low_luajit/lua/
math.rs

1use crate::{LuaState, ffi};
2
3/// Math functions.
4impl LuaState {
5	/// Concatenates the first `n` elements on top of the stack, popping them in the process, and pushes the result at the top.
6	///
7	/// If `n` is `1` or negative, nothing happens. If `n` is `0`, the result is an empty string.
8	///
9	/// # Panics
10	///
11	/// Panics if the stack contains less than `n` values currently.
12	///
13	/// # Lua Errors
14	///
15	/// Some types (like `nil` or `boolean`) may be unable to be concatenated.
16	///
17	/// Concatenating may also trigger the `__concat` metamethod which could error.
18	#[inline]
19	pub fn concat(&mut self, n: i32) {
20		assert!(n <= self.get_top(), "tried to concatenate {n} values but the stack currently holds {} values", self.get_top());
21
22		// SAFETY: self.0 is always valid and the stack contains enough values to pop.
23		unsafe { ffi::lua_concat(self.0, n); }
24	}
25
26	/// Returns the "length" of the value at the given acceptable `index`:
27	/// - Strings return the string's length.
28	/// - Numbers are converted (permanently!) to a string and return the string's length.
29	/// - Tables return the result of the length operator (`#`), bypassing the `__len` metamethod.
30	/// - Userdata returns the size of the allocated block.
31	/// - Anything else will always return 0.
32	#[inline]
33	#[must_use]
34	pub fn object_length(&self, index: i32) -> usize {
35		self.assert_string_index(index);
36
37		// SAFETY: self.0 is always valid.
38		unsafe { ffi::lua_objlen(self.0, index) }
39	}
40
41	/// Returns `true` if the two values at acceptable indices `index1` and `index2` are equal. Returns `false` if they're not equal or invalid.
42	///
43	/// # Lua Errors
44	///
45	/// Comparing may trigger the `__eq` metamethod which could error.
46	///
47	/// To avoid triggering any metamethod, see [`LuaState::raw_equal`].
48	#[inline]
49	#[must_use]
50	pub fn equal(&self, index1: i32, index2: i32) -> bool {
51		// SAFETY: self.0 is always valid.
52		unsafe { ffi::lua_equal(self.0, index1, index2) != 0 }
53	}
54
55	/// Returns `true` if the two values at acceptable indices `index1` and `index2` are equal. Returns `false` if they're not equal or invalid.
56	///
57	/// Unlike [`LuaState::equal`], this function will not trigger the `__eq` metamethod.
58	#[inline]
59	#[must_use]
60	pub fn raw_equal(&self, index1: i32, index2: i32) -> bool {
61		// SAFETY: self.0 is always valid.
62		unsafe { ffi::lua_rawequal(self.0, index1, index2) != 0 }
63	}
64
65	/// Returns `true` if the value at acceptable index `index1` is less than the value at acceptable index `index2`.
66	/// Returns `false` if they're not equal or invalid.
67	///
68	/// # Lua Errors
69	///
70	/// Some types may be incompatible for this comparison (like comparing a `boolean` with a `string`, or `nil` with...anything).
71	///
72	/// Comparing may trigger the `__lt` metamethod which could error.
73	#[inline]
74	#[must_use]
75	pub fn less_than(&self, index1: i32, index2: i32) -> bool {
76		// SAFETY: self.0 is always valid.
77		unsafe { ffi::lua_lessthan(self.0, index1, index2) != 0 }
78	}
79}
low_luajit/lua/math.rs

low_luajit/lua/
math.rs
