Is it possible to run transformer on a command line application before running it?
For example, if I have a class that mixes in Observable class. And I would like to transform it so that dirtCheck is transformed into ChangeNotifier.
holder.dart
class Member extends Object with ChangeNotifier {
#observable
String name = "";
}
class Holder extends Object with ChangeNotifier {
Holder() {
}
#observable
Member member = new Member();
}
pubspec.yml
transformers:
- observe:
files:
- bin/models/holder.dart
If I run this application from IntelliJ IDE, it doesn't seem to run the transformer on it before executing main.dart.
Thanks.
Transfomers are not applied to command line apps. Only code that is served using pub serve or pub build runs and applies transformers. Your code should run on the server/command line as is. There is no need to run transformers.
Transformers are used for observe to replace dart:mirrors access by generated code to prevent code bloat for dart2js-generated JS but this is no issue on the command line.
Related
I'm writing a discord bot using the nyxx library and want use dynamic file import for load command info and handler. But, after 5 hours of searching with Google, I didn't find anything to help me do that.
In Node.js, I can use require() or import() for it: Does the dart have something like that?
A small code snippet, showing what I want do:
this.commands = new Collection();
fs.readdirSync('./src/commands').filter(( f ) => f.endsWith( '.js' )).forEach((file) => {
const command = require(`../commands/${file}`);
this.commands.set( command.info.name, command );
});
Is it possible to do this or not? (I don't like to write many imports for commands and register it in lib.)
You can in theory use Isolate.spawnUri to spawn external Dart programs to run in its own Isolate instances that can then communicate back to the main program using SendPort.
It does, however, come with some limitations. E.g. it is very limited what types of objects you can send though SendPort when using spawnUri since the two programs does not share any type information (compared to Isolate.spawn which does allow you to send your own custom types). The documented types you can send can be found here:
Null
bool
int
double
String
List or Map (whose elements are any of these)
TransferableTypedData
SendPort
Capability
https://api.dart.dev/stable/2.17.6/dart-isolate/SendPort/send.html
But it does allow us to make some kind of protocol and you can create some helper class around this to handle the conversion of a known object structure into e.g. Map<String, Object>.
A small example that works with Dart VM would be:
Your command implemented as: command.dart
import 'dart:isolate';
void main(List<String> arguments, Map<String, Object> message) {
final userName = message['username'] as String;
final sendPort = message['port'] as SendPort;
sendPort.send('Hi $userName. '
'You got a message from my external command program!');
}
Your server that calls your command: server.dart
import 'dart:isolate';
void main() {
final recievePort = ReceivePort();
recievePort.listen((message) {
print('Got the following message: $message');
recievePort.close();
});
Isolate.spawnUri(Uri.file('command.dart'), [], {
'username': 'julemand101',
'port': recievePort.sendPort,
});
}
If running this with: dart server.dart you, hopefully, get:
Got the following message: Hi julemand101. You got a message from my external command program!
If you want to compile your application, you can do so by doing the following. You need to compile the command.dart, since a compiled Dart program does not understand how to read Dart code.
dart compile exe server.dart
dart compile aot-snapshot command.dart
You should here change Uri.file('command.dart') to Uri.file('command.aot') since the file-extension for aot-snapshot are .aot.
If everything works, you should be able to see:
> .\server.exe
Got the following message: Hi julemand101. You got a message from my external command program!
I am working on a dart package with includes over 200 models and at the moment i have to write manually one line of "export" for each model, to make the models available for everyone who uses this package.
I want the build runner to generate one dart file which contains every export definition.
Therefore I would create an annotation "ExportModel". The builder should search for each class annotated with this annotation.
I tried creating some Builders, but they will generate a *.g.dart file for each class that is annotated. I just want to have one file.
Is where a way to create a builder that runs only once and creates a file at the end ?
The short answer to your question of a builder that only runs once and creates a single file in the package is to use r'$lib$' as the input extension. The long answer is that to find the classes that are annotated you probably want an intermediate output to track them.
I'd write this with 2 builders, one to search for the ExportModel annotation, and another to write the exports file. Here is a rough sketch with details omitted - I haven't tested any of the code here but it should get you started on the right path.
Builder 1 - find the classes annotated with #ExportModel().
Could write with some utilities from package:source_gen, but can't use LibraryBuilder since it's not outputting Dart code...
Goal is to write a .exports file next to each .dart file which as the name of all the classes that are annotated with #ExportModel().
class ExportLocatingBuilder implements Builder {
#override
final buildExtensions = const {
'.dart': ['.exports']
};
#override
Future<void> build(BuildStep buildStep) async {
final resolver = buildStep.resolver;
if (!await resolver.isLibrary(buildStep.inputId)) return;
final lib = LibraryReader(await buildStep.inputLibrary);
final exportAnnotation = TypeChecker.fromRuntime(ExportModel);
final annotated = [
for (var member in lib.annotatedWith(exportAnnotation)) element.name,
];
if (annotated.isNotEmpty) {
buildStep.writeAsString(
buildStep.inputId.changeExtension('.exports'), annotated.join(','));
}
}
}
This builder should be build_to: cache and you may want to have a PostProcessBuilder that cleans up all the outputs it produces which would be specified with applies_builder. You can use the FileDeletingBuilder to cheaply implement the cleanup. See the FAQ on temporary outputs and the angular cleanup for example.
