[erlang-questions] [Erlang]about "apply" function in the erlang.erl

Masklinn <>
Tue May 17 10:18:50 CEST 2011


On 2011-05-17, at 09:51 , Bengt Kleberg wrote:
> Greetings,
> 
> apply is a built in function (BIF). It is implemented in C, not Erlang.
Does it work in a similar manner to that of Smalltalks, or differently?

In Smalltalks, `Boolean ifTrue: aBlock ifFalse: aBlock` literal forms
are usually compiled to call into native code directly, so the
implementation of this message in Smalltalk code in Smalltalk VMs looks
like this:

    ifTrue:trueBlock ifFalse:falseBlock
        ^self ifTrue:[ trueBlock call ] ifFalse: [ falseBlock call ]

which looks like it would not work, but when the form
`var ifTrue:aBlockLiteral ifFalse:aBlockLiteral` is encountered the
Smalltalk compiler takes over and replaces this with native code. So the
Smalltalk implementation is only ever hit for non-literal sends (either
non-literal blocks, or usage of selectors), and its only role is to
redirect execution to the native version.

Is the purpose (and behavior) of the pure version of erlang:apply
similar?



More information about the erlang-questions mailing list