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Class: RuboCop::Cop::Style::ExponentialNotation

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/exponential_notation.rb

Overview

Enforces consistency when using exponential notation for numbers in the code (eg 1.2e4). Different styles are supported:

  • scientific which enforces a mantissa between 1 (inclusive) and 10 (exclusive).

  • engineering which enforces the exponent to be a multiple of 3 and the mantissa to be between 0.1 (inclusive) and 10 (exclusive).

  • integral which enforces the mantissa to always be a whole number without trailing zeroes.

Examples:

EnforcedStyle: scientific (default)

# Enforces a mantissa between 1 (inclusive) and 10 (exclusive).

# bad
10e6
0.3e4
11.7e5
3.14e0

# good
1e7
3e3
1.17e6
3.14

EnforcedStyle: engineering

# Enforces using multiple of 3 exponents,
# mantissa should be between 0.1 (inclusive) and 1000 (exclusive)

# bad
3.2e7
0.1e5
12e5
1232e6

# good
32e6
10e3
1.2e6
1.232e9

EnforcedStyle: integral

# Enforces the mantissa to have no decimal part and no
# trailing zeroes.

# bad
3.2e7
0.1e5
120e4

# good
32e6
1e4
12e5

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

SYMBOL_TO_STRING_CACHE

Class Attribute Summary

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

.builtin?

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Cops (other than builtin) are encouraged to implement this.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect,
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range, #reset_investigation, #use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#engineering?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/exponential_notation.rb', line 79

def engineering?(node)
  mantissa, exponent = node.source.split('e')
  return false unless /^-?\d+$/.match?(exponent)
  return false unless (exponent.to_i % 3).zero?
  return false if /^-?\d{4}/.match?(mantissa)
  return false if /^-?0\d/.match?(mantissa)
  return false if /^-?0.0/.match?(mantissa)

  true
end

#integral(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/exponential_notation.rb', line 90

def integral(node)
  mantissa, = node.source.split('e')
  /^-?[1-9](\d*[1-9])?$/.match?(mantissa)
end

#message(_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/exponential_notation.rb', line 110

def message(_node)
  MESSAGES[style]
end

#offense?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/exponential_notation.rb', line 95

def offense?(node)
  return false unless node.source['e']

  case style
  when :scientific
    !scientific?(node)
  when :engineering
    !engineering?(node)
  when :integral
    !integral(node)
  else
    false
  end
end

#on_float(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/exponential_notation.rb', line 68

def on_float(node)
  add_offense(node) if offense?(node)
end

#scientific?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/exponential_notation.rb', line 74

def scientific?(node)
  mantissa, = node.source.split('e')
  /^-?[1-9](\.\d*[0-9])?$/.match?(mantissa)
end