Native modules

local json = require("json")
local crypto = require("crypto")
 
print(json.encode({ ok = true }))           --> {"ok":true}
print(crypto.sha256("hello"):sub(1, 16))    --> 2cf24dba5fb0a30e

local crypto = require("crypto")
print(crypto.sha256(42))

luascript: Type "number" could not be converted into "string" at line 2

local json = require("json")
 
print(json.encode({ name = "ada", tags = { "x", "y" } }))
--> {"name":"ada","tags":["x","y"]}
 
local t = json.decode('{"id": 7, "score": 9.5, "tags": ["a", "b"]}')
print(t.id, math.type(t.id), t.score, #t.tags)   --> 7	integer	9.5	2
 
print(json.encode({ items = json.empty_array }))  --> {"items":[]}
 
-- Without the sentinel, a null inside an array would truncate it.
local arr = json.decode("[1, null, 3]", { null = json.null })
print(#arr, arr[2] == json.null)                  --> 3	true
 
print(json.encode({ a = 1 }, { indent = 2 }))
--> {
-->   "a": 1
--> }

local http = require("http")
 
-- No network needed.
print(http.encode_url({ q = "lua script", page = 2 }))   --> page=2&q=lua+script
print(http.encode_url({ tag = { "a", "b" } }))           --> tag=a&tag=b
 
-- Network calls raise on transport errors, so guard them.
local ok, res = pcall(http.get, "https://httpbin.org/get", { timeout = 5 })
if ok and res.ok then
    print(res.status, #res.body)
else
    print("request failed:", ok and res.status or res)
end
 
local api = http.new_client({
    base_url = "https://httpbin.org",
    headers = { ["User-Agent"] = "luascript-docs" },
    timeout = 5,
})
local ok2, r = pcall(function()
    return api:post("/post", nil, { json = { name = "ada" } })
end)
if ok2 then print(r.status, r.headers["Content-Type"]) end

local httpserver = require("httpserver")
local json = require("json")
 
local server = httpserver.new()
local hits = 0
 
local function index(req)
    return "hello from " .. req.path          -- a string means 200 text/plain
end
 
local function stats(req)
    hits += 1                                 -- no lock needed: handlers are serialised
    return {
        status = 200,
        headers = { ["Content-Type"] = "application/json" },
        body = json.encode({ hits = hits }),
    }
end
 
server:get("/", index)
server:get("/stats", stats)
server:route("PUT", "/item", function(req) return { status = 204, body = "" } end)
server:set_not_found(function(req)
    return { status = 404, body = "no route for " .. req.method .. " " .. req.path }
end)
 
print(index({ method = "GET", path = "/" }))          --> hello from /
print(stats({ method = "GET", path = "/stats" }).body) --> {"hits":1}
 
if os.getenv("SERVE") then
    server:listen(":8080")   -- blocks until server:stop()
end

local crypto = require("crypto")
 
print(crypto.sha256("hello"))
--> 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824
 
local mac = crypto.hmac_sha256("secret", "message")
print(crypto.hmac_verify("secret", "message", mac))   --> true
 
local stored = crypto.password_hash("hunter2")
print(stored:sub(1, 9))                               --> $argon2id
print(crypto.password_verify("hunter2", stored),
      crypto.password_verify("wrong", stored))        --> true	false
 
local token = crypto.hex_encode(crypto.random_bytes(16))
print(#token)                                         --> 32
print(crypto.base64url_encode("hi?"), crypto.base64_decode("aGk/"))   --> aGk_	hi?

