mumuki / mumuki-haskell-runner

mumuki-haskell-runner

Run the server

RACK_ENV=development rackup -p 4567

mumuki-haskell-runner's Issues

Haskell Console: Being able to use :t

From Issue mumuki/mumuki-laboratory#482

In GHCi, I can do:

Prelude> :t "hola"
"hola" :: [Char]

Yet in Mumuki console I get:

Prelude> :t "hola"
/tmp/compilation58:7:22: parse error on input ‘:’

Nothing I can't live without, but it's a cool tool for teaching and type debugging.

Research fractional integer tests

https://mumuki.io/central/exercises/4259-programacion-funcional-practica-valores-y-funciones-esnumeropositivo

3.4 and -8.7 tests are failing, the first test is being run on both cases.

Type validation should be consistent in editor and console

Currently the editor is deferring type errors, while console not. This behaviour should be consistent

some functions wont show properly on the console

Right now, when we write for example length in the console, it gives the following output:

<interactive>:2:1:
No instance for (Foldable t0) arising from a use of ‘it’
The type variable ‘t0’ is ambiguous
Note: there are several potential instances:
instance Foldable (Either a) -- Defined in ‘Data.Foldable’
instance Foldable Data.Proxy.Proxy -- Defined in ‘Data.Foldable’
instance GHC.Arr.Ix i => Foldable (GHC.Arr.Array i)
-- Defined in ‘Data.Foldable’
...plus three others
In the first argument of ‘print’, namely ‘it’
In a stmt of an interactive GHCi command: print it

instead of the desired <function>

this does not happen for every function.

Problem with Expectation Has Anonymous Variable

Ejercicio: Pattern Matching con Tuplas - Lección 7

Solución:
poderSoldado (_, str, dex) = str * dex

Estado: passed_with_warnings

Objetivos que no se cumplieron:
Expectation Has Anonymous Variable

See http://algo2-undav.mumuki.io/guides/pdep-utn/mumuki-guia-funcional-funciones-partidas-pattern-matching-tuplas

Parece ser que la expectation del _ no estaría funcionando

putting function signature after definition may cause exercise to fail

take for example: https://mumuki.io/exercises/1684-programacion-funcional-practica-listas-promedio

Submission

largo = fromIntegral.length
largo:: (Foldable t, Num a) => t x -> a

promedio numeros = (sum numeros) / (largo numeros)
promedio:: Foldable t => t Int -> Int

will fail with a Could not deduce (Fractional Int) compiler error.

If, however, the type signature for largo is put before its definition, it passes just fine.

Tested this behaviour on GHC 8.0.2 with GHCi and a file with the previous content and this did not happen.

We're importing unwanted functions

Take https://mumuki.io/exercises/4258-programacion-funcional-practica-valores-y-funciones-comienzacona

A student submitted the following solution:

comienzaConA auja = head (auja) == 'a'
comienzaConA bote = head (bote) === 'a'

Said solution is not failing because a function === exists in the package Test.QuickCheck, which we are importing in the test hook.
This would also normally fail with a type error, because the return type of === and == do not coincide, but since we're deferring type errors and the second line is never evaluated given that the first pattern catches any value, an error never comes up.

We should probably change the imports in the test hook to import only the functions we actually need.

Also, this gave me an idea for a new smell... shouldn't we warn the student when they have unreachable code like in the given example? Thoughts @flbulgarelli ?

Add feedback feature

It should provide feedback for the following compilation problems:

• Type errors
• Application order: detect wrong expressions like 1 succ
• Using and and or instead of && and ||. Please notice that and and or are valid Prelude functions, but with different types.
• Using div in prefix form french quotes
• Using incorrect parenthesis like foo (2 3)

Adding a commented line makes orange exercises turn green

A couple of students showed be that when they kept as comment some previous version of some function in the editor, an exercise that is orange (warning) passes. For instance say that the following has a warning:

f = blabla

the following has not (passes):

f = blabla
-- bla

special characters misprinted in error messages