[Haskell-cafe] Chaining a map over lists with lenses

[Michal Antkiewicz]

The & is the same as $ with arguments inverted. So instead of

t & myField . traversed . otherField %~ (++ "X")

you could write

myField . traversed . otherField %~ (++ "X") $ t

(if I recall correctly...)
Michal

On Fri, Oct 10, 2014 at 11:03 AM, Nicola Gigante <nicola.gigante at gmail.com>
wrote:

>
> Il giorno 10/ott/2014, alle ore 16:36, Daniel Trstenjak <
> daniel.trstenjak at gmail.com> ha scritto:
>
> >
> > Hi Nicola,
> >
> > there's 'traversed' to access every entry of a traversable structure,
> > e.g. appending a "X" at the end of each 'otherField':
> >
> >   t & myField . traversed . otherField %~ (++ "X")
> >
> >
> > And there's '^..' to return a list of each entry of a traversable
> structure:
> >
> >   t ^.. myField . traversed . otherField
> >
>
> Thank you for both the answers!
>
> So my error was to presume that everything can be
> done with (^.) (which is view, if I’m correct).
>
> So I have to understand now, what is the & operator?
>
> >
> > Greetings,
> > Daniel
>
> Thank you,
> Nicola
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