Different syntax about jstar HOT 6 CLOSED

Honestly, I've been thinking about making the then and do keywords optional for a while.
Let me explain better; since the language already uses newlines as statement ending characters, we can do something like this:

if cond
    ...
end

in this instance the parser would see this:

TOK(if) TOK(cond) TOK('\n') <-- This will take the place of 'then' while parsing
    ...
TOK(end)

And use the '\n' in place of then for the start of the block.
Same goes for while/ for and the do keyword.

Now, this solution would work well, but I still want to mantain support for the old syntax, both for backwards-compatibility and because it permits writing one-line statements:

if cond then print('true!') end

Without then the parser would have no idea when to stop parsing the condition and start the block.
Unfortunately this means that the old keywords would still be reserved.

As for the end keyword, well, this is unfortunately necessary.
The only way to get rid of it would be to use braces (which I don't want to do at this stage of the language), or by using indentation-style blocks like in python, which would add other classes of problems in the language at large.

Having said that, if you're intrested in this change i would gladly implement it.
I still need to figure a few things like how to restructure the CLI to permit multi-line input without relying on the then or do keyword to signal the start of a block, but aside from this should be pretty simple.

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I don't have much of a problem with the end keyword at all, I really like this solution

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I sort of implemented the change in the opt-keywords branch. You can take a look at the core.jsr file to see how the language looks without the then and do keyword.

Honestly, the change looked good on paper but without the keywords the code is a bit harder to read in my opinion, I'm not quite sure if I want to merge it into the main branch at this point. I need to think this through.

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I looked at it, It does seem hard to read. I also didn't think about how it made the language more dependent on white space. I think the way you made the language was better.

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I decided to take a look at how other languages handle the then and do keywords. As I was searching I stumbled upon Julia, that simply omits them and doesn't seem to rely on newlines to tell the start of a block. It made me realize that, since in J* we do not allow side-effect-free expressions to appear as statements, we don't need to check for newlines too! Code like this is actually possible:

if condition print("true!") end

As a bonus, omitting the keywords in this way, actually simplifies the implementation of the parser a fair bit!
Also, after some time getting used to the syntax I changed my opinion on it, and think this way the code is more pleasant to write and more approachable to newcomers.
So, in the end I completely stripped the keywords from the grammar, making it more simple and allowing the use of then and do as variable names.
You can check out the changes in version 1.7

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Implemented in f49d72c

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