FTL generation

[RedMser]

Could take the PotGenerator class, create an abstract base class / plugin registration system, then allow generating FTL files the same way. Obviously needs larger upstream changes.

While POT uses English messages as translation keys, FTL has separate keys. So unlike POT, you'll want to enter translation keys into your UI, and have those get extracted like key = UNTRANSLATED. Not sure how this works with ETR/ETRN translations though (I don't think FTL supports spaces in translation keys, so those might need to be converted to a "compatible" format)...

Alternative approach would be a custom EditorPlugin that adds some kind of UI. This provides more flexibility:

• It could be interesting to allow multiple FTL files split up in some way, e.g. by folder or by file.
• Existing files can be merged so that existing changes don't get lost - new keys are appended.
• Similar "translation extraction plugin" class that the user can write to decide how certain files should fill a FTL:
  • Would also support extracting attributes and terms.
  • Could let the user choose whether they want the messages themselves to be translation keys (with some "convert illegal characters to underscores/dashes" logic), or define custom translation keys.
  • Could generate boilerplate for plural selectors?

---

First draft for how to configure this (no UI, just plaintext multiline):

locales = ["en", "de", ...]

[source files regex]
[generated ftl files]
...

• Each file in the project is iterated and matched against the specified source regex.
  • Capture groups can be re-used later.
• If a file matches, loop over all configured locales.
  • For each locale, fill out the ftl file string's placeholders:
  • {$locale} is replaced with the current locale
  • {$n} is replaced with the n-th matched capture group
  • If the ftl file does not exist, create it.
  • If the ftl file already exists, merge it with the existing contents.
  • Create new messages.
  • Leave existing messages untouched.
  • Mark no longer existing messages with a comment for inspection.
• Repeat this process for all source > ftl lines.

Example syntax:

ui/(.+)\.tscn
i18n/{$1}.{$locale}.ftl

[RedMser]

Readme has been updated with up-to-date infos on how to use the feature