A Lua parser written in JavaScript, originally written by Oskar Schöldström for his bachelor's thesis at Arcada.
Install through npm install luaparse.
CommonJS
var parser = require('luaparse');
var ast = parser.parse('i = 0');
console.log(JSON.stringify(ast));AMD
require(['luaparse'], function(parser) {
var ast = parser.parse('i = 0');
console.log(JSON.stringify(ast));
});Browser
<script src="luaparse.js"></script>
<script>
var ast = luaparse.parse('i = 0');
console.log(JSON.stringify(ast));
</script>Basic usage:
luaparse.parse(code, options);The output of the parser is an Abstract Syntax Tree (AST) formatted in JSON.
The available options are:
wait: falseExplicitly tell the parser when the input ends.comments: trueStore comments as an array in the chunk object.scope: falseTrack identifier scopes.locations: falseStore location information on each syntax node.ranges: falseStore the start and end character locations on each syntax node.onCreateNode: nullA callback which will be invoked when a syntax node has been completed. The node which has been created will be passed as the only parameter.onCreateScope: nullA callback which will be invoked when a new scope is created.onDestroyScope: nullA callback which will be invoked when the current scope is destroyed.onLocalDeclaration: nullA callback which will be invoked when a local variable is declared. The identifier will be passed as the only parameter.luaVersion: '5.1'The version of Lua the parser will target; supported values are'5.1','5.2','5.3'and'LuaJIT'.extendedIdentifiers: falseWhether to allow code points ≥ U+0080 in identifiers, like LuaJIT does. Note: settingluaVersion: 'LuaJIT'currently does not enable this option; this may change in the future.encodingMode: 'none'Defines the relation between code points ≥ U+0080 appearing in parser input and raw bytes in source code, and how Lua escape sequences in JavaScript strings should be interpreted. See the Encoding modes section below for more information.
The default options are also exposed through luaparse.defaultOptions where
they can be overriden globally.
There is a second interface which might be preferable when using the wait
option.
var parser = luaparse.parse({ wait: true });
parser.write('foo = "');
parser.write('bar');
var ast = parser.end('"');This would be identical to:
var ast = luaparse.parse('foo = "bar"');If the following code is executed:
luaparse.parse('foo = "bar"');then the returned value will be:
{
"type": "Chunk",
"body": [
{
"type": "AssignmentStatement",
"variables": [
{
"type": "Identifier",
"name": "foo"
}
],
"init": [
{
"type": "StringLiteral",
"value": "bar",
"raw": "\"bar\""
}
]
}
],
"comments": []
}Unlike strings in JavaScript, Lua strings are not Unicode strings, but bytestrings (sequences of 8-bit values); likewise, implementations of Lua parse the source code as a sequence of octets. However, the input to this parser is a JavaScript string, i.e. a sequence of 16-bit code units (not necessarily well-formed UTF-16). This poses a problem of how those code units should be interpreted, particularly if they are outside the Basic Latin block ('ASCII').
The encodingMode option specifies how these issues should be handled.
Possible values are as follows:
'none': Source code characters all pass through as-is and string literals are not interpreted at all; the string literal nodes contain the valuenull. This is the default mode.'x-user-defined': Source code has been decoded with the WHATWGx-user-definedencoding; escapes of bytes in the range [0x80, 0xff] are mapped to the Unicode range [U+F780, U+F7FF].'pseudo-latin1': Source code has been decoded with the IANAiso-8859-1encoding; escapes of bytes in the range [0x80, 0xff] are mapped to Unicode range [U+0080, U+00FF]. Note that this is not the same as how WHATWG standards define theiso-8859-1encoding, which is to say, as a synonym ofwindows-1252.
The default AST structure is somewhat inspired by the Mozilla Parser API but can easily be overriden to customize the structure or to inject custom logic.
luaparse.ast is an object containing all functions used to create the AST, if
you for example wanted to trigger an event on node creations you could use the
following:
var luaparse = require('luaparse'),
events = new (require('events').EventEmitter);
Object.keys(luaparse.ast).forEach(function(type) {
var original = luaparse.ast[type];
luaparse.ast[type] = function() {
var node = original.apply(null, arguments);
events.emit(node.type, node);
return node;
};
});
events.on('Identifier', function(node) { console.log(node); });
luaparse.parse('i = "foo"');this is only an example to illustrate what is possible and this particular
example might not suit your needs as the end location of the node has not been
determined yet. If you desire events you should use the onCreateNode callback
instead).
The lexer used by luaparse can be used independently of the recursive descent
parser. The lex function is exposed as luaparse.lex() and it will return the
next token up until EOF is reached.
Each token consists of:
typeexpressed as an enum flag which can be matched withluaparse.tokenTypes.valueline,lineStartrangecan be used to slice out raw values, eg.foo = "bar"will return aStringLiteraltoken with the valuebar. Slicing out the range on the other hand will return"bar".
var parser = luaparse.parse('foo = "bar"', { wait: true });
parser.lex(); // { type: 8, value: "foo", line: 1, lineStart: 0, range: [0, 3] }
parser.lex(); // { type: 32, value: "=", line: 1, lineStart: 0, range: [4, 5]}
parser.lex(); // { type: 2, value: "bar", line: 1, lineStart: 0, range: [6, 11] }
parser.lex(); // { type: 1, value: "<eof>", line: 1, lineStart: 0, range: [11 11] }
parser.lex(); // { type: 1, value: "<eof>", line: 1, lineStart: 0, range: [11 11] }Have a look in the examples directory of the repository for some code examples or check them out live.
The luaparse executable can be used in your shell by installing luaparse globally using npm:
$ npm install -g luaparse
$ luaparse --help
Usage: luaparse [option]... [file|code]...
Options:
-c|--code [code] parse code snippet
-f|--file [file] parse from file
-b|--beautify output an indenteted AST
--[no]-comments store comments. defaults to true
--[no]-scope store variable scope. defaults to false
--[no]-locations store location data on syntax nodes. defaults to false
--[no]-ranges store start and end character locations. defaults to false
-q|--quiet suppress output
-h|--help
-v|--version
--verbose
Examples:
luaparse --no-comments -c "locale foo = \"bar\""
luaparse foo.lua bar.luaExample usage
$ luaparse "i = 0"
{"type":"Chunk","body":[{"type":"AssignmentStatement","variables":[{"type":"Identifier","name":"i"}],"init":[{"type":"NumericLiteral","value":0,"raw":"0"}]}],"comments":[]}Has been tested in at least IE6+, Firefox 3+, Safari 4+, Chrome 10+, Opera 10+, Node 0.4.0+, RingoJS 0.8-0.9, Rhino 1.7R4-1.7R5, Nashorn 1.8.0.
TL;DR simply run make qa. This will run all quality assurance scripts but
assumes you have it set up correctly.
Begin by cloning the repository and installing the development dependencies
with npm install.
The luaparse test suite uses testem as a test runner, and because of this it's very easy to run the tests using different javascript engines or even on locally installed browsers.
make testuses node.make testem-enginesuses node, ringo and rhino 1.7R5. This requires that you have the engines installed.make test-nodeuses a custom command line reporter to make the output easier on the eyes while practicing TDD.- By installing
testemglobally you can also run the tests in a locally installed browser.
- You can check the function complexity using complexity-report
using
make complexity-analysis - Running
make coveragewill generate the coverage report. To simply check that all code has coverage you can runmake coverage-analysis. make lint,make benchmark,make profile.
By running make docs all documentation
will be generated.
- Initial tests are scaffolded from yueliang and then manually checked for error.
- Much of the code is based on LuaMinify, the Lua source and Esprima. All awesome projects.
MIT
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