lumars 1.13.0-alpha.1
A high level, lightweight LUA library.
To use this package, run the following command in your project's root directory:
Manual usage
Put the following dependency into your project's dependences section:
Overview
Lumars is a high-level wrapper around LUA 5.1 that aims to be lightweight while providing high quality of life features.
This library has been in use for a while, and is relatively stable. If you can be bothered, please open an issue alongside a minimised, idependent snippet of code that I can add as a unittest, which will also make it easier for me to debug.
Also if you're using this library for a project, consider adding it (or asking me to add it) to the Projects section.
- Overview
- Features
- Quick Start
- Hello World
- Tables
- Functions
- Structs
- Executing a string or file with a different _G table
- nogc strings
- EmmyLua Annotations (IDE autocomplete)
- Nullable support
- Tuple support
- Projects
- Contributing
Features
- Statically linked
- Bundled with prebuilt binaries for LuaJit for Windows, Linux, and MacOS (including Apple Silicon)
- Dynamic values using TaggedAlgebraic
- Ability to convert most D and Lua types to eachother (including structs)
- Provides a high level interface, but also allows manual manipulation of the stack
- Uses a struct-based API instead of classes, to minimise GC usage
- Some types use ref counting in order to be easy to move around while still keeping lifetime guarentees
- Doesn't shy away from the GC, but does try to minimise usage of it
- For example, if you don't mind managing the lifetime of a Lua stack variable, you can use
const(char)[]
instead ofstring
to avoid copying strings onto the GC. - Supports Lua 5.1 (mainly for LuaJit)
- Bind Lua functions to statically typed D functions
- Lambdas, functions, and delegates can all be exposed to Lua
- Utilities to generated EmmyLua-notated lua files for IDE autocomplete
Quick Start
Hello World
Create a new LuaState
, passing in null
so a new state is created. This struct is non-copyable so you might want to put it on the GC heap.
import lumars;
void main()
{
auto l = LuaState(null); // Or `new LuaState`
// openlibs is automatically called
l.doString(`print("Hello, world!")`);
}
Here's another way by using the built-in print
function.
import lumars;
void main()
{
auto l = LuaState(null);
auto print = l.globalTable.get!LuaFunc("print");
print.pcall!0("Hello, world!");
// !0 means "no return results"
}
And here's *another- way where we bind the Lua function into a D function:
import lumars;
void main()
{
auto l = LuaState(null);
auto print = l.globalTable.get!LuaFunc("print").bind!(void, string);
print("Hello, world!");
// If you want to pass it around like a D func:
alias Func = void delegate(string);
Func f = &print.asDelegate;
}
Tables
New Table
import lumars;
void main()
{
auto l = LuaState(null);
auto t = LuaTable.makeNew(&l);
t["a"] = "bc";
t[1] = 23;
assert(t.get!string("a") == "bc");
assert(t.get!int(1) == 23);
}
Iterate with ipairs
import std.conv : to;
auto l = LuaState(null);
l.doString(`t = { 1, 2, 3 }`);
auto t = l.globalTable.get!LuaTable("t");
auto sum = 0;
t.ipairs!((i, /*LuaValue*/ v)
{
sum += v.value!LuaNumber.to!int; // LuaNumber is `double`
});
assert(sum == 6);
Iterate with statically typed ipairs
auto l = LuaState(null);
l.doString(`t = { 1, 2, 3 }`);
auto t = l.globalTable.get!LuaTable("t");
t.ipairs!(int, (i, /*int*/ v)
{
assert(i == v);
});
Iterate with pairs
auto l = LuaState(null);
l.doString(`t = { a = "bc", [1] = 23 }`);
auto t = l.globalTable.get!LuaTable("t");
t.pairs!((k, v) // Both are LuaValue
{
if(k.isText && k.value!string == "a")
assert(v.value!string == "bc");
else if(k.isNumber && k.value!LuaNumber == 1)
assert(v.value!LuaNumber == 23);
else
assert(false);
});
Iterate with statically typed pairs
auto l = LuaState(null);
l.doString(`t = { a = "bc", easy = 123 }`);
auto t = l.globalTable.get!LuaTable("t");
