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"opening" record types
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| Date: | -- (:) |
| From: | Yitzhak Mandelbaum <yitzhak@r...> |
| Subject: | "opening" record types |
Hi,
I'm generally averse to opening modules, as I find it can make it
hard to figure out where definitions are coming from. Instead, I
prefer to bind only those pieces of the module that I need, and to do
so explicitly. However, there is one instance in which I find myself
with little choice: record types. In order to bind the field-
constructors for a record, you need to copy the entire type from the
module in which its declared. For example,
module Foo =
struct
type t = {a: int; b:int}
end
without copying the type:
let y = {Foo.a=3; Foo.b=4}
with copying:
type t = Foo.t = {a: int; b:int}
let x = {a=3; b=4}
While this is a nuisance to begin with, its even worse if the record
type is subject to change -- each time it changes, you need to update
every place where you copied the definition.
Is there any way around this? That is, is there any way to use the
field names of a record defined in another module without opening the
whole module or copying the whole definition of the record.
Cheers,
Yitzhak
--------------------------------------------------
Yitzhak Mandelbaum
AT&T Labs - Research
http://www.research.att.com/~yitzhak