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How does the Windows Command Interpreter (CMD.EXE) parse scripts?
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We performed experiments to investigate the grammar of batch scripts. We also investigated differences between batch and command line mode.
Batch Line Parser:
Here is a brief overview of phases in the batch file line parser:
Phas...
Regex to match a digit two or four times
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There's no specific syntax for that, but there are lots of ways to do it:
(?:\d{4}|\d{2}) <-- alternation: four digits or two
\d{2}(?:\d{2})? <-- two digits, and optionally two more
(?:\d{2}){1,2} <-- two digits, times one or two
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What do all of Scala's symbolic operators mean?
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I divide the operators, for the purpose of teaching, into four categories:
Keywords/reserved symbols
Automatically imported methods
Common methods
Syntactic sugars/composition
It is fortunate, then, that most categories are represented in t...
Difference between return and exit in Bash functions
...that of the last command executed. A trap on EXIT is executed before the shell terminates.
EDIT:
As per your edit of the question, regarding exit codes, return has nothing to do with exit codes. Exit codes are intended for applications/scripts, not functions. So in this regard, the only...
Python Infinity - Any caveats?
...ic involving inf:
>>> 0 * float("inf")
nan
Note that you will normally not get an inf value through usual arithmetic calculations:
>>> 2.0**2
4.0
>>> _**2
16.0
>>> _**2
256.0
>>> _**2
65536.0
>>> _**2
4294967296.0
>>> _**2
1.84467440...
Mathematical functions in Swift
How do I use mathematical functions like sqrt() , floor() , round() , sin() , etc?
6 Answers
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Is char signed or unsigned by default?
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The book is wrong. The standard does not specify if plain char is signed or unsigned.
In fact, the standard defines three distinct types: char, signed char, and unsigned char. If you #include <limits.h> and then look at CHAR_MIN, you can find out if plain char is signed or unsigned (if CHA...
Django filter versus get for single object?
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get() is provided specifically for this case. Use it.
Option 2 is almost precisely how the get() method is actually implemented in Django, so there should be no "performance" difference (and the fact that you're thinking about it indicates you're violating...
Convert JavaScript string in dot notation into an object reference
...'m flattered that this answer has gotten many upvotes, I am also somewhat horrified. If one needs to convert dot-notation strings like "x.a.b.c" into references, it could (maybe) be a sign that there is something very wrong going on (unless maybe you're performing some strange deserialization).
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How does Java handle integer underflows and overflows and how would you check for it?
...back to the maximum value and continues from there.
You can check that beforehand as follows:
public static boolean willAdditionOverflow(int left, int right) {
if (right < 0 && right != Integer.MIN_VALUE) {
return willSubtractionOverflow(left, -right);
} else {
r...