First-class environments. Discuss. ;)

#1

Post by swah » Wed, Jun 22, 2011, 12:37 PM UTC

First-class environments. Discuss. ;)
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Re: First-class environments. Discuss. ;)

#2

Post by croddin » Wed, Jun 22, 2011, 3:05 PM UTC

I always though it would be cool for a language have a special array-like object called 'scope'. To test if a variable was in scope you would say something like "if 'a' in scope:". It could also be useful in debugging. You could definitely abuse it, like global variables or Javascript's arguments.caller, but with great power comes great responsibility.

Re: First-class environments. Discuss. ;)

#3

Post by MauriceFlanagan » Wed, Jun 22, 2011, 3:39 PM UTC

croddin wrote: post #2

I always though it would be cool for a language have a special array-like object called 'scope'. To test if a variable was in scope you would say something like "if 'a' in scope:". It could also be useful in debugging. You could definitely abuse it, like global variables or Javascript's arguments.caller, but with great power comes great responsibility.

Would Python 'locals' be something like that?

  def f():
    x = 1
    if 'x' in locals():
      print 'x in scope'
  
  f()
  x in scope

Re: First-class environments. Discuss. ;)

#4

Post by bmm6o » Wed, Jun 22, 2011, 4:05 PM UTC

croddin wrote: post #2

I always though it would be cool for a language have a special array-like object called 'scope'. To test if a variable was in scope you would say something like "if 'a' in scope:". It could also be useful in debugging. You could definitely abuse it, like global variables or Javascript's arguments.caller, but with great power comes great responsibility.

What's the use case? Isn't this something the compiler can determine statically?

Re: First-class environments. Discuss. ;)

#5

Post by burgerbrain » Wed, Jun 22, 2011, 4:50 PM UTC

bmm6o wrote: post #4

croddin wrote: post #2

I always though it would be cool for a language have a special array-like object called 'scope'. To test if a variable was in scope you would say something like "if 'a' in scope:". It could also be useful in debugging. You could definitely abuse it, like global variables or Javascript's arguments.caller, but with great power comes great responsibility.

What's the use case? Isn't this something the compiler can determine statically?

You could potentially manually/dynamicaly manipulate the environment to an advantage.