On Friday, March 5, 2004, 3:04:29 PM, Yukihiro wrote:

> | I.e., what about changing Proc to Block?
> | Then, we can have 'proc' and its alias 'lambda'.

> Maybe.  But we need to think about compatibility.

I wouldn't worry about 1.8 -> 2.0 compatibility.  1.8 is good enough
to be a "finished product" (with continued bug fixes etc).  No-one
should need to upgrade their programs to 2.0.

If people see a benefit in upgrading (speed, for instance), then they
must expect some costs (time to port from Ruby1.8 to Ruby2.0).

Some simple incompatibilities could be flagged by the interpreter.
For example:

  ruby2 -e --compatibility-diagnostics 'x = proc { 5 }'
  -e:1: Ruby 1.8 'proc' no longer used; try 'lambda'

My 2c,
Gavin