Notation
The syntax is specified using Extended Backus-Naur Form (EBNF).
Productions
production_name = expression .Productions are expressions terminated by ..
Operators
| Notation | Meaning |
|---|---|
a b | Sequence |
a | b | Alternation |
[ a ] | Optional (0 or 1) |
{ a } | Repetition (0 or more) |
( a ) | Grouping |
"x" | Literal keyword |
'c' | Literal character |
'a' … 'z' | Character range (inclusive) |
Naming
| Style | Usage |
|---|---|
lower_case | Production names |
PascalCase | Type names |
snake_case | Functions, variables |
Terminology
| Term | Meaning |
|---|---|
| must | Absolute requirement |
| must not | Absolute prohibition |
| may | Optional |
| error | Compile-time failure |
| panic | Run-time failure |
Examples
Valid:
@add (a: int, b: int) -> int = a + bInvalid:
@add (a: int, b: int) = a + b // error: missing return type