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Re: Functional Programming needs some real world use cases

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Stefan Ram wrote:
> Scott Sauyet writes:

>> key tenets of functional programming is that code must be referentially
>> transparent.  This means that any expression could be replaced with its
>> value with no change to the behavior of the system.
> 
>   »2« is an example of an expression. An expression is part of the
>   source code.
> 
>   A value is abstract, it is not source text like an expression.
> 
>   Therefore, an expression cannot be replaced by a value in the source
>   code.

Have you been hanging out with the pedants again?

"an expression could be replaced with a representation of its value with 
no change to the behavior of the system."  Does that satisfy you?



>   An expression, however, can be replaced by another expression equal in
>   value. If this can be done without changing the meaning of a program
>   it is what Søndergaard and Sestof call »substitutivity of identity«.
>   [ ... ]

Thank you for that reference.  I had not read their paper although I'd 
read many of their sources, including Landin, Strachey, and even Quine (I 
just knew that philosophy course would come in handy!)  I never quite 
made it through the _Principia_ (ok, I never quite made it through the 
first 20 pages of the _Principia_; I bore easily!) But I find the meaning 
as commonly used in computing perfectly reasonable, and don't need to go 
back to Quine to infer a deeper meaning for the phrase/


>   Other concepts that sometimes are used as definitions of »referential
>   transparency« are extensionality, definiteness and unfoldability, all
>   independed properties! See also
> 
> http://www.purl.org/stefan_ram/pub/referential_transparency


Sure, but I think that for most of us, the definition above has come to 
dominate the alternatives.  At least for the uses in computer science.  I 
know nothing about linguistics or the other such places.

  -- Scott

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Functional Programming needs some real world use cases justaguy <lichunshen84@gmail.com> - 2017-01-18 20:09 -0800
  Re: Functional Programming needs some real world use cases Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-19 20:10 +0000
    Re: Functional Programming needs some real world use cases Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-19 21:16 +0100
      Re: Functional Programming needs some real world use cases Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-19 21:24 +0000
    Re: Functional Programming needs some real world use cases justaguy <lichunshen84@gmail.com> - 2017-01-19 12:34 -0800
      Re: Functional Programming needs some real world use cases justaguy <lichunshen84@gmail.com> - 2017-01-19 12:41 -0800
        Re: Functional Programming needs some real world use cases justaguy <lichunshen84@gmail.com> - 2017-01-19 13:01 -0800
          Re: Functional Programming needs some real world use cases justaguy <lichunshen84@gmail.com> - 2017-01-19 17:26 -0800
    Re: Functional Programming needs some real world use cases Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-19 21:23 +0000
      Re: Functional Programming needs some real world use cases Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-19 21:50 +0000
    Re: [Firefox]"print" Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-24 01:52 +0100
      Re: [Firefox]"print" Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-24 05:45 +0100
  Re: Functional Programming needs some real world use cases Scott Sauyet <scott@sauyet.com> - 2017-01-20 04:28 +0000
    Re: Functional Programming needs some real world use cases justaguy <lichunshen84@gmail.com> - 2017-01-19 21:18 -0800
    Re: Functional Programming needs some real world use cases John Harris <niam@jghnorth.org.uk.invalid> - 2017-01-20 10:22 +0000
      Re: Functional Programming needs some real world use cases Scott Sauyet <scott@sauyet.com> - 2017-01-21 01:29 +0000
    Re: Functional Programming needs some real world use cases Scott Sauyet <scott@sauyet.com> - 2017-01-21 01:15 +0000
    Re: Functional Programming needs some real world use cases "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-01-21 15:00 -0800
  Re: Functional Programming needs some real world use cases Scott Sauyet <scott@sauyet.com> - 2017-01-20 05:00 +0000
  Re: Functional Programming needs some real world use cases Scott Sauyet <scott@sauyet.com> - 2017-01-20 05:02 +0000

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