local uuid = require("uuid")
local id = uuid.v4()
print(id)                                        --> 51367656-de78-4bae-9815-69228ad0174e (random)
print(uuid.is_valid(id), uuid.is_valid("nope"))  --> true	false

local regexp = require("regexp")
 
local email = regexp.compile([[(\w+)@(\w+)\.com]])
print(email:test("mail ada@example.com today"))   --> true
print(email:capture("ada@example.com"))           --> ada@example.com	ada	example
 
local date = regexp.compile([[(?P<year>\d{4})-(?P<month>\d{2})]])
local g = date:groups("released 2026-10")
print(g.year, g.month)                            --> 2026	10
 
local num = regexp.compile([[\d+]])
print(table.concat(num:find_all("a1 b22 c333"), ","))   --> 1,22,333
print(num:replace("a1 b22", "<$0>"))                    --> a<1> b<22>
print(num:replace_func("a1 b22", function(m) return ("#"):rep(#m) end))   --> a# b##
print(table.concat(regexp.compile([[\s*,\s*]]):split("a , b,c"), "|"))     --> a|b|c
print(regexp.quote("1+1=2?"), regexp.is_valid("(unclosed"))               --> 1\+1=2\?	false

local time = require("time")
 
local t = time.parse_utc(time.DATE, "2026-01-31")
print(t)                                       --> 1769817600
print(time.format(t, time.DATETIME, true))     --> 2026-01-31 00:00:00
print(time.format(t, "%Y/%m/%d", true))        --> 2026/01/31
print(pcall(time.parse, "%Y-%m-%d", "2026-01-31"))   --> false	... cannot parse ...
 
local d = time.date(t, true)
print(d.year, d.month, d.day, d.wday)          --> 2026	1	31	7
 
local start = time.clock()
time.sleep(0.01)
print(time.clock() - start >= 0.01)            --> true

local sort = require("sort")
 
local people = {
    { name = "ada", age = 36 }, { name = "bob", age = 25 }, { name = "cy", age = 36 },
}
sort.stable(people, function(a, b) return a.age > b.age end)
for _, p in ipairs(people) do io.write(p.name, " ") end
print()                                        --> ada cy bob
 
local t = sort.sort({ 5, 2, 9, 1 })
print(table.concat(t, ","), sort.is_sorted(t)) --> 1,2,5,9	true
print(table.concat(sort.reverse(t), ","))      --> 9,5,2,1

local std = require("std")
 
local s = std.new_stack()
s:push(1); s:push(2)
print(s:pop(), s:size())                       --> 2	1
 
local d = std.new_deque()
d:push_back("b"); d:push_front("a")
print(d:front(), d:back())                     --> a	b
 
local seen = std.new_set()
print(seen:add("x"), seen:add("x"), seen:contains("x"))   --> true	false	true
 
local h = std.new_heap(function(a, b) return a < b end)   -- min-heap
for _, v in ipairs({ 5, 1, 4 }) do h:push(v) end
print(h:pop(), h:pop(), h:top())               --> 1	4	5
 
local t = std.new_trie()
t:insert("car", "cart")
print(t:find("car"), t:find("ca"), t:size())   --> true	false	2
 
local b = std.new_btree()
b:insert(30, 10, 20)                           -- every argument is a key
print(b:min(), b:max(), b:search(20))          --> 10	30	true

local compression = require("compression")
 
local text = ("hello luascript "):rep(100)
local packed = compression.gzip_encode(text)
print(#text, #packed, compression.gzip_decode(packed) == text)   --> 1600	50	true
print(compression.zlib_decode(compression.zlib_encode(text)) == text)   --> true
 
print(compression.rle_decode(compression.rle_encode("aaabccdddd")))     --> aaabccdddd
print(compression.decode(compression.encode("abracadabra")))           --> abracadabra

local compression = require("compression")
local text = ("hello luascript "):rep(100)
local small = compression.gzip_encode(text, 9)
print(#small, compression.gzip_decode(small) == text)   --> 50	true
 
local enc = compression.encode("abracadabra")
print(enc.bits, compression.decode(enc))               --> 01101110100010101101110	abracadabra

local bit32 = require("bit32")
print(bit32.band(0xF0, 0x3C), bit32.bor(1, 2, 4), bit32.bxor(0xFF, 0x0F))   --> 48	7	240
print(bit32.bnot(0))                           --> 4294967295
print(bit32.lrotate(0x80000001, 1))            --> 3
print(bit32.extract(0xFF00, 8, 8), bit32.replace(0, 5, 4, 3))   --> 255	80
print(string.format("%08x", bit32.bswap(0x11223344)))           --> 44332211
print(~0)                                      --> -1   (native operators are 64-bit)

local log = require("log")
 
log.set_output("stdout")       -- default is stderr
log.set_prefix("worker")
log.info("started", 3, "jobs")
log.debug("hidden: below the default info threshold")
log.set_level("debug")
log.debug("now visible")
print(log.get_level(), log.LEVELS.warn)

