cldr-plurals
Tokenizes and parses CLDR plural rules and provides a mechanism for emitting them as source code.
Installation
gem install cldr-plurals
Usage
require 'cldr-plurals'
Rules
The CLDR data set contains plural information for numerous languages in an expression-based format defined by Unicode's TR35. This gem can tokenize, parse, and emit these rules as source code. Currently Ruby and Javascript are supported.
Tokenizing
Generate a list of tokens using the Tokenizer
class:
tokens = CldrPlurals::Compiler::Tokenizer.tokenize(
'v = 0 and i % 10 = 1 and i % 100 != 11'
)
Parsing
Once you have a token list, the Parser
class can turn them into an abstract syntax tree, (i.e a CldrPlurals::Compiler::Rule
) for you:
rule = CldrPlurals::Compiler::Parser.new(tokens).parse
Emitting
Rules can be emitted as either Ruby or Javascript source code via the appropriate Emitter
class:
ruby_code = CldrPlurals::RubyEmitter.emit_rule_standalone(rule)
For our example above, the emitted standalone ruby code looks like this:
lambda { |n, i, f, t, v, w| ((v == 0 && i % 10 == 1) && i % 100 != 11) }
Rule Lists
The CLDR data set defines groups of rules that together determine the plural form for a given number. Create a RuleList
object to group rules together. RuleList
s take care of the tokenizing and parsing steps for you:
rules = CldrPlurals::Compiler::RuleList.new(:ru).tap do |rule_list|
rule_list.add_rule(:one, 'v = 0 and i % 10 = 1 and i % 100 != 11')
rule_list.add_rule(:few, 'v = 0 and i % 10 = 2..4 and i % 100 != 12..14')
rule_list.add_rule(:many, 'v = 0 and i % 10 = 0 or v = 0 and i % 10 = 5..9 or v = 0 and i % 100 = 11..14')
end
Note that there's no need to add an explicit rule for the other
plural form.
RuleList
s can be emitted in their entirety via the to_code
method, which accepts a target language as an argument:
rules.to_code(:ruby)
Which produces:
lambda { |num, runtime| n = runtime.n(num); i = runtime.i(num); v = runtime.v(num); w = runtime.w(num); f = runtime.f(num); t = runtime.t(num); (((v == 0 && i % 10 == 1) && i % 100 != 11) ? :one : (((v == 0 && (2..4).include?(i % 10)) && !(12..14).include?(i % 100)) ? :few : ((((v == 0 && i % 10 == 0) || (v == 0 && (5..9).include?(i % 10))) || (v == 0 && (11..14).include?(i % 100))) ? :many : :other))) }
OR
rules.to_code(:javascript)
Which produces:
(function(num, runtime) { var n = runtime.n(num); var i = runtime.i(num); var v = runtime.v(num); var w = runtime.w(num); var f = runtime.f(num); var t = runtime.t(num); return (((v == 0 && i % 10 == 1) && i % 100 != 11) ? 'one' : (((v == 0 && ((i % 10 >= 2) && (i % 10 <= 4))) && !((i % 100 >= 12) && (i % 100 <= 14))) ? 'few' : ((((v == 0 && i % 10 == 0) || (v == 0 && ((i % 10 >= 5) && (i % 10 <= 9)))) || (v == 0 && ((i % 100 >= 11) && (i % 100 <= 14)))) ? 'many' : 'other'))); })
Executing Targets
You may have noticed that emitted target source code requires a runtime (the second argument). Runtimes provide methods to determine the 'parts' of a number, like the decimal portion or the number of decimals without trailing zeroes. Runtimes for Ruby and Javascript exist as separate rubygems, so you'll need to include them in your project before being able to execute target code. Each runtime gem's README contains instructions on how to use it. Here are some quick examples:
Ruby:
# construct RuleList...
require 'cldr-plurals/ruby_runtime'
ruby_code = rules.to_code(:ruby)
plural_proc = eval(ruby_code)
plural_proc.call('3', CldrPlurals::RubyRuntime) # => :few
Javascript:
# construct RuleList...
require 'cldr-plurals/javascript_runtime'
plural_code = rules.to_code(:javascript)
File.open('./plurals-ru.js', 'w+') do |f|
f.write("
var runtime = #{CldrPlurals::JavascriptRuntime.source};
var rules = #{plural_code};
console.log(rules('3', runtime));
")
end
Then, running node ./plurals-ru.js
should print 'few'
.
Requirements
No external requirements.
Running Tests
bundle exec rake
should do the trick. Alternatively you can run bundle exec rspec
, which does the same thing.
Authors
- Cameron C. Dutro: http://github.com/camertron