September 2013
Intermediate to advanced
548 pages
12h 25m
English
Content preview from Programming Erlang, 2nd Edition
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Macros
Erlang macros are written as shown here:
| | -define(Constant, Replacement). |
| | -define(Func(Var1, Var2,.., Var), Replacement). |
Macros are expanded by the Erlang preprocessor epp when
an expression of the form ?MacroName is encountered.
Variables occurring in the macro definition match complete forms in the
corresponding site of the macro call.
| | -define(macro1(X, Y), {a, X, Y}). |
| | |
| | foo(A) -> |
| | ?macro1(A+10, b) |
That expands into this:
| | foo(A) -> |
| | {a,A+10,b}. |
In addition, a number of predefined macros provide information about the current module. They are as follows:
-
?FILEexpands to the current filename. -
?MODULEexpands to the current module name. -
?LINEexpands to the current line number.
Control Flow in Macros
Inside a module, the following ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.