Jule Manual

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Keywords ​

Keywords are the building blocks that make up your program. They are the root words of the language and the common essential words used when expressing the program.

Keywords have been pre-reserved in the language and are not allowed to be used as identifiers.

List of Keywords

jule
map      type      impl        self
trait    struct    enum        fn
const    let       mut         for
in       break     continue    goto
match    fall      if          else
ret      error     use         co
extern   unsafe    defer       chan
select   async     await

Imaginary Keywords ​

Imaginary keywords are words that are not keywords for Jule, but are recommended for developers to treat as if they were keywords. These words are mostly aliases for built-in types, reserved names for some functions, or constant variables.

Developers can use these words as identifiers to functions and other definitions if they wish, but this can lead to a variety of development issues and readability challenges. Because the relevant word now points to a new definition defined by the developer instead of its commonly used built-in definition.

For example:

jule
type int: str

fn main() {
    let a: int = "hello world"
    println(a)
}

As seen in the example above, the variable a is defined as int type. At first glance, the variable a may be thought to be an integer, but the identifier int has been redefined for an alias and corresponds to the type str. Therefore, the type a is str, not int.

List of Imaginary Keywords

jule
int        uint       uintptr     i8
i16        i32        i64         u8
u16        u32        u64         f32
f64        cmplx64    cmplx128    bool
str        any        rune        byte
true       false      nil         iota
print      println    panic       make
copy       append     len         cap
delete     new        close       real
imag       cmplx

INFO

According to Jule's public modifier rules, no reserved keyword can be public. So if you want to use a reserved keyword as an identifier, this would be a name used only within this package, will not be exported for public use.