Classic mistakes in language design that have to be fixed later.
- "We don't need any attributes", like "const" or "mut". This eventually gets retrofitted, as it was to C, but by then there is too much code without attributes in use. Defaulting to the less restrictive option gives trouble for decades.
- "We don't need a Boolean type". Just use integers. This tends to give trouble if the language has either implicit conversion or type inference. Also, people write "|" instead of "||", and it almost works. C and Python both retrofitted "bool". When the retrofit comes, you find that programs have "True", "true", and "TRUE", all user-defined.
Then there's the whole area around Null, Nil, nil, and Option. Does NULL == NULL? It doesn't in SQL.
- "We don't need any attributes", like "const" or "mut". This eventually gets retrofitted, as it was to C, but by then there is too much code without attributes in use. Defaulting to the less restrictive option gives trouble for decades.
- "We don't need a Boolean type". Just use integers. This tends to give trouble if the language has either implicit conversion or type inference. Also, people write "|" instead of "||", and it almost works. C and Python both retrofitted "bool". When the retrofit comes, you find that programs have "True", "true", and "TRUE", all user-defined.
Then there's the whole area around Null, Nil, nil, and Option. Does NULL == NULL? It doesn't in SQL.