"Concurrent Programming in Erlang" (Second Edition) Query

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"Concurrent Programming in Erlang" (Second Edition) Query

John Duffy
Hi

I'm learning Erlang with the help of "Concurrent Programming in Erlang" (Second Edition). Being an electrical engineer, I'm a bit stumped by the computer science terminology of the last paragraph of 2.3 Expression Evaluation:

"The evaluator can be thought of as function E which reduces an expression to a ground term:  ... <E examples> ... where APPLY represents a function which applies a function to its arguments".

If there is someone who has this book and can translate this paragraph and the examples into simple engineer speak I would be very grateful.

Kind regards

John 

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Re: "Concurrent Programming in Erlang" (Second Edition) Query

Luke
Eval/Apply is a concept taken from Lisp

https://mitpress.mit.edu/sicp/full-text/sicp/book/node77.html


Essentially, eval "executes" or "runs" S-expressions which then return/evaluate-to something - maybe a number, maybe a string, maybe a function. Apply means to apply a function to a list of parameters (or in slightly different wording, run a function with some parameters). The execution of a function program can be thought of as one continuous cycle of eval/apply, for example we can eval some expression which results in a function, this function then gets applied to some parameters, some of which may themselves have been expressions we have already evaluated.


On Fri, Dec 15, 2017 at 9:46 AM, John Duffy <[hidden email]> wrote:
Hi

I'm learning Erlang with the help of "Concurrent Programming in Erlang" (Second Edition). Being an electrical engineer, I'm a bit stumped by the computer science terminology of the last paragraph of 2.3 Expression Evaluation:

"The evaluator can be thought of as function E which reduces an expression to a ground term:  ... <E examples> ... where APPLY represents a function which applies a function to its arguments".

If there is someone who has this book and can translate this paragraph and the examples into simple engineer speak I would be very grateful.

Kind regards

John 

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[hidden email]
http://erlang.org/mailman/listinfo/erlang-questions



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