What is the best way to handle common term which contains special chars, like C#, C++ - elasticsearch

Question

I have some documents contains c# or c++ in title which use standard analyzer.
When I query c# on title field, I got all c# and C++ documents, and c++ documents even have higher score than c# document. That makes sense, since both '#' and '++' are removed from token by standard analyzer.
What is the best way to handle this kind special terms? In my case specifically, I want c# documents got higher score than c++ documents when searching for "C#".

Answer 1

Here is approach you can use:
Introduce copy-field where you will have values with special characters. For that you'll need:
Introduce custom analyzer (whitespace tokenizer is important here - it will preserve your special characters):
PUT my_index
{
"settings":{
"analysis":{
"analyzer":{
"my_analyzer":{
"type":"custom",
"tokenizer":"whitespace",
"filter":[
"lowercase"
]
}
}
}
}
}
Create copy-field (_wcc suffix will stand for 'with special characters'):
PUT my_index
{
"mappings": {
"my_type": {
"properties": {
"prog_lang": {
"type": "text",
"copy_to": "prog_lang_wcc",
"analyzer": "standard"
},
"prog_lang_wcc": {
"type": "text",
"analyzer": "my_analyzer"
}
}
}
}
}
When issuing query itself you will combine query with boost against prog_lang_wcc field like this (it could be either multi-match or pure boolean + boost):
GET /_search
{
"query": {
"multi_match" : {
"query" : "c#",
"type": "match_phrase",
"fields" : [ "prog_lang_wcc^3", "prog_lang" ]
}
}
}