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What exactly is Arel in Rails 3.0?
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What exactly is Arel in Rails 3.0?
It's an object model for an algebra of relational query operators.
I understand that it is a replacement for ActiveRecord
No, it isn't. It's a replacement for hand-crafting SQL queries in strings. It is a common query l...
What's the need of array with zero elements?
...lloc(sizeof(*var) + extra);
You can access var->data with indices in [0, extra). Note that sizeof(struct something) will only give the size accounting for the other variables, i.e. gives data a size of 0.
It may be interesting also to note how the standard actually gives examples of mallocin...
How to prevent gcc optimizing some statements in C?
...ready...
unsigned char *pageptr = ...;
((unsigned char volatile *)pageptr)[0] = pageptr[0];
The volatile type qualifier instructs the compiler to be strict about memory stores and loads. One purpose of volatile is to let the compiler know that the memory access has side effects, and therefore mus...
Gradient of n colors ranging from color 1 and color 2
...friend here:
colfunc <- colorRampPalette(c("black", "white"))
colfunc(10)
# [1] "#000000" "#1C1C1C" "#383838" "#555555" "#717171" "#8D8D8D" "#AAAAAA"
# [8] "#C6C6C6" "#E2E2E2" "#FFFFFF"
And just to show it works:
plot(rep(1,10),col=colfunc(10),pch=19,cex=3)
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What are the relationships between Any, AnyVal, AnyRef, Object and how do they map when used in Java
...red a primitive in Java is descendant from AnyVal in Scala. Until Scala 2.10.0, AnyVal was sealed, and programmers were unable to extend it. It should be interesting to see what will happen with Scala on .Net, since interoperability alone calls for Scala to at least recognize user-defined "primitive...
Get current value of a setting in Vim
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answered Jan 16 '10 at 17:28
JaredParJaredPar
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Ruby on Rails patterns - decorator vs presenter
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A decorator is more of a "let's add some functionality to this entity". A presenter is more of ...
Loop through Map in Groovy?
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edited Sep 19 '17 at 13:07
answered Apr 5 '12 at 23:23
Ja...
How to view revision history for Mercurial file?
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hg log file
hg diff -r 10 -r 20 file
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How can I rename a field for all documents in MongoDB?
Assuming I have a collection in MongoDB with 5000 records, each containing something similar to:
7 Answers
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