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Variables bind once in Erlang


Variables bind once in Erlang

By : Guillermo
Date : November 19 2020, 01:01 AM
seems to work fine Your second receive X -> X end. already has X bound; it is attempting to receive a message exactly matching the one you already saw. Since the pid is going to be different, the message will never match. So it hangs, waiting for one that does match.
You need to f(X) first.
code :


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Re-using my variables in Erlang Code, not Erlang Shell

Re-using my variables in Erlang Code, not Erlang Shell


By : Harte
Date : March 29 2020, 07:55 AM
hope this fix your issue The REPL shell is interpreted, the code file is compiled. The shell comes in handy to test things, but you would not write your web server in a shell. ;-)
It would be possible and not even difficult for the Erlang hackers to implement an f(V) language construct, but it would not fit the Erlang design model. Mind, no function could accomplish the forgetting of a variable, so it had to be done in a new native language construct. When compiled, the virtual machine does not know the variables anymore, as Erlang is run by a rather ordinary stack machine, not much different from the JVM.
Anonymous variables in Erlang

Anonymous variables in Erlang


By : LiangJ
Date : March 29 2020, 07:55 AM
it helps some times The don't care variable _ is a VERY SPECIAL variable which matches anything and is NEVER bound to a value. It is used when I know there is something there but I don't care what the value is and I will never use. Seeing _ is never bound it can not be used in an expression and the compiler flags it as an error.
Variables like _Var are perfectly normal variables which you can match against and will be bound to values which means they can be used in expressions. Prefixing a variable with _ is about intent. The compiler normally warns you about a variable which is bound in a pattern but is never used, often a sign of an error. But the compiler does not warn for variables prefixed with _ like in _Var. The intent being that I want to give the variable a name, naming things is good, but that I know I will never use it.
Variables in Erlang

Variables in Erlang


By : tcmedia
Date : March 29 2020, 07:55 AM
it should still fix some issue FallVelocity refers to a function. Then you are calling FallVelocity a couple of times with different parameters. And of course, each different invocation of FallVelocity will yield a different result.
The result of each invocation of FallVelocity isn't assigned to FallVelocity var. The purpose of FallVelocity is to refer to a function, not to the result of the invocation of that function.
code :
3> Hoohaa = FallVelocity(20). %% This is ok
   19.79898987322333

4> Hoohaa = FallVelocity(200). %% Nope, it will fail
Erlang - Write a pattern that will bind a variable to the second element in this tuple {<0.206.0>, {rect, 10, 30}}

Erlang - Write a pattern that will bind a variable to the second element in this tuple {<0.206.0>, {rect, 10, 30}}


By : user3889740
Date : March 29 2020, 07:55 AM
will be helpful for those in need How do I write a pattern that will bind a variable to the second element in this tuple {<0.206.0>, {rect, 10, 30}}? , As simple as this...
How does an Erlang process bind to a specific scheduler?

How does an Erlang process bind to a specific scheduler?


By : Constance LI
Date : March 29 2020, 07:55 AM
like below fixes the issue Currently processes does not get bound to specific schedulers (though you can force it via undocumentet functions, not recommended). Scheduler threads may be bound to logical processors using cpu topology and binding types. The vm does use some of this information to enhance performance in its normal scheduling scheme.
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