TODO
====
A non-exhaustive list of things TO DO for Extrapolate.
cleanup
-------
* `renames1`:
rename show functions:
- move `showCE` to `Core`;
- add and use `Core.showCCE`;
- rename `IO.showCEC` to `IO.showCEandGens`;
* `renames2`:
rename counterexamples:
- rename `counterExamples*` to `counterExamples*E`;
- add `counterExamples* :: ... String ...`;
* `cleanup`:
cleanup and remove unused functions, like `showCEG`;
thighten exports, removing uneeded functions (`backgroundWith`).
examples
--------
* `add-redblack-eg`:
add the redblacktree example from Small/SmartCheck/Okasaki.
see `ideal-generalization`.
Also described on: http://matt.might.net/articles/quick-quickcheck/
It has been added, but cannot generalize the counter-examples found: during
generalization, the very exceptions that cause the error, make the
generalization fail. Somehow catch those errors on generalization.
* `ideal-generalizations`:
Add examples of ideal generalizations as described in past paper by human
experts. The counter example is `blah` because the property fails for every
`bleh` and `blih`. I found:
- one on Duregard's licentiate Thesis: `prop_cycle` from `BNFC-meta`.
- one on Duregard's doctorate Thesis.
- one on SmallCheck's paper: `prop_insertRB` from RedBlack
there are none on:
- QuickCheck
- Testing and Tracing with Quickcheck and Hat
- SmartCheck
- Feat
- Real World Haskell
- Learn-you-a-haskell
- Growing and shrinking polygons
- QuickFuzz
* `add-th-eg`:
add the parser example from the Feat paper;
* `apply-lazysmallcheck`:
apply Lazy SmallCheck to calculator and parse and record the results.
feature
-------
* `report-multiple-generalizations`:
when there is more than one generalization and they don't encompass
one-another, report both.
* `detect-silly-conditionals`:
eg:
xs when 0 /= length xs
that's just:
_:_
the above is for the last property of the list example
* `add-derive-tests`:
add tests of derivation;
* `show-and-expr-display`:
display counterExamples both as Show and Expr, I don't know how easy is to
use show since counterExamples are represented as Exprs, I don't think I can
eval because I am not bound in a type context.
* `renaming`:
possibly print `(Div (C 0) (Add (C x) (C (negate x))))`
which is equivalent to `(Div (C 0) (Add (C x) (C y))) when y == negate x`
instead of `(Div (C 0) (Add (C 0) (C 0)))`;
I got it to print the middle one, by just: `-- not (isAssignment wc)` and
`constant "negate" (negate -:> x) in the background`.
* `improve-record-printing`:
Improve the record printing by explictly printing records and _not_ showing
variables. For example, when testing `prop_delete`, currently we get:
StackSet (Screen (Workspace x y (Just s)) z x’) ss ws crs
but we could get instead, with the actual following indentation:
> check prop_delete
StackSet { current = Screen
{ workspace = Workspace
{ tag = x
, layout = y
, stack = Just s
}
, screen = z
, screenDetail = x'
}
, visible = ss
, hidden = ws
, floating = crs
}
which could be further summarized to:
stackset {current = scr {workspace = ws {stack = Just s}}}
performance and improvements in the algorithm (only later)
----------------------------------------------------------
* `type-after-type`:
to improve performance, instead of working with all types at once, perform
the algorithm type after type
* `single-then-multi`:
only do vassignments *after* finding a failing single variable instance.
I'll have to re-test, but the time I save may pay off.
* `no-listable-tuples`:
there is no need to include listable tuples in the instances list (or at
least no need to use it). Instead of having `xy` we would get `(x,y)`.
However, maybe it is fine as it is.
won't fix
---------
* `nlp-example`:
add the NLP example from the SmartCheck paper. I don't think I'll use this
because of a few issues.
GenI has the bit-rot:
- GenI 0.24.3 refuses to build on GHC 8.0.1;
- GenI 0.24.3 builds on GHC 7.8 but test files are missing;
- The version on git is the most up-to-date contradicting the fact that it is
supposed to be a mirror from Darcs. It does not seem to be building on
Travis. It has tests, but I have not tried compiling it.
Lee Pike's paper does not list the exact property and fault for which
SmartCheck recuces its counterexample. I also looked at the TeX comments,
and the info is also not there. The mentioned stackoverflow question does
not help with that either. I could certainly ask of course if I choose to
carry on with this.
Thinking again, maybe it is a good idea to use this. It is a real library
with real bugs in the git history.