Variable

Function

variable is used to name the value for subsequent reading, modification and transfer. BT is a dynamically typed language, and variables can be reassigned to different types of values during runtime.

Syntax

Naming rules

Rules	Description
The first character	can be lowercase English letters, `_` or `$`, and cannot be numbers or uppercase letters.
The following characters	can be English letters, numbers, `_` or `$`.
Case	Case-sensitive, `name` and `Name` have different meanings.

Names matching [A-Z][A-Za-z0-9_]* will be recognized as constants, such as Name, Config, NAME, Name_1. If the first letter is capitalized but contains $, such as User$, an error will be reported directly.

let local declaration

let is used to declare local variables within the current function. The uninitialized variable value is empty. let is only a variable and cannot be used to declare constants.

Return Value

Type	Description
Any	Assignment expression returns the value of the expression on the right.

Code Examples

Notes

Multiple statements can be written on new lines or separated by commas.
first second third This null declaration initializes the variable to empty.

- Variable names cannot begin with a capital letter; use constant naming rules when non-rewritable bindings are required, and define them directly with assignment syntax.