Builder 2 - find the .exports files and generate a Dart file
Use findAssets to track down all those .exports files, and write an export statement for each one. Use a show with the content of the file which should contain the names of the members that were annotated.
class ExportsBuilder implements Builder {
#override
final buildExtensions = const {
r'$lib$': ['exports.dart']
};
#override
Future<void> build(BuildStep buildStep) async {
final exports = buildStep.findAssets(Glob('**/*.exports'));
final content = [
await for (var exportLibrary in exports)
'export \'${exportLibrary.changeExtension('.dart').uri}\' '
'show ${await buildStep.readAsString(exportLibrary)};',
];
if (content.isNotEmpty) {
buildStep.writeAsString(
AssetId(buildStep.inputId.package, 'lib/exports.dart'),
content.join('\n'));
}
}
}
This builder should likely be build_to: source if you want to publish this file on pub. It should have a required_inputs: [".exports"] to ensure it runs after the previous builder.
Why does it need to be this complex?
You could implement this as a single builder which uses findAssets to find all the Dart files. The downside is that rebuilds would be much slower because it would be invalidated by any content change in any Dart file and you'd end up parsing all Dart code for a change in any Dart code. With the 2 builder approach then only the individual .exports which come from a changed Dart file need to be resolved and rebuilt on a change, and then only if the exports change will the exports.dart file be invalidated.
Older versions of build_runner also didn't support using the Resolver to resolve code that isn't transitively imported from the input library. Recent version of build_runner have relaxed this constraint.
I created a bare-bones datagrid using web-ui for testing and had it working just fine. Then I decided to try to declare it as a component. I changed around the library references and now it is giving me the above error when I try to run the application. You can see my file structure below. The reason I am getting the "ambiguous reference" message when I try to run it is that when I went into the auto-generated DataGrid.dart file in the out directory, it had the following declaration
import 'DataGrid.dart';
...
import '../DataGrid.dart';
I am confused as to why the generated code imports them both. One thing that I considered is that it could be because the DataGridPage.html file instantiates my DataGrid component and my DataGridPage.dart file imports DataGrid.dart so that it can have references to DataGridColumn (it needs to set the columns for the DataGrid). In DataGridPage.dart, I also attach to certain DataGrid events such as SortColumnChanged and SelectionChanged so I need to request a copy of my DataGrid instance in DataGridPage.dart (I don't think there is a way to attach to events from the web component instantiation in DataGridPage.html).
Any ideas about what I am doing wrong?
Here is my file structure:
DataGrid.dart
--------------------------------------------
library datagrid;
...
part 'DataGridColumn.dart';
part 'DataGridRow.dart';
class DataGrid extends WebComponent{...}
DataGridRow.dart
--------------------------------------------
part of datagrid;
class DataGridRow {...}
DataGridColumn.dart
--------------------------------------------
part of datagrid;
class DataGridColumn {...}
DataGrid.html
--------------------------------------------
[contains the component declaration UI]
DataGridPage.html
-----------------------------------------
...
<div is="s-datagrid" id="myDataGrid" ItemsSource="{{app.Assets}}" Columns="{{app.Columns}}"></div>
...
DataGridPage.dart
--------------------------------------------
import 'DataGrid.dart';
import 'Asset.dart';
void main() {
}
DataGridApp _app;
DataGridApp get app {
if (_app == null) {
_app = new DataGridApp();
}
return _app;
}
class DataGridApp{
//provides ItemsSource and DataGridColumn data
}
jmesserly has answered this on the github site. He said that you need to remove the component import in your main dart file. So in my example I would remove the import 'DataGrid.dart' statement from the DataGridPage.dart. The IDE will give you a warning but you can ignore it because it will actually be run from the out folder.
GitHub Web-UI Issue 342
I'm new to dart, and trying to use dart to write a hello world and a unit test, but I get the error:
duplicate top-level declaration 'METHOD main' at ../app.dart::5:6
My project dir is test-dart, and it has 3 files.
test-dart/models.dart
class User {
hello(String name) {
print("Hello, ${name}");
}
}
test-dart/app.dart
#library("app");
#source("./models.dart");
void main() {
new User().hello("app");
}
test-dart/test/test.dart
#library("test");
#import("../app.dart");
void main() {
print("hello, test");
}
Now there is an error in "test.dart" on void main(), the error message is:
duplicate top-level declaration 'METHOD main' at ../app.dart::5:6
The two main() methods are in different libraries, why they are still duplicated? How to fix it?
If you import a library like this #import('../app.dart), then all names from app.dart become visible in the importing code (all public names, actually -- those that don't start with a _). So in your test.dart library, you now have two main functions visible. That is obviously a collision. There are two ways to solve it (that I know of).
