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Lua 5.3 adds bitwise operators and floor division to the language.

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Feature Flag

To parse Lua 5.3 syntax, you must enable the lua53 feature flag in your Cargo.toml:
[dependencies]
full_moon = { version = "2.1", features = ["lua53"] }
Note: The lua53 feature automatically enables lua52, so you get goto/label support as well.

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Version-Specific Operators

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Bitwise Binary Operators

Lua 5.3 introduces several bitwise operators as part of BinOp: 
pub enum BinOp {
    // ... other operators
    
    #[cfg(feature = "lua53")]
    Ampersand(TokenReference),        // Bitwise AND: &
    
    #[cfg(feature = "lua53")]
    Pipe(TokenReference),             // Bitwise OR: |
    
    #[cfg(feature = "lua53")]
    Tilde(TokenReference),            // Bitwise XOR: ~
    
    #[cfg(feature = "lua53")]
    DoubleLessThan(TokenReference),   // Left shift: <<
    
    #[cfg(feature = "lua53")]
    DoubleGreaterThan(TokenReference), // Right shift: >>
    
    #[cfg(feature = "lua53")]
    DoubleSlash(TokenReference),      // Floor division: //
}

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Operator Precedence

OperatorPrecedenceDescription
//10Floor division (same as *, /, %)
<<, >>7Bitwise shifts
&6Bitwise AND
~5Bitwise XOR
``4Bitwise OR

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Examples

-- Bitwise AND
local result = 5 & 3  -- 1

-- Bitwise OR
local result = 5 | 3  -- 7

-- Bitwise XOR
local result = 5 ~ 3  -- 6

-- Left shift
local result = 1 << 3  -- 8

-- Right shift
local result = 8 >> 2  -- 2

-- Floor division
local result = 7 // 2  -- 3

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Bitwise NOT (Unary Operator)

Lua 5.3 adds the bitwise NOT operator: 
pub enum UnOp {
    Minus(TokenReference),
    Not(TokenReference),
    Hash(TokenReference),
    
    #[cfg(feature = "lua53")]
    Tilde(TokenReference),  // Bitwise NOT: ~
}

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Example

-- Bitwise NOT
local result = ~5  -- -6 (two's complement)

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Usage

use full_moon::parse;
use full_moon::ast::{BinOp, UnOp};

let ast = parse(r#"
  local x = 5 & 3
  local y = 8 >> 1
  local z = ~x
  local w = 7 // 2
"#)?;

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Inherited Features

Since lua53 enables lua52, you also get:
  • Goto statements and labels (see Lua 5.2)
  • All Lua 5.2 syntax features

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Notes

  • All bitwise operators work on integers
  • The ~ operator serves as both unary bitwise NOT and binary bitwise XOR depending on context
  • Floor division // always rounds toward negative infinity, unlike truncating division /
  • Lua 5.3 also supports integer literals with the 0x prefix and fractional hexadecimal numbers

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