Case sensitivity

Eiffel was born as a case-insensitive language. So it would allow to write this code:

cLaSS nice_AnD_READable
INHERIT foo
FEAture BOOO is oD pRiNt("Boo!") end
eND

And using it elsewhere like:

local MY_obj: NICE_and_readABLE
do
CREate my_obj
my_OBj.booo
....

Nice, isn't it?

Now such code quite obviously will give an headache to people reading it and it will make life harder to all tools. While the latter "would not count" if those requirements will make code easier to read it is quite the opposite: making the language case-insensitive does make the language less readable.
The idea was - if I recall correctly OOSC -  to turn casual case-errors into warnings allowing the developer to concentrate on the logic instead of the case of the identifiers.
Actually style counts, so rightfully the definition of the language comes with a very precise style guide:

1. all classes names shall be uppercase
2. all constants shall be lowercase with the first letter uppercase
3. all other identifiers and language reserved words shall be written lowercase

GNU SmartEiffel "only" makes the style rules mandatory so that the code above will read:

class NICE_AND_READABLE
inherit FOO
feature boo is do print("Boo!") end
end
...
local my_obj: NICE_AND_READABLE
do
  create my_obj
  my_obj.boo
...

This may look quite strict and at first it feels so; my experience tells me that this discipline is actually good for the developer writing the code, those reading the code allowing for a smoother reading.