py-lua-parser
A Lua parser and AST builder written in Python.
It's both a development library and a command line tool.
Installation:
The package can be installed through pip:
$ python3.6 -m pip install luaparser
It will install the shell command 'luaparser'.
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
Quickstart
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
Warning
Experimental feature
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)
endCommand line
Given:
local function log(msg)
print(msg)
end
log("hello world !")$ luaparser source.luaWill output:
{
"Chunk": {
"body": {
"Block": {
"body": [
{
"LocalFunction": {
"name": {
"Name": {
"id": "log"
}
},
"args": [
{
"Name": {
"id": "msg"
}
}
],
"body": {
"Block": {
"body": [
{
"Call": {
"func": {
"Name": {
"id": "print"
}
},
"args": [
{
"Name": {
"id": "msg"
}
}
]
}
}
]
}
}
}
},
{
"Call": {
"func": {
"Name": {
"id": "log"
}
},
"args": [
{
"String": {
"s": "hello world !"
}
}
]
}
}
]
}
}
}
}Command line
Documentation can be built with Sphinx:
$ cd doc $ pip install -r requirements.txt $ make html
