Correctly folding ASCII characters in Elasticsearch - elasticsearch

Question

I'm looking into supporting folding of non standard ASCII characters like this guide suggests.
PUT /my_index
{
"settings": {
"analysis": {
"analyzer": {
"folding": {
"tokenizer": "standard",
"filter": [ "lowercase", "asciifolding" ]
}
}
}
}
}
Strangely enough, I'm not able to replicate the sample in the first snippet of code.
When I execute
GET /my_index/_analyze?analyzer=folding&text=My œsophagus caused a débâcle
the following tokens are returned:
sophagus, caused, a, d, b, cle
What I want to achieve is:
Variations of the spelling of words like "école" (e.g. ecole, ècole) should be treated as the same word.
Right now, if I execute
GET /my_index/_analyze?analyzer=folding&text=école ecole
I get the tokens cole, ecole
These are the settings I currently use for the text analysis of the documents
"analysis": {
"filter": {
"french_stop": {
"type": "stop",
"stopwords": "_french_"
},
"french_elision": {
"type": "elision",
"articles": [
"l",
"m",
"t",
"qu",
"n",
"s",
"j",
"d",
"c",
"jusqu",
"quoiqu",
"lorsqu",
"puisqu"
]
},
"french_stemmer": {
"type": "stemmer",
"language": "light_french"
}
},
"analyzer": {
"index_French": {
"filter": [
"french_elision",
"lowercase",
"french_stop",
"french_stemmer"
],
"char_filter": [
"html_strip"
],
"type": "custom",
"tokenizer": "standard"
},
"sort_analyzer": {
"type": "custom",
"filter": [
"lowercase"
],
"tokenizer": "keyword"
}
}
}
My idea was to change the filters of the index_French analyzer so that the list is the following:
"filter": ["french_elision","lowercase","asciifolding","french_stop","french_stemmer"]
Thanks for your help.

Answer 1

In Sense you need to call the _analyze endpoint like this and it will work:
POST /foldings/_analyze
{
"text": "My œsophagus caused a débâcle",
"analyzer": "folding"
}
You'll get
{
"tokens": [
{
"token": "my",
"start_offset": 0,
"end_offset": 2,
"type": "<ALPHANUM>",
"position": 0
},
{
"token": "oesophagus",
"start_offset": 3,
"end_offset": 12,
"type": "<ALPHANUM>",
"position": 1
},
{
"token": "caused",
"start_offset": 13,
"end_offset": 19,
"type": "<ALPHANUM>",
"position": 2
},
{
"token": "a",
"start_offset": 20,
"end_offset": 21,
"type": "<ALPHANUM>",
"position": 3
},
{
"token": "debacle",
"start_offset": 22,
"end_offset": 29,
"type": "<ALPHANUM>",
"position": 4
}
]
}