Plua

A WIP Lua preprocessor, inspired by Nelua's preprocessor.

Features

• Metaprogramming
  • Compile time Lua
  • Interpolation
  • Metacode includes
  • Emit compiler warnings and errors
• Environment globals
• CLI
• Rust crate (API not stable)
• Lua LS plugin
• Editor syntax highlighting
  • Vim/Neovim
  • VS Code

Syntax and semantics are not yet stable, and may change.

Usage

$ plua --help
Lua preprocessor

Usage: plua [OPTIONS] <SOURCE>

Arguments:
  <SOURCE>  Source plua file

Options:
  -o, --output <OUTPUT>  Output directory. If omitted, the source directory will be used
  -e, --env <ENV>        Pass an environment global in the format name=value
  -q, --quiet            Supress stdout logging
  -d, --debug            Enable debug mode. Metaprograms will be written as a .meta.lua file
  -h, --help             Print help
  -V, --version          Print version

Example

Plua code:

##!include "lib"

local function log(msg)
    ##if debug then
        print(msg)
    ##end
end

##[[
function pow(n, e)
  return n ^ e
end
]]

log(#[pow(2, 4)]#)

local hello = "world"
print(#["hello"]#)
print(#|"hello"|#)

##function pfunc(name, fn)
    local function #|name|#()
        return pcall(#|fn|#)
    end
##end

##pfunc("throw_error", #{function()
    error("Throwing!")
end}#)

print(throw_error())

##[[
function create_logger(prefix)
    return #{
        function(msg)
            log("[#|prefix|#]: " .. msg)
        end
    }#
end
]]

local plua_log = #|create_logger("Plua")|#

plua_log(":)")

##[[
Plua.warn("Compiler warning")
-- Plua.error("Compiler error")
]]

Command:

$ plua examples/syntax.plua examples/syntax.lua 
WARN  [plua] Warning on line 104: Compiler warning
INFO  [plua] Wrote lua build\syntax.lua

Resulting Lua code:

print("Hello from plua include!")

local function log(msg)
	print(msg)
end

log(16.0)

local hello = "world"
print("hello")
print(hello)

local function throw_error()
	return pcall(function()
		error("Throwing!")
	end)
end

print(throw_error())

local plua_log = function(msg)
	log("[Plua]: " .. msg)
end

plua_log(":)")

See the examples folder for more.