I18n Interpolation

Suggestion

# I18n Interpolation plan

##  Introduction

### Inline pluralisation

These propositions different interpolations indicators are used. `%{}'` and `%<{}>` are 2 of them. In this discussion we should focus on the content of these tags. What type of indicators we would be using is more of a compatibility and/or performance question.

#### Value interpolations

When creating a translatable string, it can be a hastle to create multiple keys for each pluralisation within a sentence.

These interpolation syntaxes could be used for more than just pluralisation. Gender differentiation can also be acomplished with these notations.

##### Tr8n syntax

`"THere %{count|| is, are} %{count| ninja, ninjas} in this room %{current_user.gender| girly, boys, awesome} room" # => There are 5 ninjas in this room girly room  | There is 1 ninja in this room boys room`

* Compact notation
* Readable without prior knowledge
* Interpolation rules are "assumed" and not clear from the provided string

##### Twitter syntax

`"THere %<{ 'count': { 'one': 'is', 'other': 'are' } }> %{ 'count': { 'one': 'one ninja', 'other': '%{count} ninjas' } } in this room %<{ 'current_user.gender': { 'male': 'boys', 'female': 'girly', 'other': 'awesome' } }> room" # => There are 5 ninjas in this room girly room | There is one ninja in this room boys room`

* Verbose notation, clear what rules would be applied
* Less readable without prior knowledge
* Easily validatable translations

#### Decorator tokens

Today when we want to add markup to a translation, a string or html tags; we are forced to either put HTML in the string,

##### Tr8n syntax

`"You can [link: visit the site] or [strong: read this bold text]" # => You can <a href="/home">visit the site</a> or <strong>read this boldtext</a> `

##### Proposed I18n filters

See: https://github.com/svenfuchs/i18n/issues/148

There's also the Java's MessageFormat (JS port)