class Ameba::Rule::Style::RedundantNext

• Ameba::Rule::Style::RedundantNext
• Ameba::Rule::Base
• Reference
• Object

Overview

A rule that disallows redundant next expressions. A next keyword allows a block to skip to the next iteration early, however, it is considered redundant in cases where it is the last expression in a block or combines into the node which is the last in a block.

For example, this is considered invalid:

block do |v|
  next v + 1
end

block do |v|
  case v
  when .nil?
    next "nil"
  when .blank?
    next "blank"
  else
    next "empty"
  end
end

And has to be written as the following:

block do |v|
  v + 1
end

block do |v|
  case arg
  when .nil?
    "nil"
  when .blank?
    "blank"
  else
    "empty"
  end
end

Configuration params

1. allow_multi_next, default: true

Allows end-user to configure whether to report or not the next statements which yield tuple literals i.e.

block do
  next a, b
end

If this param equals to false, the block above will be forced to be written as:

block do
  {a, b}
end

2. allow_empty_next, default: true

Allows end-user to configure whether to report or not the next statements without arguments. Sometimes such statements are used to yield the nil value explicitly.

block do
  @foo = :empty
  next
end

If this param equals to false, the block above will be forced to be written as:

block do
  @foo = :empty
  nil
end

YAML config example

Style/RedundantNext:
  Enabled: true
  AllowMultiNext: true
  AllowEmptyNext: true

Included Modules

• Ameba::AST::Util
• YAML::Serializable

Defined in:

Constant Summary

MSG = "Redundant `next` detected"

Constructors

• .new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)
• .new(config = nil)

  A rule that disallows redundant next expressions.

• .new(*, __context_for_yaml_serializable ctx : YAML::ParseContext, __node_for_yaml_serializable node : YAML::Nodes::Node)

Class Method Summary

• .deprecated?

  Returns true if this rule is deprecated, false otherwise.

• .deprecation_reason : String | Nil

  Returns the deprecation reason for this rule, if there is any.

• .documentation_url : String

  Returns the documentation URL for this rule.

• .parsed_doc : String | Nil

  Returns the documentation for this rule, if there is any.

• .to_json_schema(builder : JSON::Builder) : Nil

Instance Method Summary

• #allow_empty_next=(allow_empty_next : Bool)
• #allow_empty_next? : Bool
• #allow_multi_next=(allow_multi_next : Bool)
• #allow_multi_next? : Bool
• #description : String
• #description=(description : String)
• #enabled=(enabled : Bool)
• #enabled? : Bool
• #excluded : Set(String) | Nil
• #excluded=(excluded : Set(String) | Nil)
• #severity : Ameba::Severity
• #severity=(severity : Ameba::Severity)
• #since_version : SemanticVersion | Nil
• #since_version=(since_version : String)
• #test(source, node : Crystal::Next, visitor : AST::RedundantControlExpressionVisitor)
• #test(source, node : Crystal::Block)

Constructor Detail

block do |v|
  next v + 1
end

block do |v|
  case v
  when .nil?
    next "nil"
  when .blank?
    next "blank"
  else
    next "empty"
  end
end

block do |v|
  v + 1
end

block do |v|
  case arg
  when .nil?
    "nil"
  when .blank?
    "blank"
  else
    "empty"
  end
end

block do
  next a, b
end

block do
  {a, b}
end

block do
  @foo = :empty
  next
end

block do
  @foo = :empty
  nil
end

Style/RedundantNext:
  Enabled: true
  AllowMultiNext: true
  AllowEmptyNext: true

Class Method Detail

Ameba::Rule::Lint::Syntax.documentation_url
# => "https://crystal-ameba.org/api/master/Ameba/Rule/Lint/Syntax.html"

module Ameba
  # This is a test rule.
  # Does nothing.
  class Rule::MyRule < Rule::Base
    def test(source)
    end
  end
end

Ameba::Rule::MyRule.parsed_doc # => "This is a test rule.\nDoes nothing."

Instance Method Detail