Standard Library Overview

Tova provides 220+ built-in functions that are automatically available in every Tova program. There is nothing to import -- all standard library functions are in scope by default.

Availability

Standard library functions work everywhere Tova code runs:

• tova run -- all functions available in scripts and the REPL
• Server code -- all functions available in route handlers and server modules
• Client code -- functions are tree-shaken so only the ones you actually use are included in the browser bundle

Design Philosophy

Tova's standard library follows a few guiding principles:

• Functional style -- most functions take data as the first argument and return new values rather than mutating
• Result and Option types -- instead of throw and try/catch, Tova uses Ok/Err and Some/None for principled error handling
• Pipeable -- every function works naturally with the pipe operator |>
• Method syntax -- many functions (especially string functions) can be called as methods: "hello".upper() is the same as upper("hello")

Categories at a Glance

Category	Functions	Page
Collections	len, range, filled, enumerate, sum, sorted, reversed, zip, min, max, type_of, filter, map, find, find_index, includes, any, all, flat_map, reduce, unique, group_by, chunk, flatten, take, drop, first, last, count, partition, print, zip_with, frequencies, scan, min_by, max_by, sum_by, product, sliding_window, intersection, difference, symmetric_difference, is_subset, is_superset, union, pairwise, combinations, permutations, intersperse, interleave, repeat_value, binary_search, is_sorted, compact, rotate, insert_at, remove_at, update_at, parallel_map	Collections
Strings	trim, trim_start, trim_end, split, join, replace, replace_first, repeat, upper, lower, contains, starts_with, ends_with, chars, words, lines, char_at, pad_start, pad_end, capitalize, title_case, snake_case, camel_case, kebab_case, index_of, last_index_of, count_of, substr, reverse_str, center, is_empty, truncate, word_wrap, dedent, indent_str, slugify, escape_html, unescape_html, fmt	Strings
Math & Stats	PI, E, INF, abs, floor, ceil, round, trunc, sign, clamp, sqrt, pow, sin, cos, tan, asin, acos, atan, atan2, log, log2, log10, exp, is_nan, is_finite, is_close, to_radians, to_degrees, gcd, lcm, factorial, random, random_int, random_float, choice, sample, shuffle, sleep, hypot, lerp, divmod, avg, mean, median, mode, stdev, variance, percentile, format_number, to_hex, to_binary, to_octal, to_fixed, typed_sum, typed_dot, typed_norm, typed_add, typed_scale, typed_map, typed_reduce, typed_sort, typed_zeros, typed_ones, typed_fill, typed_range, typed_linspace	Math & Stats
Objects & Utilities	keys, values, entries, merge, freeze, clone, has_key, get, from_entries, pick, omit, map_values	Objects & Utilities
Functional	compose, pipe_fn, identity, memoize, debounce, throttle, once, negate, partial, curry, flip	Functional
Regex	regex_test, regex_match, regex_find_all, regex_replace, regex_split, regex_capture, regex_builder	Regex
Validation	is_email, is_url, is_numeric, is_alpha, is_alphanumeric, is_uuid, is_hex	Validation
URL & UUID	uuid, parse_url, build_url, parse_query, build_query	URL & UUID
Date & Time	now, now_iso, date_parse, date_format, date_add, date_diff, date_from, date_part, time_ago	Date & Time
JSON	json_parse, json_stringify, json_pretty	JSON
Encoding	base64_encode, base64_decode, url_encode, url_decode, hex_encode, hex_decode	Encoding
Async & Error Handling	try_fn, try_async, parallel, race, timeout, retry, sleep	Async & Error Handling
Result & Option	Ok, Err, Some, None, ? (propagation), filter_ok, filter_err	Result & Option
Type Conversion	to_int, to_float, to_string, to_bool	Type Conversion
Assertions	assert, assert_eq, assert_ne, assert_throws, assert_snapshot	Assertions
Lazy Iterators	iter, Seq.filter, Seq.map, Seq.take, Seq.drop, Seq.zip, Seq.flat_map, Seq.enumerate, Seq.collect, Seq.reduce, Seq.first, Seq.count, Seq.forEach, Seq.any, Seq.all, Seq.find	Lazy Iterators
Advanced Collections	OrderedDict, DefaultDict, Counter, Deque	Advanced Collections
Channels	Channel.new, ch.send, ch.receive, ch.close	Channels
Terminal & CLI	color, green, red, yellow, blue, cyan, magenta, gray, bold, dim, underline, strikethrough, table, panel, progress, spin, ask, confirm, choose, choose_many, secret	Terminal & CLI
Scripting I/O	fs.exists, fs.read_text, fs.write_text, fs.ls, fs.mkdir, fs.rm, fs.glob_files, sh, exec, spawn, env, args, parse_args, exit, path_join, path_basename, path_dirname	Scripting I/O
Tables	Table, where, select, derive, sort_by, group_by, agg, join, pivot, unpivot, explode, peek, describe	Tables
Testing	Gen.int, Gen.float, Gen.bool, Gen.string, Gen.array, Gen.oneOf, forAll, create_spy, create_mock	Testing

