clearing GHCi (and, by extension, hint) loaded module dependencies

Alex Suraci at
Fri Sep 17 22:03:53 EDT 2010

Context: My language uses hint to interpret Haskell code at runtime, via `load: "path/to/file.hs"`. Hint works similar to ":load foo.hs" in GHCi (it uses the GHC API). After the source is interpreted the module's `load` function is executed in the language's VM. There is no valuable result; it is executed for its side-effects, usually definitions.

Problem: Around 80MB[1] is used up by the module's dependencies and never freed. Subsequent "load:"s are faster, but that 80MB overhead can be expensive on things like VPSes.

This can be simulated in GHCi by doing ":load foo.hs" followed by a ":load" to clear the loaded modules; the memory usage doesn't go down (understandably, in this case), and :loading it again is much faster.

Is there any way to "hard reset" or free the memory being used for the loaded module's dependencies?


[1]: number determined by loading an "empty" script, i.e. `load = return ()`

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