t.pairs!(string, LuaValue, (/*string*/ k, /*LuaValue*/ v)
{
if(k == "a")
assert(v.value!string == "bc");
else if(k == "easy")
assert(v.value!LuaNumber == 123);
else
assert(false);
});
Array conversion
auto l = LuaState(null);
l.doString(`t = { 1, 2, 3, 4, 5 }`);
auto arr = l.globalTable.get!(int[])("t");
assert(arr == [1, 2, 3, 4, 5]);
Functions
Echo
auto l = LuaState(null);
auto t = LuaTable.makeNew(&l);
t["echo"] = (string text){ writeln(text); };
auto f = t.get!LuaFunc("echo").bind!(void, string);
f("Hello, World!");
Echo (Variadic)
auto l = LuaState(null);
l.globalTable["echo"] = (LuaVariadic args) { foreach(arg; args) writeln(arg); };
l.doString(`echo("Henlo", "Warld!", 420, true)`);
Mapping function
import std.conv : to;
auto l = LuaState(null);
int[] map(int[] input, LuaFunc mapper)
{
foreach(ref num; input)
{
LuaValue[1] result = mapper.pcall!1(num);
num = result[0].value!LuaNumber.to!int; // Lua numbers are doubles
}
return input;
}
l.globalTable["map"] = ↦
l.doString(`
local values = {1, 2, 3}
local func = function(n) return n - 2 end
local result = map(values, func)
assert(result[1] == 2 and result[2] == 4 and result[3] == 6)
`);
Overloaded functions
auto lua = new LuaState(null);
lua.register!(
luaOverloads!(
(int a) { assert(a == 1); },
(string a) { assert(a == "2"); },
(int a, string b) { assert(a == 1); assert(b == "2"); }
)
)("overloaded");
lua.doString(`
overloaded(1)
overloaded("2")
overloaded(1, "2")
`);
Returning multiple values (statically)
A way of returning multiple values in a statically typed way, is to use std.typecons.Tuple
as your return value:
import std.typecons : tuple
auto multiReturn()
{
return tuple(20, "40", true);
}
auto lua = new LuaState(null);
lua.register!multiReturn("multiReturn");
lua.doString(`
local i, s, b = multiReturn()
assert(i == 20)
assert(s == "40")
assert(b)
`);
Returning multiple values (dynamically)
A way of returning multiple values in a dynamically typed way, is to use LuaVariadic
as your return value:
LuaVariadic multiReturn()
{
return LuaVariadic([LuaValue(20), LuaValue("40"), LuaValue(true)]);
}
auto lua = new LuaState(null);
lua.register!multiReturn("multiReturn");
lua.doString(`
local i, s, b = multiReturn()
assert(i == 20)
assert(s == "40")
assert(b)
`);
Registering a library
You can use the LuaState.register
function to easily create a Lua table full of functions (a.k.a a Library)
Here's two examples:
import lumars, api, std.path, std.file, std.array;
void registerPathApi(LuaState* lua)
{
lua.register!(
"absolutePath", (string path, string base) => absolutePath(path, base),
"absolutePathCwd", (string path) => absolutePath(path),
"buildPath", (string[] paths) => buildNormalizedPath(paths),
"defaultExtension", (string path, string ext) => defaultExtension(path, ext),
"dirName", (string path) => dirName(path),
"expandTilde", (string path) => expandTilde(path),
"extension", (string path) => extension(path),
"getcwd", () => getcwd(),
"globMatch", (string path, string patt) => globMatch(path, patt),
"isAbsolute", (string path) => isAbsolute(path),
"isValidFilename", (string filename) => isValidFilename(filename),
"isValidPath", (string path) => isValidPath(path),
"normalisePath", (string path) => asNormalizedPath(path).array,
"relativePath", (string path, string base) => relativePath(path, base),
"relativePathCwd", (string path) => relativePath(path),
"setExtension", (string path, string ext) => setExtension(path, ext),
"stripExtension", (string path) => stripExtension(path)
)("sh.path");
}
import lumars, api, std.file, std.exception, std.conv, std.algorithm, std.array;
void registerFsApi(LuaState* lua)
{
lua.register!(
"append", (LuaState* l, string file, LuaValue v) {
enforce(v.isTable || v.isText, "Expected parameter 2 to be a table or a string.");
if(v.isText)
append(file, v.textValue);
else
{
auto t = v.tableValue;
if(t.length == 0)
return;
t.push();
scope(exit) l.pop(1);
append(file, l.get!(ubyte[])(-1));
}
},
