Simon Marlow wrote:
On 04 March 2005 12:58, Keean Schupke wrote:
There can only be one top level module in ghci (there can only
be one module name before the '>' prompt - that modules options
should be in effect.
No, you can have multiple top-level module scopes in effect. See the GHCi documentation.
But I can also have just one top level module ...
But what if it is an application and not a library... you definitely do not wantr to have to explainSimon Marlow wrote:
I think GHC's behaviour is right here. To use the flag settings fromRequiring options on the command line exposes the implementation
the source module on the command-line would be wrong: for example,
when the module is compiled, its implementation (and therefore flag
settings) must be hidden.
I do not expect the GHCi user to be required to know which flags to
apply to get my code to run.
Why not? You're providing a library which exports some instances. If overlapping instance resolution is required to resolve overloading in code that uses the library, I want to know about it, and I don't want the compiler to turn on overlapping instance resolution behind my back.
in the user manual that ghci needs to be started with:
ghci -fglasgow-exts -fallow-overlapping-instances ...
Further more it is the _importing_ module that needs to have overlapping instances defined, therefore
there is absolutely no chance of them being turned on behind your back.
Importing a library should *not* affect how the code that imports it isIt would not... All I am saying is if the top level module in GHCi (the one named in the prompt)
compiled, except in the ways you expect (bringing names and instances
into scope).
has OPTIONS pagmas these should be in effect.
This worked in all GHCi before 6.4 - so something has broken the (in mu opinion) correctIf you could specify overlapping on a per-instance basis, then that would be a way around the problem.
behavior. Was this a deliberate decision - or has something just changed without anyone
realising?
Keean.
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