First: import the library with a prefix, like this: #import('../app.dart', prefix: 'app'). Then, all public names from app.dart are still visible, but only with an app prefix, so the main function from app.dart is only accessible by app.main. No collision here, but you have to use a prefix everytime.
Second: using a show combinator, like this: #import('../app.dart', show: ['a', 'b']). Then, it is no longer true that all names from app.dart are visible, only those explicitly named (a and b here). I'm not sure if this is already implemented, though.
Maybe in the future, we will get something opposite to the show combinator, so that you could do #import('../app.dart', hide: ['main']). That would be the best solution for your problem, but it isn't in the current language (as specified by 0.09).
You are importing app.dart without a prefix which means that the symbols of the importing and imported library can collide if there are duplicates such as in your example.
To resolve these collisions the library import allows you to prefix imports with an identifier. Your example should work if you change test.dart as follows:
#library("test");
#import("../app.dart", prefix: "app");
void main() {
print("hello, test");
app.main();
new app.User().hello("main");
}
Notice how the classes and top-level functions in the app.dart library are now accessed using the "app" prefix and thus do not collide with the names in test.dart.
I've tried to use the new Groovy Grape capability in Groovy 1.6-beta-2 but I get an error message;
unable to resolve class com.jidesoft.swing.JideSplitButton
from the Groovy Console (/opt/groovy/groovy-1.6-beta-2/bin/groovyConsole) when running the stock example;
import com.jidesoft.swing.JideSplitButton
#Grab(group='com.jidesoft', module='jide-oss', version='[2.2.1,)')
public class TestClassAnnotation {
public static String testMethod () {
return JideSplitButton.class.name
}
}
I even tried running the grape command line tool to ensure the library is imported. Like this;
$ /opt/groovy/groovy-1.6-beta-2/bin/grape install com.jidesoft jide-oss
which does install the library just fine. How do I get the code to run/compile correctly from the groovyConsole?
There is still some kinks in working out the startup/kill switch routine. For Beta-2 do this in it's own script first:
groovy.grape.Grape.initGrape()
Another issue you will run into deals with the joys of using an unbounded upper range. Jide-oss from 2.3.0 onward has been compiling their code to Java 6 bytecodes, so you will need to either run the console in Java 6 (which is what you would want to do for Swing anyway) or set an upper limit on the ranges, like so
import com.jidesoft.swing.JideSplitButton
#Grab(group='com.jidesoft', module='jide-oss', version='[2.2.1,2.3.0)')
public class TestClassAnnotation {
public static String testMethod () {
return JideSplitButton.class.name
}
}
new TestClassAnnotation().testMethod()
I finally got it working for Groovy Shell (1.6.5, JVM: 1.6.0_13). This should be documented better.
First at the command line...
grape install org.codehaus.groovy.modules.http-builder http-builder 0.5.0-RC2
Then in groovysh...
groovy:000> import groovy.grape.Grape
groovy:000> Grape.grab(group:'org.codehaus.groovy.modules.http-builder', module:'http-builder', version:'0.5.0-RC2')
groovy:000> def http= new groovyx.net.http.HTTPBuilder('http://rovio')
===> groovyx.net.http.HTTPBuilder#91520
The #grab is better used in a file than the shell.
Ok. Seems like this a short working demo (running from the groovyConsole)
groovy.grape.Grape.initGrape()
#Grab(group='com.jidesoft', module='jide-oss', version='[2.2.1,2.3.0)')
public class UsedToExposeAnnotationToComplier {}
com.jidesoft.swing.JideSplitButton.class.name
When run it produces
Result: "com.jidesoft.swing.JideSplitButton"
Very cool!!
The import statement must appear after the grabs.
Ps. At least one import statement must exists after the grabs
#Grab(group='com.jidesoft', module='jide-oss', version='[2.2.1,)')
import com.jidesoft.swing.JideSplitButton
public class TestClassAnnotation {
public static String testMethod () {
return JideSplitButton.class.name
}
}
Different example using latest RC-2 (note: Grab annotates createEmptyInts):
// create and use a primitive array
import org.apache.commons.collections.primitives.ArrayIntList
#Grab(group='commons-primitives', module='commons-primitives', version='1.0')
def createEmptyInts() { new ArrayIntList() }
def ints = createEmptyInts()
ints.add(0, 42)
assert ints.size() == 1
assert ints.get(0) == 42
Another example (note: Grab annotates getHtml):
// find the PDF links in the Java 1.5.0 documentation
#Grab(group='org.ccil.cowan.tagsoup', module='tagsoup', version='0.9.7')
def getHtml() {
def parser = new XmlParser(new org.ccil.cowan.tagsoup.Parser())
parser.parse("http://java.sun.com/j2se/1.5.0/download-pdf.html")
}
html.body.'**'.a.#href.grep(~/.*\.pdf/).each{ println it }
Another example (note: Grab annotates getFruit):
// Google Collections example
import com.google.common.collect.HashBiMap
#Grab(group='com.google.code.google-collections', module='google-collect', version='snapshot-20080530')
def getFruit() { [grape:'purple', lemon:'yellow', orange:'orange'] as HashBiMap }
assert fruit.inverse().yellow == 'lemon'