"chdir", chdir!string,
"copy", (string from, string to) => copy(from, to),
"dirEntries", (string path, string mode) => dirEntries(path, mode.to!SpanMode).map!(de => de.name).array,
"dirEntriesGlob", (string path, string pattern, string mode)
=> dirEntries(path, pattern, mode.to!SpanMode).map!(de => de.name).array,
"exists", exists!string,
"getSize", getSize!string,
"isDir", isDir!string,
"isFile", isFile!string,
"mkdir", mkdir!string,
"mkdirRecurse", mkdirRecurse,
"readString", (string file) => readText(file),
"readBytes", (string str) => cast(ubyte[])read(str),
"remove", std.file.remove!string,
"rename", rename!(string, string),
"rmdir", rmdir!string,
"rmDirRecurse", rmdirRecurse,
"tempDir", tempDir,
"write", (LuaState* l, string file, LuaValue v) {
enforce(v.isTable || v.isText, "Expected parameter 2 to be a table or a string.");
if(v.isText)
write(file, v.textValue);
else
{
auto t = v.tableValue;
if(t.length == 0)
return;
t.push();
scope(exit) l.pop(1);
write(file, l.get!(ubyte[])(-1));
}
},
)("sh.fs");
}
Basic Functions
While Lumars provides a nice, user-friendly way to interface D and Lua functions together; sometimes you need to write a function that needs to manually manipulate the Lua stack in order to do its job.
These are referred to as "Basic" functions, since they don't need any of the fancy wrapper logic given by default.
To create a basic function, simply annotate the function with @LuaBasicFunction
:
auto lua = LuaState(null);
@LuaBasicFunction
int basic(LuaState* lua)
{
return lua.top(); // lua.top will be the amount of parameters we have. So return all params.
}
lua.register!basic("basic");
lua.doString(`
assert(basic(1) == 1)
a,b = basic(1, "2")
assert(a == 1 and b == "2")
`);
Default parameters
Lumars supports functions with default parameters. Simply... use them just like you would normally:
(Feature contribued by @Domain)
auto lua = new LuaState(null);
lua.register!(
"defaultParams", (int a, int b = 1, int c = 2) { return a+b+c; }
)("lib");
lua.doString(`
assert(lib.defaultParams(1) == 4)
assert(lib.defaultParams(1, 2) == 5)
assert(lib.defaultParams(1, 3, 5) == 9)
`);
Structs
Lumars can convert D structs to and from Lua.
When converting from Lua to D, any unknown fields are ignored, and any missing fields in the struct are set to their initial value.
In the future I'd like to introduce UDAs to customise behaviour, but for now this should be a sensible default.
static struct B
{
string a;
}
static struct C
{
string a;
}
static struct A
{
string a;
B[] b;
C[string] c;
}
auto a = A(
"bc",
[B("c")],
["c": C("123")]
);
auto l = LuaState(null);
// *Anything- that .push can use is also useable by the likes of LuaTable.
// We're doing manual stack manip just because it's simpler for this case.
l.push(a);
scope(exit) l.pop(1);
auto luaa = l.get!A(-1);
assert(luaa.a == "bc");
assert(luaa.b.length == 1);
assert(luaa.b == [B("c")]);
assert(luaa.c.length == 1);
assert(luaa.c["c"] == C("123"));
Another example:
struct Vector2D
{
float x;
float y;
}
auto l = LuaState(null);
l.doString(`
function addVectors(vectA, vectB)
return {
x = vectA.x + vectB.x,
y = vectA.y + vectB.y
}
end
`);
auto f = l.globalTable.get!LuaFunc("addVectors").bind!(Vector2D, Vector2D, Vector2D);
assert(f(
Vector2D(1, 1),
Vector2D(9, 9)
) == Vector2D(10, 10));
Executing a string or file with a different _G table
For sandboxing reasons, among other reasons, it's useful to be able to run external Lua under with a different environment table. Lumars supports this easily:
unittest
{
auto state = LuaState(null);
auto print = state._G.get!LuaFunc("print");
auto _G1 = LuaTable.makeNew(&state);
_G1["abc"] = 123;
_G1["print"] = print;
const code = "print(abc)";
state.doString(code, _G1); // or doFile
}
nogc strings
Anytime you need to access a string that's on the Lua stack, instead of specifying a string (e.g. state.get!string(-1)
) you
can instead use const(char)[]
which won't allocate any GC memory.
