K +/!100
Python sum(range(100))
Haskell sum [0..99]
Rust (0..100).sum()
Ruby (0..99).sum
There are plenty of ultra-concise languages for toy problems like these; they are called ‘golfing languages’. Ultimately it's a bit pointless since most of the time people aren't playing code golf.
(The issue with setting everything to obscure ultra-compressed keywords isn't that it's not possible to learn those keywords, but that most of the time programming is done over specific and customized domains with larger and problem-specific vocabularies.)
Except in K all the idioms are laid flat. As pointed out in the article, the K code is the equivalent of range(100).reduce(operator.add), it encapsulates the entire meaning, there is no need for an intermediate function definition because that would be longer than the code itself.
(The issue with setting everything to obscure ultra-compressed keywords isn't that it's not possible to learn those keywords, but that most of the time programming is done over specific and customized domains with larger and problem-specific vocabularies.)