Nginx Lua regex match first word

I try to convert regex into Lua language, from

([a-zA-Z0-9._-/]+)

to

^%w+?([_-]%w+)

I want to make match first word with '-' and '_':

mar_paci (toto totot)
toi-re/3.9
pouri marc (sensor)
Phoenix; SAGEM

The result:

marc_paci
toi-re
pouri marc
Phoenix

The code used:

value = string.match(ngx.var.args, "^%w+?([_-]%w+)")

In the ^%w+?([_-]%w+) regex, I added the ? character for an optional string.

You can use

^[%w%s_-]*%w

It matches

• ^ - start of string
• [%w%s_-]* - zero or more alphanumerics, whitespaces, _ or hyphens
• %w - an alphanumeric char.

See the Lua demo:

local function extract(text)
    return string.match(text, "^[%w%s_-]*%w")
end
 
print(extract("mar_paci (toto totot)"))
-- => mar_paci
print(extract("toi-re/3.9"))
-- => toi-re