From: a7145@...
Date: 2014-01-17T01:19:44+00:00
Subject: [ruby-core:59816] [ruby-trunk - Feature #9423] Improve warning	semantics

Issue #9423 has been updated by Atlas Prime.


I realized if `-W0` is to remain the same meaning as it does now than one modification to the above idea is required: The warning levels must start with `1` instead of `0`. Zero would be equivalent to `nil`. So given that, and `example.rb` as:

    puts $WARN
    puts $VERBOSE

It would be:

    $ruby -W0 example.rb
    nil
    nil

    $ruby -W1 example.rb
    1
    false

    $ruby -W2 example.rb
    2
    true

    $ruby -W3 example.rb
    3
    true

    $ruby -w example.rb
    2
    true

Transitions would be (basically)

    # if no warnings
    if $VERBOSE.nil?      ->  if !$WARN

    # if medium warnings
    if $VERBOSE == false  ->  if $WARN

    # if strong warnings
    if $VERBOSE           ->  if $WARN && $WARN > 1

It would be nice if just `if $WARN > 1` would work for the last. But since $WARN can be `nil`, that's not possible. (Can `nil` be comparable to integers as if it were zero?) So while it would be nice for `$WARN == 0` to mean no warnings, instead of `nil`, it would mean that a simple `if $WARN` would not be possible --which I think is the preferable choice.



----------------------------------------
Feature #9423: Improve warning semantics
https://bugs.ruby-lang.org/issues/9423#change-44389

* Author: Atlas Prime
* Status: Feedback
* Priority: Normal
* Assignee: 
* Category: core
* Target version: current: 2.2.0
----------------------------------------
Two suggestions for future version of Ruby that wold make warning levels more intuitive easier to work with.

First, rename $VERBOSE to $WARN for these reasons:

* `ruby` flags that set $VERBOSE are `-w` and `-W` (warnings levels).
* $VERBOSE controls output produced by `warn` method.
* $VERBOSE and FileUtils:Verbose are unrelated.
* $WARN is shorter ;-)

Second, it is confusing that `nil` and `false` mean different levels. Instead of the current `nil` as level 0, `false` as level 1, and `true` as level 2, it would be nice if `nil` and `false` both mean "off", and then go from 0 on up to mean "on" of increasing degree. Just to clarify my meaning (not a use case example):

    # nil, false mean no warning
    if $WARN
      case $WARN
      when 0
        # lesser level of warning
      when 1
        # greater level of warning
      when 2
        # can go higher if needed for rare use case
      end
    end

These are incompatible changes, but can be phased-in with support both $WARN and $VERBOSE for intermediate period.




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