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What is a 'semantic predicate' in ANTLR?
...hing:
grammar Numbers;
// entry point of this parser: it parses an input string consisting of at least
// one number, optionally followed by zero or more comma's and numbers
parse
: number (',' number)* EOF
;
// matches a number that is between 1 and 3 digits long
number
: Digit Digit Di...
How to import an excel file in to a MySQL database
... to import spreadsheet data into a MySQL database that doesn't rely on any extra software. Let's assume you want to import your Excel table into the sales table of a MySQL database named mydatabase.
Select the relevant cells:
Paste into Mr. Data Converter and select the output as MySQL:
Change...
Python != operation vs “is not”
... but are not identical. (They are not the same object in memory.)
Example: Strings
>>> greeting = "It's a beautiful day in the neighbourhood."
>>> a = unicode(greeting)
>>> b = unicode(greeting)
>>> a is b
False
>>> a == b
True
Note: I use unicode stri...
What exactly is Arel in Rails 3.0?
...eRecord
No, it isn't. It's a replacement for hand-crafting SQL queries in strings. It is a common query layer that underlies ActiveRecord, but it can also be used as an underpinning for DataMapper, for example.
If it is a replacement for anything, it's a replacement for Ambition. Or, you can think ...
How can I force Powershell to return an array when a call only returns one object?
...ve a Count property. Single objects (scalar) do not have a Count property. Strings have a length property so you might get false results, use the Count property:
if (@($serverIps).Count -le 1)...
By the way, instead of using a wildcard that can also match strings, use the -as operator:
[array]$s...
Why should I use a pointer rather than the object itself?
...eir destructors called once they go out of scope. For example:
{
std::string s;
}
// s is destroyed here
On the other hand, if you use a pointer dynamically allocated, its destructor must be called manually. delete calls this destructor for you.
{
std::string* s = new std::string;
}
dele...
Why doesn't C have unsigned floats?
... same signed or unsigned -- floating point, not so much. Who would do the extra work to support both signed and unsigned floats given the relatively low marginal utility of such a feature?
– ephemient
Feb 5 '09 at 0:42
...
How to use unicode characters in Windows command line?
...egistry key HKEY_CURRENT_USER\Software\Microsoft\Command Processor and add String value Autorun = chcp 65001.
Or you can use this small Batch-Script for the most common code pages.
@ECHO off
SET ROOT_KEY="HKEY_CURRENT_USER"
FOR /f "skip=2 tokens=3" %%i in ('reg query HKEY_LOCAL_MACHINE\SYSTEM\C...
ASP.NET Identity DbContext confusion
...', 'IdentityRole', ...
public class ApplicationRole : IdentityRole<string, ApplicationUserRole>
{
public ApplicationRole()
{
this.Id = Guid.NewGuid().ToString();
}
public ApplicationRole(string name)
: this()
{
this.Name = name;
}
// ...
Automatic vertical scroll bar in WPF TextBlock?
...cyProperty.RegisterAttached(
"AppendText",
typeof (string),
typeof (TextBoxApppendBehaviors),
new UIPropertyMetadata(null, OnAppendTextChanged));
public static string GetAppendText(TextBox textBox)
{
return (string)textBox.GetValue(App...