2026-10-11T22:02:10 [INFO] worker started	3	jobs
2026-10-11T22:02:10 [DEBUG] worker now visible
debug	3

local debug = require("debug")
 
local function inner()
    print(debug.traceback("checkpoint"))
end
local function outer() inner() end
outer()
 
local info = debug.getinfo(outer)
print(info.what, info.nparams, info.short_src)

checkpoint
stack traceback:
	debug.lsc:4: in function 'inner'
	debug.lsc:6: in function 'outer'
	debug.lsc:7: in main chunk
Lua	0	debug.lsc

local db = require("db")
print(table.concat(db.drivers(), ", "))   --> mssql, mysql, postgres, sqlite, sqlserver
 
local conn = db.open("sqlite", ":memory:")
conn:exec("CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT, age INTEGER)")
 
local affected, id = conn:exec("INSERT INTO users (name, age) VALUES (?, ?)", "ada", 36)
conn:exec("INSERT INTO users (name, age) VALUES (?, ?)", "bob", 25)
print(affected, id)                       --> 1	1
 
local p = conn:placeholder(1)
local rows = conn:query("SELECT id, name, age FROM users WHERE age > " .. p, 30)
for _, r in ipairs(rows) do print(r.id, r.name, r.age) end   --> 1	ada	36
 
print(conn.driver, db.placeholder("postgres", 2), db.placeholder("sqlserver", 1))
--> sqlite	$2	@p1
conn:close()

print(os.platform, os.arch, os.path_separator)   --> windows	amd64	\   (varies)
print(os.date("!%Y-%m-%d", 0))                   --> 1970-01-01
 
-- LuaScript has no octal literals: 0644 is decimal 644.
-- Write tonumber("644", 8), or its decimal value 420.
local f = os.open("demo.bin", os.o_rdwr | os.o_create | os.o_trunc, 420)
f:write("hello world")
f:seek(0, os.seek_set)
print(f:read(5), f:stat().size)                  --> hello	11
f:truncate(5)
f:close()
 
print(os.rename("demo.bin", "demo2.bin"))        --> true
print(os.remove("demo2.bin"))                    --> true

local f = assert(io.open("notes.txt", "w"))
f:write("one\n", "two\n"):write("three\n")     -- write returns the handle
f:close()
 
for line in io.lines("notes.txt") do io.write("[", line, "] ") end
print()                                        --> [one] [two] [three]
 
local r = assert(io.open("notes.txt", "r"))
print(r:read("l"), r:seek("end"))              --> one	14
r:close()
print(io.type(r), io.type(io.stdout))          --> closed file	file
os.remove("notes.txt")

local handle
do
    local f <close> = assert(io.open("log.txt", "w"))
    f:write("saved\n")
    handle = f
end                                            -- f is closed here
print(io.type(handle))                         --> closed file
print(io.lines("log.txt")())                   --> saved
os.remove("log.txt")

go run -tags luascript_ui ./cmd/luascript examples/31_ui_module.lsc

local ui = require("ui")
 
local label = ui.new_label("Type your name and click Greet.")
local entry = ui.new_entry("name")
local greet = ui.new_button("Greet")
greet:on_click(function()
    label:set_text(`Hello, {entry:get_text()}!`)
end)
 
local win = ui.new_window("greeter", 360, 200)
win:set_content(ui.new_vbox({ label, entry, greet }))
win:show()
ui.run()          -- blocks until the last window closes

local plugin = require("plugin")
 
if not plugin.supported then
    print("plugins unavailable:", plugin.unsupported_reason())
    return
end
 
local strutil = plugin.generate("strutil", {
    packages  = { { name = "strings" } },
    functions = { { pkg = "strings", name = "ToUpper", as = "Upper" } },
})
print(strutil.Upper("hi"))     -- HI (Linux, macOS and FreeBSD only)