Quick Reference

The tables below are for looking something up at a glance. For the exact shape of every construct, see the Grammar.

Keywords

Keyword	Purpose
class	Declare a class
interface	Declare an interface
enum	Declare an enum
fn	Declare a function or method
extends	Inherit from a class
implements	Fulfill one or more interfaces
super	Call the parent’s init
self	Reference the current instance
static	Declare a class-level member
local	Declare a private member or variable
export	Make a file member publicly importable
import	Import from another file
return	Return a value from a function
throw	Raise an error
try	Begin an error-handled block
catch	Handle a thrown error; several clauses are tried in order
finally	Run on every way out of a try
for	Begin a loop
while	Begin a while loop
repeat	Begin a repeat-until loop
until	End condition for repeat loop
break	Exit a loop
continue	Skip to the next iteration
if / elseif / else / end	Conditional logic
match	Begin a pattern-matching expression
case	Introduce a pattern arm inside match
when	Attach a guard condition to a case, or start a when(...) pipeline
then	Begin a match arm body / if branch
nil	Absence of value
true / false	Boolean literals

Literals

Literal	Type	Notes
42	integer
0xFF, 0b1010	integer	_ may separate digits: 0xFF_80_00
3.14	float
.5	float	The integer part may be omitted
10f, 10F	float	Suffix form of 10.0
1e9, 2e-7, 6.022E+23	float	Exponent: ×10ⁿ, always a float
"text"	string
true, false	boolean
nil	—	Only assignable to a nullable (T?) slot

Operators

Operator	Meaning
?.	Safe member access
?[ ]	Safe index
??	Null coalescing fallback
!	Force unwrap nullable
..	String concatenation
#	Length of a table, string (codepoints) or bytes (bytes)
==, !=	Equality checks
>, <, >=, <=	Comparisons
and, or, not	Boolean logic
+, -, *, /, %	Arithmetic (/ on two integers truncates)
^	Exponentiation (right-associative, binds tighter than unary -)
&, |, ~, <<, >>	Bitwise and / or / xor / shifts — integer only
~a	Bitwise complement (prefix ~; infix ~ is xor)
+=, -=, *=, /=, %=, ^=, ..=, &=, |=, <<=, >>=	Compound assignment (no ~= — that is Lua’s !=)
:	Pipeline stage call inside when(...)
as	Cast — converts a typed value (x as integer truncates toward zero, n as string renders), tests an any

Coroutines

Form	Meaning
Coroutine.create(fn(co) … end)	A new, not-yet-started Coroutine<T>; co is its Yielder<T>
co.yield(v)	Suspend, handing v to whoever resumed
gen.resume()	Run to the next yield; T?, nil once done or failed
for v in gen do … end	Resume until finished; v is a T
gen.status()	"suspended", "running", "normal" or "dead"
gen.isDone() / gen.error()	Dead yet? / Why it failed, or nil