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How to intercept touches events on a MKMapView or UIWebView objects?
...lot of hackish programming that imperfectly duplicates Apple's code, especially in the case of multitouch.
Here's what I do: Implement a gesture recognizer that cannot be prevented and that cannot prevent other gesture recognizers. Add it to the map view, and then use the gestureRecognizer's touc...
Can someone explain the traverse function in Haskell?
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traverse is the same as fmap, except that it also allows you to run effects while you're rebuilding the data structure.
Take a look at the example from the Data.Traversable documentation.
data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)
The Functor instance of Tr...
Object reference not set to an instance of an object.Why doesn't .NET show which object is `null`?
...ull
IL_0002: stloc.0 // s
IL_0003: ldloc.0 // s
IL_0004: callvirt System.String.get_Length
IL_0009: call System.Console.WriteLine
It is the callvirt opcode that throws the NullReferenceException and it does that when the first argument on the evaluation stack is a null ...
Determine if Python is running inside virtualenv
...r sys.base_prefix did not ever exist. So a fully robust check that handles all of these cases could look like this:
import sys
def get_base_prefix_compat():
"""Get base/real prefix, or sys.prefix if there is none."""
return getattr(sys, "base_prefix", None) or getattr(sys, "real_prefix", No...
/bin/sh: pushd: not found
...d by child processes. (A hypothetical pushd command might do the chdir(2) call and then start a new shell, but ... it wouldn't be very usable.) pushd is a shell builtin, just like cd.
So, either change your script to start with #!/bin/bash or store the current working directory in a variable, do yo...
Is it possible to GROUP BY multiple columns using MySQL?
...garding SUM using with GROUP BY. If GROUP BY only by one column, then SUMs all values of each distinct (different) the column value sqlfiddle.com/#!9/1cbde2/2. If GROUP BY two columns. Then mysql at first checks if for the first column value there are different values in the second column. If yes, t...
Naming cookies - best practices [closed]
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@Emanuil: To distinguish it from all the other cookies generated by other apps on the same domain.
– Ignacio Vazquez-Abrams
Sep 19 '12 at 20:50
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Can I have an IF block in DOS batch file?
...t, and the opening parenthesis.
I am setting @echo off to keep from seeing all of the statements printed to the console as they execute, and instead just see the output of those that specifically begin with echo.
I'm using the built-in ERRORLEVEL variable just as a test. Read more here
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What is the meaning of “… …” token? i.e. double ellipsis operator on parameter pack
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– Johannes Schaub - litb
Apr 11 '11 at 20:15
2
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When to use ' (or quote) in Lisp?
...al operator (quote) (or equivalent ' ) function does, yet this has been all over Lisp code that I've seen.
10 Answers
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