luaparser 4.1.0

Installation:

The package can be installed through pip:

$ python3.6 -m pip install luaparser

It will install the shell command ‘luaparser’.

Compatibility with Lua grammar

3.2.1 => Lua 5.3 grammar 3.2.1+ => Lua 5.4 grammar

Options

These are the command-line flags:

Usage: luaparser [options] filename

CLI Options:
  --version                     Show program's version number and exit
  -h, --help                    Show this help message and exit
  -s, --source                  Source passed in a string
  -x, --xml                     Set output format to xml
  -o, --output                  Write output to file

Node structure

Each node contains the following data:

class Node:
        """Base class for AST node."""
        comments: Comments
        first_token: Optional[Token]
        last_token: Optional[Token]
        start_char: Optional[int]
        stop_char: Optional[int]
        line: Optional[int]

Working on AST tree

Minimal exemple:

from luaparser import ast

src = """
    local function sayHello()
      print('hello world !')
    end
    sayHello()
    """

tree = ast.parse(src)
print(ast.to_pretty_str(tree))

will display:

Chunk: {} 1 key
  body: {} 1 key
    Block: {} 1 key
      body: [] 2 items
        0: {} 1 key
          LocalFunction: {} 3 keys
            name: {} 1 key
              Name: {} 1 key
                id: "sayHello"
            args: [] 0 item
            body: [] 1 item
              0: {} 1 key
                Call: {} 2 keys
                  func: {} 1 key
                    Name: {} 1 key
                      id: "print"
                  args: [] 1 item
                    0: {} 1 key
                      String: {} 1 key
                        s: "hello world !"
        1: {} 1 key
          Call: {} 2 keys
            func: {} 1 key
              Name: {} 1 key
                id: "sayHello"
            args: [] 0 item

You can run through the list of all the nodes in the tree using ast.walk(tree):

from luaparser import ast
from luaparser import astnodes

tree = ast.parse("local foo = 'bar'")

for node in ast.walk(tree):
    if isinstance(node, astnodes.Name):
        process(node)

Alternatively, you can use a node visitor:

from luaparser import ast
from luaparser import astnodes

src = "local a = 42"

class NumberVisitor(ast.ASTVisitor):
    def visit_Number(self, node):
        print('Number value = ' + str(node.n))

tree = ast.parse(src)
NumberVisitor().visit(tree)

Rendering lua code

exp = Chunk(Block([
    Forin(
        targets=[Name('k'), Name('v')],
        iter=[
            Invoke(
                source=Name('bar'),
                func=Name('foo'),
                args=[Number(42)]
            )
        ],
        body=Block([
            Call(func=Name('print'), args=[Name('k'), Name('v')])
        ]),

    )
]))

print(ast.to_lua_source(exp))

Will render:

for k, v in bar:foo(42) do
    print(k, v)
end