Quick Reference

I/O

print("Hello, World!")
print("Name:", name, "Age:", age)

Collections

len([1, 2, 3])                  // 3
range(5)                         // [0, 1, 2, 3, 4]
sorted([3, 1, 2])               // [1, 2, 3]
zip([1, 2], ["a", "b"])         // [[1, "a"], [2, "b"]]
unique([1, 2, 2, 3])            // [1, 2, 3]

Strings

upper("hello")                   // "HELLO"
split("a,b,c", ",")             // ["a", "b", "c"]
"hello".contains("ell")         // true

Math

abs(-5)                          // 5
clamp(15, 0, 10)                // 10
sqrt(16)                         // 4

Objects

keys({ a: 1, b: 2 })           // ["a", "b"]
merge({ a: 1 }, { b: 2 })      // { a: 1, b: 2 }
get(user, "address.city")       // safe nested access
pick(obj, ["name", "email"])    // select keys

Functional

double_then_inc = compose(fn(x) x + 1, fn(x) x * 2)
cached = memoize(expensive_fn)
run_once = once(fn() init_app())

JSON & Encoding

json_parse('{"a": 1}')          // Ok({ a: 1 })
json_pretty({ a: 1 })           // formatted JSON string
base64_encode("hello")          // "aGVsbG8="
url_encode("hello world")       // "hello%20world"

Regex

regex_test("hello123", "\\d+")         // true
regex_replace("a1b2c3", "\\d", "X")   // "aXbXcX"
regex_find_all("a1b2c3", "\\d")        // [{match: "1"}, ...]

Validation

is_email("user@example.com")           // true
is_url("https://tova.dev")            // true
is_uuid("550e8400-e29b-41d4-a716-446655440000")  // true

URL & UUID

id = uuid()                             // "a1b2c3d4-..."
parse_query("a=1&b=2")                 // { a: "1", b: "2" }
build_url({ host: "api.com", pathname: "/v1" })

Date & Time

d = date_parse("2024-01-15")           // Ok(Date)
date_format(d.unwrap(), "YYYY-MM-DD")  // "2024-01-15"
date_add(d.unwrap(), 7, "days")        // Date (7 days later)
time_ago(d.unwrap())                    // "3 months ago"

Async & Error Handling

result = try_fn(fn() risky_operation())
data = await parallel([fetch("/a"), fetch("/b")])
data = await retry(fn() fetch("/api"), { times: 3 })

Result & Option

result = Ok(42)
result.map(fn(x) x * 2)        // Ok(84)
result.unwrap()                  // 42

option = Some("hello")
option.unwrapOr("default")      // "hello"
None.unwrapOr("default")        // "default"

Terminal & CLI

print(green("Success: ") + bold("All tests passed"))
print(table(data, { headers: ["Name", "Score"] }))
name = await ask("What is your name?")
ok = await confirm("Deploy to production?")

Assertions

assert(len(items) > 0, "items must not be empty")
assert_eq(add(2, 3), 5)

Using with Pipes

All standard library functions are designed to work with the pipe operator |>:

[1, 2, 3, 4, 5]
  |> filter(fn(x) x > 2)
  |> map(fn(x) x * 10)
  |> sum()
// 120

"Hello, World"
  |> lower()
  |> split(", ")
  |> first()
// "hello"