Crate tinyscript

tinyscript - A small, C-like scripting language

tinyscript is considered to ba a superset of the scripting language defined in BehviorTree.CPP.

Usage

use tinyscript::{Runtime, DefaultEnvironment};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut runtime = Runtime::default();
    let mut env = DefaultEnvironment::default();
    let value = runtime.run("2 * 2 == 4", &mut env)?;
    Ok(())
}

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be dual licensed as above, without any additional terms or conditions.

Data types

Type	Examples
Boolean	true/false
String	‘hello world’
Enum	RED, GREEN, BLUE
Numbers:
Integer	42
Hexadecimal	0x01
Float	3.14

Note: under the hood an Enum is always interpreted as its integer value.

Boolean Values

Boolean values can be one of true or false.

Setting booleans:

val_a = true
val_b := !false

The logical ! works with boolean literals. !false is the equivalent of true. val_a and val_b above are equivalent.

Strings

Strings are enclosed by ‘…’.

Enums

Enums must be registered to the Runtime before they can be used.

Numbers

Negative numbers

Operator	Description
~	Negate

Statements

Examples:

print 42
print 42;
42; print 42; variable:= 42; (13 + 12)

Multiple statements in a single script are separated by a semicolon. The last statements may or may not end with a semicolon.

Assignment operators

Examples:

var_a := 42
var_b = 3.14
message = 'hello world'

• The first line assigns the number 42 to the variable var_a.
• The second line assigns the number 3.14 to the variable var_b.
• The third line assigns the string “hello world” to the variable message.

Arithmetic operators and parenthesis

Examples:

var_a := 7
var_b := 5
var_b *= 2
var_c := (var_a * 3) + var_b

The resulting values of var_a is 10 and var_c is 31.

The following operators are supported:

Operator	Assign Operator	Description
+	+=	Add
-	-=	Subtract
*	*=	Multiply
/	/=	Divide

These operators can be used only on Number data types, only the addition acan also be used on Strings.

Bitwise operators

These operators work only on integer and hexadecimal numbers. Using them with a string or float number will cause an error.

Examples:

value:= 0x7F
val_a:= value & 0x0F
val_b:= value | 0xF0

The value of val_a is 0x0F (or 15); val_b is 0xFF (or 255).

Operator	Description
|	Bitwise or
&	Bitwise and
^	Bitwise xor

Logic and comparison operators

Operators which return a boolean.

Example:

val_a := true
val_b := 5 > 3
val_c := (val_a == val_b)
val_d := (val_a && val_b) || !val_c

Operator	Description
&&	Logic and
||	Logic or
!	Negation
==	Equality
!=	Inequality
<	Less
<=	Less equal
>	Greater
>=	Greater equal

Ternary operator if-then-else

Example:

val_b = (val_a > 1) ? 42 : 24

The implementation follows the pattern of clox as described in Part III of crafting interpreters

Re-exports

pub use error::Error;

pub use execution::Chunk;

pub use runtime::Runtime;

pub use runtime::SharedRuntime;

Modules

compiling

Bytecode compiler for tinyscript

error

tinyscript errors

execution

Virtual Machine of tinyscript

runtime

Runtime environment for tinyscript

Structs

DefaultEnvironment

A very simple default Environment for testing purpose and the REPL

Constants

SHOULD_NOT_HAPPEN

Global constant for expect statements that should never happen

Traits

Environment

The trait for providing an Environment to a VM that stores variables persistently and externally available.

ScriptEnum

The trait for script enums.

Type Aliases

ConstString

An immutable thread safe String type see: Logan Smith.

Derive Macros

ScriptEnum

Derive macro ScriptEnum. Enables a Rust enum to be used in a ‘C’ like mannner within the tinyscript language.