> I would love to see a language try to implement a rule where only an indented line is considered part of the previous expression.

After python, it seems like every language decided that making parsing depend on indents was a bad idea. A shame, because humans pretty much only go by indents. An example I've frequently run into is where I forget a closing curly brace. The error is reported at the end of the file, and gives me no advice on where to go looking for the typo. The location should be obvious, as it's at exactly the point where the indentation stops matching the braces. But the parser doesn't look at indents at all, so it can't tell me that.

I was much more opposed to this early on than I am now. With modern IDEs and extensions handling tabs vs spaces, tab width, and formatting, python ends up being very easy to read and write. I use it daily, and while I hate it for other reasons, I can't remember the last time I had any issues with indentation.

we don't even use indents that way in natural language. We use things like bullet points, we need specific markers.

space is for spacing, tabs are for tabulation, they are not in any human language I know of used as terminators of statements. You know what is the equivalent of an indent or a semicolon in english? a period. <-

We have paragraph breaks just like this to delimit blocks of english statements.

A semi-colon is used to indicate part of a sentence is done, yet there is still related continuation of the statement that is yet to be finished. Periods are confusing because they're used in decimal points and other language syntax, so a semi-colon seems like a good fit.

If I had my pick, I would use a colon to indicate the end of a statement, and a double colon '::' to indicate the end of a block.

func main(): int i - 0: do: i=i+1: print(i): while(i<10):: ::

another downside of indentation is it's award to do one-liners with such languages, as with python.

There is a lot of subjectivity with syntax, but python code for example with indents is not easy for humans to read, or for syntax validators to validate. it is very easy for example to intend a statement inside a for loop or an if/else block in python (nor not-intend it), and when pasting around code you accidentally indent one level off without meaning to. if you know to look for it, you'll catch it, but it's very easy to miss, since the mis-indented statement is valid and sensible on its own, nothing will flag it as unusual.

In my opinion, while the spirit behind indentation is excellent, the right execution is in the style of 'go fmt' with Go, where indenting your code for you after it has been properly parsed by the compiler/interpreter is the norm.

I would even say the first thing a compiler as well as interpreter do should be to auto-indent, and line-wrap your code. that should be part of the language standard. If the compiler can't indent your code without messing up logic or without making it unreadable, then either your code or the language design has flaw.

What language is this? In C I get the correct position of the error because GCC also monitors the indentation as it parses.

A linter can point out errors based on indentation, and they frequently do. There's no need for the language to do it and then band-aid additional fixes for problems caused by significant white space.

rustc does exactly that keeping the indent level of every unbalanced curly brace. It works OK, but it isn't perfect by any stretch. More heuristics are needed.

> An example I've frequently run into is where I forget a closing curly brace. The error is reported at the end of the file, and gives me no advice on where to go looking for the typo. The location should be obvious, as it's at exactly the point where the indentation stops matching the braces. But the parser doesn't look at indents at all, so it can't tell me that.

That's somewhat a quality of service issue though. Compilers should look at where the braces go out of kilter vs indentation and suggest the possible unmatched opening brace.

Scala 3 decided to go with indents.

The issue is that you find you very often want to break those roles. Python basically has `elif` because `else if` would make each branch nest one level deeper which isn't what one wants, except Python uses exceptions for flow control so you find yourself having to use `except ... try` as an analogue to `else if` but not `excetry` exists to do the same and stop the indentation.

There are many other examples. It exists to give people freedom. Also, while humans only go by intendation it's very hand for text editing and manipulation without requiring special per-language support to move the cursor say to the nearest closing brace and so forth.