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hedyorg / hedy

Hedy is a gradual programming language to teach children programming. Gradual languages use different language levels, where each level adds new concepts and syntactic complexity. At the end of the Hedy level sequence, kids master a subset of syntactically valid Python.
https://www.hedy.org
European Union Public License 1.2
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Suppress or translate 'bad input' #186

Closed Felienne closed 3 years ago

Felienne commented 3 years ago

f.e. this code at level4:

naam is ask hoe heet jij?
ifnaam is Hedy print 'leuk' else print 'minder leuk!'
Felienne commented 3 years ago

Placing some thought for myself about this issue for later reference:

The reason this happens that is Hedy sometimes produces invalid Python. When the invalid code is ran, Skult produces an error, of which we output just "bad input". Sadly the more detailed info (f.e. SyntaxError or RunTimeError) is not (easily) available.

Felienne commented 3 years ago

Here's a discussion for you @fpereiro to think about with me... The issue is that in Level 3 and up, we do not require '' around strings, but some kids use it (probably because they know it form other places/parents think it is needed or they generalize from print where it is needed.

What to do with this?? We can remove the ''?

image

Or escape so it ends up in the string?

image

What do you think? The final might make it more clear that they are not needed?

We can of course also catch and then give a warning (or error even, if we want?)

fpereiro commented 3 years ago

@Felienne interesting question!

I really like the second option, of consider quotes as non-special characters until they become part of the syntax. So, if you put quotes, we merely return them. It keeps things consistent: either the characters are non-special (non-syntactic) or they are. It also gives it an "arcade" feeling, of throwing something at Hedy and Hedy returning it back unchanged (unless the quote means something syntactically). And for those who know that quotes are used to, um, quote strings, it might surprise them too in a good way. If we can help along the realization that a character can stand for itself or as a syntactic entity, this would be amazing.

Implementation wise, it means we'd have to escape the quotes.

Do we require quotes at a certain level? (embarassing of me to ask at this stage!) If so, after that point, the quotes are mandatory and if you want to print quotes, you'll actually have to escape them!

Felienne commented 3 years ago

I really like the second option, of consider quotes as non-special characters until they become part of the syntax. So, if you put quotes, we merely return them. It keeps things consistent: either the characters are non-special (non-syntactic) or they are. It also gives it an "arcade" feeling, of throwing something at Hedy and Hedy returning it back unchanged (unless the quote means something syntactically).

Yeah that was the same reasoning I though when I build that option! Let's go for it then.

And for those who know that quotes are used to, um, quote strings, it might surprise them too in a good way. If we can help along the realization that a character can stand for itself or as a syntactic entity, this would be amazing.

Yeah I was hoping that could happen sometimes too, let's see!

Implementation wise, it means we'd have to escape the quotes.

Yeah that's not hard, in fact I already build it, the images above were actual runs not photoshopped.

Do we require quotes at a certain level? (embarassing of me to ask at this stage!) If so, after that point, the quotes are mandatory and if you want to print quotes, you'll actually have to escape them!

They are mandatory from Level 3, but I am not sure if we want to teach quotes and also escaping at the same time! I could be a separate level... But that's for another day.

fpereiro commented 3 years ago

Hi @Felienne ! Agreed on all points. And escaping definitely should be done later. I like the idea of putting a cliffhanger there for kids that want to figure out how to print quotes when quotes become syntactic. It seems like that could be a level of its own, and quite later too.

Good to know there's no photoshop involved... I wonder what would take more effort, if photoshop or directly changing the grammar!

Felienne commented 3 years ago

This change had already been merged into master (not sure when, oops) so this can be closed for now, although there might be other cases of bad input when invalid Python is generated.