prime.lua: skip colour sequences, add config

Colour sequence skipping is somewhat involved, we might want to
add a helper generator to the "degesch" Lua library, in the form of
{substring, is_formatting}.

formatter_parse_mirc() isn't useful, a pure Lua implementation
would be more appropriate (where do we put that?)
This commit is contained in:
Přemysl Eric Janouch 2020-10-11 16:54:15 +02:00
parent 270d9017e9
commit 7ce1615021
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 34 additions and 16 deletions

View File

@ -15,36 +15,54 @@
-- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
--
local smallest, highlight = 0, "\x1f"
degesch.setup_config {
smallest = {
type = "integer",
default = "0",
comment = "smallest number to scan for primality",
on_change = function (v) smallest = math.max (v, 2) end
},
highlight = {
type = "string",
default = "\"\\x1f\"",
comment = "the attribute to use for highlights",
on_change = function (v) highlight = v end
},
}
-- The prime test is actually very fast, so there is no DoS concern
local is_prime = function (n)
if tonumber (n) < 2 then return false end
for i = 2, n ^ (1 / 2) do if (n % i) == 0 then return false end end
return true
local do_intercolour = function (text)
return tostring (text:gsub ("%f[%w_]%d+", function (n)
if tonumber (n) < smallest then return nil end
for i = 2, n ^ (1 / 2) do if (n % i) == 0 then return nil end end
return highlight .. n .. highlight
end))
end
local do_interlink = function (run)
-- Let's not cripple formatting, colours especially
-- TODO: we can just employ the same approach as in do_text and skip over
if run:find ('%c') then return run end
return run:gsub ("%f[%w_]%d+%f[^%w_]", function (number)
if is_prime (number) then return "\x1f" .. number .. "\x1f" end
return number
end)
local do_interlink = function (text)
local rebuilt, last = {""}, 1
for start in text:gmatch ('()\x03') do
table.insert (rebuilt, do_intercolour (text:sub (last, start - 1)))
local sub = text:sub (start + 1)
last = start + (sub:match ('^%d%d?,%d%d?()') or sub:match ('^%d?%d?()'))
table.insert (rebuilt, text:sub (start, last - 1))
end
return table.concat (rebuilt) .. do_intercolour (text:sub (last))
end
local do_text = function (text)
local do_message = function (text)
local rebuilt, last = {""}, 1
for run, link, endpos in text:gmatch ('(.-)(%f[%g]https?://%g+)()') do
last = endpos
table.insert (rebuilt, do_interlink (run) .. link)
end
return table.concat (rebuilt, "") .. do_interlink (text:sub (last))
return table.concat (rebuilt) .. do_interlink (text:sub (last))
end
-- XXX: sadly it won't typically highlight primes in our own messages,
-- unless IRCv3 echo-message is on
degesch.hook_irc (function (hook, server, line)
local start, message = line:match ("^(.- PRIVMSG .- :)(.*)$")
return message and start .. do_text (message) or line
return message and start .. do_message (message) or line
end)