"no variable or argument declarations are necessary."

[Duncan Booth]

Antoon Pardon wrote:

> A language where variable have to be declared before use, would allow
> to give all misspelled (undeclared) variables in on go, instead of
> just crashing each time one is encounterd.

Wrong. It would catch at compile-time those misspellings which do not 
happen to coincide with another declared variable. It would give the 
programmer a false sense of security since they 'know' all their 
misspellings are caught by the compiler. It would not be a substitute for 
run-time testing.

Moreover, it adds a burden on the programmer who has to write all those 
declarations, and worse it adds a burden on everyone reading the code who 
has more lines to read before understanding the code. Also there is 
increased overhead when maintaining the code as all those declarations have 
to be kept in line as the code changes over time.

It's a trade-off: there is a potential advantage, but lots of 
disadvantages. I believe that the disadvantages outweight the possible 
benefit. Fortunately there are plenty of languages to choose from out 
there, so those who disagree with me are free to use a language which does 
insist on declarations.