Tya Guide

Tya is a small indentation-based dynamic language inspired by CoffeeScript. This guide is for reading from top to bottom.

Run A Program

tya run examples/hello.tya

tya run builds a temporary executable, runs it, and removes the temporary file. This is the normal way to run a Tya program during development.

To keep the executable, use tya build.

tya build examples/hello.tya
./hello

Without -o, tya build writes an executable named after the input file basename in the current directory. Use -o to choose the output path.

tya build examples/hello.tya -o bin/hello

To print the installed Tya version:

tya version

name = "Tya"
age = 1
pi = 3.14
ready = true
missing = nil

Strings can contain interpolated expressions.

print "Hello, {name}"

Use snake_case for variables, functions, modules, dictionary keys, and module members. Use SCREAMING_SNAKE_CASE for constants.

user_name = "komagata"
MAX_COUNT = 10

See docs/NAMING.md for the full naming rules.

if age >= 20
  print "adult"
elseif age >= 13
  print "teen"
else
  print "young"

Use and, or, and not for logic.

if ready and not missing
  print "ok"

count = 0
while count < 3
  print count
  count = count + 1

items = ["a", "b"]

for item in items
  print item

for item, index in items
  print "{index}: {item}"

Use of to iterate dictionary keys and values.

user = { name: "komagata", age: 20 }

for key, value of user
  print "{key}: {value}"

Functions use ->. The last expression is returned implicitly.

greet = name -> "Hello, {name}"

print greet "Tya"

Use an indented body for multiple statements.

double = value ->
  result = value * 2
  result

Use return when returning early or returning multiple values.

parse_user = text ->
  if text == ""
    return nil, error "empty user"
  return { name: text }, nil

items = [1, 2]
push items, 3
print items[0]

user = { name: "komagata", age: 20 }

print user["name"]

Use index access for dictionaries. Dictionary member access is not part of Tya v0.1.

Tya uses error values, not exceptions.

user, err = parse_user ""
if err
  print err["message"]

Inside a function, try propagates the error part of a value, err result.

load_user = text ->
  user = try parse_user(text)
  user["name"]

Import another .tya file from the same directory.

import greeting

print greeting.hello("komagata")

Each module file defines exactly one top-level module. The module name must match the file name.

# greeting.tya
module greeting
  hello = name -> "Hello, {name}"

See docs/API.md for v0.1 built-in functions such as print, len, read_file, and to_string.