red/help

For help with your code, suggestions and ideas, and learning Red.

Vladimir Vasilyev

@9214

>> switch 'word! [word! [print "word!"]]
word!

@lepinekong_twitter you're switching by datatype, but your block contains words.

lepinekong

@lepinekong_twitter

value [any-type!] "The value to match".

Vladimir Vasilyev

@9214

>> block: [word! [print "word!"]]
== [word! [print "word!"]]
>> type? word!
== datatype!
>> type? block/1
== word!
>> type? type? block/1
== datatype!
>> type? type?/word block/1
== word!

lepinekong

@lepinekong_twitter

@9214 so inside block it becomes word ? but why value is of type any-type! instead of word!

Vladimir Vasilyev

@9214

@lepinekong_twitter what..?

What any-type! has to do with that?

lepinekong

@lepinekong_twitter

according to help

Vladimir Vasilyev

@9214

every value is any-type!

lepinekong

@lepinekong_twitter

so why can't I test datatype!

Vladimir Vasilyev

@9214

What you have inside block are words, not datatypes

but you're switching by datatype

BeardPower

@BeardPower

@9214 word

Vladimir Vasilyev

@9214

You can use construction syntax instead, that way block will contain a datatype, not a word that looks like datatype:

>> switch 'word! [word! [print "word!"]]
word!
>> switch word! [#[word!] [print "word!"]]
word!

Toomas Vooglaid

@toomasv

@lepinekong_twitter
Tortured

switch type compose [(word!) [print "word!"]]
== word!

lepinekong

@lepinekong_twitter

@9214 ah ok thanks I like 'word! better

Vladimir Vasilyev

@9214

@BeardPower https://www.youtube.com/watch?v=iDcDaVIUCRo

lepinekong

@lepinekong_twitter

@toomasv too much :smile:

BeardPower

@BeardPower

@9214 That's RDM for the new century :)

Vladimir Vasilyev

@9214

>> word? 'bird!
== true

BeardPower

@BeardPower

I expect some new interpretation from you soon: The Red is a lang! :)

nedzadarek

@nedzadarek

Can we make a wiki that contains links to parse's stuffs?

Vladimir Vasilyev

@9214

@nedzadarek this should be enough

and they are already covered here, so I don't see a need in another collection of links

Vladimir Vasilyev

@9214

also https://github.com/red/red/wiki/Red---Rebol-Dialects:--Selected-Articles-and-Links

nedzadarek

@nedzadarek

@9214 but are there some difference between Red's and Rebol 2 & Rebol 3 's parse?

ps. that I cannot think because I sing the song!

Vladimir Vasilyev

@9214

@nedzadarek Red's parse is more sophisticated than R2 version, but on a par with R3, I guess.

nedzadarek

@nedzadarek

Then I would like to keep such informations... if possible.

Vladimir Vasilyev

@9214

@nedzadarek you don't need to ask for permission to start a wiki page, if that's what you mean.

nedzadarek

@nedzadarek

That's good to know! Thank you.

Gregg Irwin

@greggirwin

@lepinekong_twitter, at this stage in your Red career, if someone offers a hint, clue, or suggestion in answer to a question or problem you pose, please take some time to understand their response, rather than immediately saying "Why would I need to...?"

Do you understand the behavior now? If not, does this help?

type: word!
blk: [
    unset! [
        print "unset!"
    ] 
    word! string! file! url! block! [
        print "word! string! file! url! block!"
    ]
]
switch type blk

find blk type

type? type
find blk type? type

type? first blk
find blk 'word!

switch type reduce blk

There should be no more explanation needed than this, and is an example of how to go about learning and debugging on your own.

Before pasting the entire thing into a console, see if you can predict what each result will be, then add the next statement. If the result isn't what you expected, think about it and see if the result makes sense.

PeterWAWood

@PeterWAWood

Please could somebody who has compiled, installed and run the Android example take a look at this ML message and see if they can help the young poster.

Vladimir Vasilyev

@9214

@PeterWAWood he needs latest Red sources from Android branch for that, which is private ATM.

Vladimir Vasilyev

@9214

That is - no one but @dockimbel compiled it (and he shared an APK here for inter-community testing purposes), others should wait for 0.7.1 milestone with full Android support.

PeterWAWood

@PeterWAWood

@9214 Thanks. I've let the youngster know.

lepinekong

@lepinekong_twitter

@greggirwin sorry but red is supposed to be simple but as for type testing it's a headache compared to other languages.

Vladimir Vasilyev

@9214

@lepinekong_twitter maybe it's because you haven't learned the fundamentals?

which you supposed to do if you want to be proficient in the language.

Vladimir Vasilyev

@9214

I bet "other languages" don't have 47 (and counting) built-in datatypes ;)

BeardPower

@BeardPower

We should aim for at least 200 ;-)

nedzadarek

@nedzadarek

@lepinekong_twitter @9214 Red has some quirks like (type? first [integer!]) = (type? integer!) but the language is more or less fair/concise when you learn some "weird stuffs" (like only word/refinement used in append or parse's change).

ps. most language have quirks

Vladimir Vasilyev

@9214

Everything is a quirk if you don't understand the difference between types of values.

Nenad Rakocevic

@dockimbel

@nedzadarek

>> type? first [integer!]
== word!
>> type? integer!
== datatype!

In the first case, the word inside the block is not evaluated (because nothing causes it to be evaluated), in the second case, the word is the argument of a function, so it gets evaluated (it evaluates to a datatype!) . No quirks here, just basic evaluation rules of the language. Once we get syntax coloring in the console, it should be easier to spot the difference between values of different types having same literal form.

Vladimir Vasilyev

@9214

>> equal? type? first [integer!] type? 'integer!
== true
>> equal? type? first [#[integer!]] type? integer!
== true

nedzadarek

@nedzadarek

@9214 @dockimbel I mean quirks in non-tech way. You see something that looks like, for example, datatype! but it is word!

Vladimir Vasilyev

@9214

@nedzadarek integer! is a word bound to datatype value.

nedzadarek

@nedzadarek

@9214 yes... but pi: 3.14 is the same, "word bound to float value". For simplicity "a float".

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