encode the length of a given string. So you actually can't declare a varchar of the maximum row size, even if it's the only column in the table.
mysql> CREATE TABLE foo ( v VARCHAR(65534) );
ERROR 1118 (42000): Row size too large. The maximum row size for the used tabl...
Catching error codes in a shell pipe
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If you really don't want the second command to proceed until the first is known to be successful, then you probably need to use temporary files. The simple version of that is:
tmp=${TMPDIR:-/tmp}/mine.$$
if ./a > $tmp.1
then
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