The GHC stage restriction is an error invoked when some Template Haskell
[1] construct requires the evaluation of run-time values at compile time. I
am going out on a limb and assuming that same code probably works in GHCI
because the interpreter does not have a discrete compile-time phase.
I assume that MinHeap is templated, but exactly how I do not know. Maybe
someone who is more familiar with Data.Heap will have an answer.
[1] http://www.haskell.org/haskellwiki/Template_Haskell
On Mon, Jan 7, 2013 at 10:03 PM, Martin Drautzburg wrote: When I :load this into ghci import Data.Heap heap = empty :: MinHeap (Int,String)
insert (1,"kjh") heap I get GHC stage restriction: `heap'
is used in a top-level splice or annotation,
and must be imported, not defined locally
In the second argument of `insert', namely `heap'
In the expression: insert (1, "kjh") heap But when I type in import Data.Heap let heap = empty :: MinHeap (Int,String)
insert (1,"kjh") heap everything works and I get fromList [(1,"kjh")] Why is that so and what can I do to prevent the "stage restriction"?
--
Martin _______________________________________________
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