Lua Cookbook

Practical, copy-paste-ready recipes for Lua code generation. For the full API of each spec type, see Building Functions & Fields, Building Types & Enums, and Files & Projects.

Lua is an end-delimited language (end instead of }). sigil-stitch handles this via close_on_transition: false in its block syntax config – you get correct if/elseif/else ... end without spurious end before else. Since Lua has no type system, you’ll mostly use CodeBlock directly and sigil_quote! rather than TypeSpec.

Function

extern crate sigil_stitch;
use sigil_stitch::prelude::*;
use sigil_stitch::lang::lua::Lua;
fn main() {
let body = sigil_quote!(Lua {
    function greet(name) {
        return "Hello, "..name
    }
}).unwrap();

let file = FileSpec::builder_with("greeter.lua", Lua::new())
    .add_code(body)
    .build()
    .unwrap();
let output = file.render(80).unwrap();
}

function greet(name)
  return "Hello, "..name
end

Module with require

Use TypeName::importable to track Lua require() imports. The module path is converted to a slash-separated path in the require() call.

extern crate sigil_stitch;
use sigil_stitch::prelude::*;
use sigil_stitch::lang::lua::Lua;
fn main() {
let json = TypeName::importable("dkjson", "json");
let inspect = TypeName::importable("inspect", "inspect");

let mut cb = CodeBlock::builder();
cb.add_statement("-- %T %T", (json, inspect));
let block = cb.build().unwrap();

let file = FileSpec::builder_with("app.lua", Lua::new())
    .add_code(block)
    .build()
    .unwrap();
let output = file.render(80).unwrap();
}

local json = require("dkjson");
local inspect = require("inspect");

-- json inspect

Control flow with sigil_quote!

sigil_quote! supports if/elseif/else, for/do, and while/do blocks. Use { and } in the macro to delimit bodies – they render as indented blocks closed by end.

extern crate sigil_stitch;
use sigil_stitch::prelude::*;
use sigil_stitch::lang::lua::Lua;
fn main() {
let block = sigil_quote!(Lua {
    if x > 0 then {
        return $S("positive")
    } elseif x < 0 then {
        return $S("negative")
    } else {
        return $S("zero")
    }
}).unwrap();

let file = FileSpec::builder_with("classify.lua", Lua::new())
    .add_code(block)
    .build()
    .unwrap();
let output = file.render(80).unwrap();
}

if x > 0 then
  return "positive"
elseif x < 0 then
  return "negative"
else
  return "zero"
end

Table constructor with sigil_quote!

Braces after = or in assignments are recognized as table constructors (not control flow). No end is emitted – the braces render as literal {...}.

extern crate sigil_stitch;
use sigil_stitch::prelude::*;
use sigil_stitch::lang::lua::Lua;
fn main() {
let block = sigil_quote!(Lua {
    local user = {
        name = $S("Bob"),
        age = 42,
    }
    print(user.name)
}).unwrap();

let file = FileSpec::builder_with("user.lua", Lua::new())
    .add_code(block)
    .build()
    .unwrap();
let output = file.render(80).unwrap();
}

local user = {name = "Bob", age = 42,}
print(user.name)