
I'd like to redefine (++) so that it works on a more general class of "lists" (ListOf a). To do this, I found that I can import the Prelude hiding the definition of (++). Then I want to make [] an instance of ListOf, and have the (++) function call the built-in Prelude.(++). My problem is that I can't figure out how to call the built-in function. Just using "Prelude.(++)" doesn't seem to work in the way that "Prelude.foldl" would (for example). Any ideas? Terry

Did you try (Prelude.++)? I think that's the way it needs to be done.
Dan
On Thu, Sep 24, 2009 at 8:59 PM, Terry Hayes
I'd like to redefine (++) so that it works on a more general class of "lists" (ListOf a). To do this, I found that I can import the Prelude hiding the definition of (++). Then I want to make [] an instance of ListOf, and have the (++) function call the built-in Prelude.(++).
My problem is that I can't figure out how to call the built-in function. Just using "Prelude.(++)" doesn't seem to work in the way that "Prelude.foldl" would (for example).
Any ideas?
Terry
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Thanks, you got me to head in the correct direction.
I need to import Prelude twice, once without (++) and once qualified only for the (++) function.
import Prelude hiding ( (++) )
import qualified Prelude ( (++) )
Terry
________________________________
From: Daniel Peebles
I'd like to redefine (++) so that it works on a more general class of "lists" (ListOf a). To do this, I found that I can import the Prelude hiding the definition of (++). Then I want to make [] an instance of ListOf, and have the (++) function call the built-in Prelude.(++).
My problem is that I can't figure out how to call the built-in function. Just using "Prelude.(++)" doesn't seem to work in the way that "Prelude.foldl" would (for example).
Any ideas?
Terry
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participants (2)
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Daniel Peebles
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Terry Hayes