oop - Ruby - Setter methods for hash properties -

i've been tooling around ruby converting pen , paper rpg script.

right have character's stats kept in hash, able set via public method. got working with:

class character     attr_reader :str, :con, :dex, :wis, :int, :level, :mods, :stats     def initialize str, con, dex, wis, int, cha, level = 1         @stats = { :str => str, :con => con, :dex => dex, :wis => wis, :int => int, :cha => cha }         @mods = {}         @level = level          @stats.each_pair |key, value|             @mods[key] = ((value / 2 ) -5).floor         end     end      def []=(index, value)         @stats[index] = value     end end 

this allows me instantiate new character, update @stats running newchar.stats[:str] = 12

however, seem able modify @mods using method well, undesirable. newchar.mods[:str] = 15 alter @mods hash, understanding should not possible current setter method.

on separate note, iterator i'm using create @mods hash seems clunky haven't found better accomplish task.

you did not call []= method in example. done so:

newchar[:str] = 123 

instead of

newchar.stats[:str] = 123 

so call newchar.stats[:str] = 123 not need method definition. reason newchar.stats newchar.mods both return actual hash can altered.

one possible workaround freeze @mods variable can't altered more:

def initialize str, con, dex, wis, int, cha, level = 1     # omitted ...      @stats.each_pair |key, value|         @mods[key] = ((value / 2 ) -5).floor     end      @mods.freeze end 

this solution if never want able change @mods again. trying set value result in error:

newchar.mods[:con] = 123 # runtimeerror: can't modify frozen hash 

inside class, can, however, overwrite @mods entirely.

to summarize, full class be:

class character     attr_reader :str, :con, :dex, :wis, :int, :level, :mods, :stats     def initialize str, con, dex, wis, int, cha, level = 1         @stats = { :str => str, :con => con, :dex => dex, :wis => wis, :int => int, :cha => cha }         @mods = {}         @level = level          @stats.each_pair |key, value|             @mods[key] = ((value / 2 ) -5).floor         end          @mods.freeze     end end