You do however have to keep in mind that the lifetime of the string is now attached to the lifetime of the stack variable, so be careful.
EmmyLua Annotations (IDE autocomplete)
One common annoyance when dealing with a mix of Lua and host language code, is the lack of autocompletion provided by your IDE when programming.
To help solve this issue, Lumars can help you generate a Lua file filled with EmmyLua annotations, allowing you to gain intelisense for any plugin that supports EmmyLua annotations.
It does a pretty ok job, but there's still a lot of room for improvement.
The easiest way to use it is like this:
import lumars;
import std.meta : AliasSeq;
struct S
{
int a;
LuaValue b;
}
alias EXPORT = AliasSeq!(
"myfunc1", (string s, LuaValue v) { return S.init; }
);
void registerFuncs(LuaState* lua)
{
lua.register!EXPORT("mylib");
EmmyLuaBuilder b;
b.addFunctions!EXPORT("mylib");
import std.file : write;
write("api.lua", b.toString());
/++
mylib = mylib or {}
---@class S
---@field public a number
---@field public b any
local S
--@type fun(_:string, _:any):S
mylib.myfunc1 = mylib.myfunc1 or function() assert(false, 'not implemented') end
++/
}
Then simply require("api.lua")
in your lua code, et voila (hopefully).
Nullable Support
Lumars natively supports Phobos' Nullable
type.
If the Nullable
is null: A Lua nil
is used.
If the Nullable
isn't null: The underlying value is used.
Most of the code should transparently support Nullable
.
Tuple Support
Lumars natively supports Phobos' Tuple
type.
You can use this to easily return multiple values from a function in D.
You can also use this to easily parse multiple Lua values into a single D value.
Currently Nullable
isn't supported within tuples very well.
Currently partial parsing (i.e. the tuple expects 2 values but only 1 is available) of tuples isn't supported, and will generate an exception, outside of the special case described below.
Tuple Parsing behaviour
Normally Lumars will try to parse the top n
(where n
is the number of values in the tuple) values from the stack into the tuple, and if that fails either due to type mismatches, incorrect number of values, etc. then an exception is generated.
If:
Lumars fails to parse
n
values from the top of the stack into a TupleAnd the failure occurs for the 0th value
And the 0th value is a table
And the tuple has named fields (e.g.
Tuple!(int, "foo", int, "bar")
)Then Lumars will attempt to parse the 0th value into the tuple as if it were a struct.
import std.typecons : Tuple;
Tuple!(int, string, bool) multiReturn()
{
return typeof(return)(20, "40", true);
}
auto lua = new LuaState(null);
lua.register!multiReturn("multiReturn");
lua.doString(`
local i, s, b = multiReturn()
assert(i == 20)
assert(s == "40")
assert(b)
`);
alias Employee = Tuple!(int, "ID", string, "Name", bool, "FullTime");
lua.doString(`
function employee1()
return 15305, "Domain", true
end
function employee2()
return { ID = 15605, Name = "Range", FullTime = false }
end
`);
auto f = lua.globalTable.get!LuaFunc("employee1").bind!(Employee);
auto g = lua.globalTable.get!LuaFunc("employee2").bind!(Employee);
auto employee1 = f();
auto employee2 = g();
assert(employee1.ID == 15305);
assert(employee1.Name == "Domain");
assert(employee1.FullTime);
assert(employee2.ID == 15605);
assert(employee2.Name == "Range");
assert(!employee2.FullTime);
Projects
- Inochi Session: A tool used to do live streaming with Inochi2D puppets, uses Lumars for plugins and expression bindings.
Contributing
I'm perfectly fine with anyone wanting to contribute.
I'd especially love it if you open an issue if you come across any bugs.
I'd also love it if you ever think "how do I do X?" and open an issue for it so I can add it to this README.
- 1.13.0-alpha.1 released a year ago
- BradleyChatha/lumars
- MIT
- Copyright © 2023, Bradley Chatha
- Authors:
- Dependencies:
- bindbc-lua, taggedalgebraic
- Versions:
-
1.13.0-alpha.1 2023-Aug-09 1.12.1 2023-Jun-23 1.12.0 2023-May-03 1.11.0 2023-Apr-05 1.10.0 2023-Feb-05 - Download Stats:
-
-
16 downloads today
-
111 downloads this week
-
476 downloads this month
-
5455 downloads total
-
- Score:
- 2.9
- Short URL:
- lumars.dub.pm