Since I started learning Objective-C and Cocoa, I've been wondering why they have chosen the extension .m for the implementation files - was it supposed to mean something, or was it just a random letter?
3 Answers
Today most people would refer to them as "method files", but
"The .m extension originally stood for "messages" when Objective-C was first introduced, referring to a central feature of Objective-C [...]"
(from the book "Learn Objective-C on the Mac" by Mark Dalrymple and Scott Knaster, page 9)
EDIT: To satisfy an itch I emailed Brad Cox, the inventor of Objective-C, about the question and he answered with this single line:
"Because .o and .c were taken. Simple as that."
Here's the email as visual proof:
3 Comments
ThomasW
Brad Cox, RIP. en.wikipedia.org/wiki/Brad_Cox
Usukhbayar Batbayar
What about .oc? Surely it doesn't have to be a single letter, right?
Usukhbayar Batbayar
Seems it's also taken.
It stands for "methods". From the comp.lang.objective-C FAQ:
The organisation of Objective-C source is typically similar to that of C or C++ source code, with declarations and object interfaces going into header files named with a .h extension, and definitions and object implementations going in files named with a .m (short for methods) extension.
answered Mar 16, 2009 at 22:03
Adam Rosenfield
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Comments
.m files contain the (m)ethods. Possible reason?
1 Comment
NeverStopLearning
m files might contain (m)ultitude of comments as well! go figure:)
.mfiles are implementation files as you said. Knowing Apple likes to prefix everything withiit is easy to see that implementation becomes mplementation without saidi. Then they just used the first letter of mplementation for the file extension:m.