OSM "level" translation in fluent

playground.ftl

### input data: ground floor = level 0
### for OSM "level" tag, see https://wiki.openstreetmap.org/wiki/Key:level

### KNOWN BUGS:
### 1. I cannot remove the minus (-) sign from negative levels. See https://github.com/projectfluent/fluent/issues/228
### 2. I cannot properly calculate +1 for the US style. See https://github.com/projectfluent/fluent/issues/227

## Style, where floor = level 0 = input data

# German/European style in German
# Note: this should sound "FAMILAR" to speakers of German
floor_EUROP_in_DE =
    { $level ->
        [-2] im { $level }. Untergeschoss
        [-1] im 1. Untergeschoss
        [0] im Erdgeschoss
        [one] im 1. Obergeschoss
       *[other] im { $level }. Obergeschoss
    }

# German/European style but translated in English
# Note: this should sound "WRONG" to speakers of US-English, but familar to speakers in GB-English.
floor_EUROP_in_EN =
    { $level ->
        [-2] on basement floor { $level }
        [-1] basement floor 1
        [0] on ground floor
        [one] on floor one
       *[other] on floor { $level }
    }


## Style, where ground floor = level 1

# US style in English
# Note: this should sound "FAMILIAR" to speakers of English
floor_ENGLI_in_EN =
    { $level ->
        [-2] on basement floor B{ $level }
        [-1] on basement floor B
        [0] on ground floor
        [one] on floor 2
       *[other] on floor { $level }+1
    }

# US style in German
# Note: this should sound "WRONG" to speakers of German.
floor_ENGLI_in_DE =
    { $level ->
        [-2] im Untergeschoss B{ $level }
        [-1] Im Untergeschoss B
        [0] im Erdgeschoss
        [one] im 2. Obergeschoss
       *[other] im { $level }+1. Geschoss
    }

playground.json

{
    "level": 1
}

setup.json

{
    "locale": "en-US",
    "dir": "ltr"
}