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-rw-r--r--plugins/xC/prime.lua68
1 files changed, 68 insertions, 0 deletions
diff --git a/plugins/xC/prime.lua b/plugins/xC/prime.lua
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+++ b/plugins/xC/prime.lua
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+--
+-- prime.lua: highlight prime numbers in messages
+--
+-- Copyright (c) 2020, Přemysl Eric Janouch <p@janouch.name>
+--
+-- Permission to use, copy, modify, and/or distribute this software for any
+-- purpose with or without fee is hereby granted.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+-- SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+-- OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+-- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+--
+
+local smallest, highlight = 0, "\x1f"
+xC.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 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 (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_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))
+end
+
+-- XXX: sadly it won't typically highlight primes in our own messages,
+-- unless IRCv3 echo-message is on
+xC.hook_irc (function (hook, server, line)
+ local start, message = line:match ("^(.- PRIVMSG .- :)(.*)$")
+ return message and start .. do_message (message) or line
+end)