How do I read the name of a File or a Directory?
There is a property 'path' but that returns the entire file path.
Would be nice to have a property like 'name' that just returns the last part of the path.
In Java there is a method called File.name();
You can use the path package to do that :
import 'package:path/path.dart' as path;
main() {
path.basename('path/to/foo.dart'); // -> 'foo.dart'
path.basename('path/to'); // -> 'to'
}
See the path package documentation for more explanations.
Since Dart Version 2.6 has been announced and it's available for flutter version 1.12 and higher, You can use extension methods. It will provide a more readable and global solution to this problem.
file_extensions.dart :
import 'dart:io';
extension FileExtention on FileSystemEntity{
String get name {
return this?.path?.split("/")?.last;
}
}
and name getter is added to all the file objects. You can simply just call name on any file.
main() {
File file = new File("/dev/dart/work/hello/app.dart");
print(file.name);
}
Read the document for more information.
Note:
Since extension is a new feature, it's not fully integrated into IDEs yet and it may not be recognized automatically. You have to import your extension manually wherever you need that. Just make sure the extension file is imported:
import 'package:<your_extention_path>/file_extentions.dart';
Related
I develop a flutter app, define serveral models in 'model' package.
Then I declare a class Example in 'model' for example.
model/example.dart
class Example {
#override
String toString() {
return 'class example';
}
}
test_a.dart
import 'package:example/model/example.dart'
Example testA() {
return Example()
}
test.dart
import 'model/example.dart'
import 'test_a.dart'
test() {
Example example = testA();
if (example is Example) {
print('this class is Example');
} else {
print('$example');
}
}
I will get output class example🌚
If I change from import 'model/example.dart' to import 'package:example/model/example.dart' in test.dart, then I will get the output this class is Example.
So I'm confused what is different between the full path and relative path in dart.
package imports
'package:... imports work from everywhere to import files from lib/*.
relative imports
Relative imports are always relative to the importing file.
If lib/model/test.dart imports 'example.dart', it imports lib/model/example.dart.
If you want to import test/model_tests/fixture.dart from any file within test/*, you can only use relative imports because package imports always assume lib/.
This also applies for all other non-lib/ top-level directories like drive_test/, example/, tool/, ...
lib/main.dart
There is currently a known issue with entry-point files in lib/* like lib/main.dart in Flutter. https://github.com/dart-lang/sdk/issues/33076
Dart always assumed entry-point files to be in other top-level directories then lib/ (like bin/, web/, tool/, example/, ...).
Flutter broke this assumption.
Therefore you currently must not use relative imports in entry-point files inside lib/
See also
How to reference another file in Dart?
I'm trying to extract c++ source code's info.
One is field's type.
when source code like under I want to extract info's Type when info.call() is called.
Info info;
//skip
info.call(); //<- from here
Trough making a visitor which visit IASTName node, I tried to extract type info like under.
public class CDTVisitor extends ASTVisitor {
public CDTVisitor(boolean visitNodes) {
super(true);
}
public int visit(IASTName node){
if(node.resolveBinding().getName().toString().equals("info"))
System.out.println(((IField)node.getBinding()).getType());
// this not work properly.
//result is "org.eclipse.cdt.internal.core.dom.parser.ProblemType#86be70a"
return 3;
}
}
Assuming the code is in fact valid, a variable's type resolving to a ProblemType is an indication of a configuration problem in whatever tool or plugin is running this code, or in the project/workspace containing the code on which it is run.
In this case, the type of the variable info is Info, which is presumably a class or structure type, or a typedef. To resolve it correctly, CDT needs to be able to see the declaration of this type.
If this type is not declared in the same file that's being analyzed, but rather in a header file included by that file, CDT needs to use the project's index to find the declaration. That means:
The AST must be index-based. For example, if using ITranslationUnit.getAST to create the AST, the overload that takes an IIndex parameter must be used, and a non-null argument must be provided for it.
Since an IIndex is associated with a CDT project, the code being analyzed needs to be part of a CDT project, and the project needs to be indexed.
In order for the indexer to resolve #include directives correctly, the project's include paths need to be configured correctly, so that the indexer can actually find the right header files to parse.
Any one of these not being the case can lead to a type resolving to a ProblemType.
Self response.
The reason I couldn't get a binding object was the type of AST.
When try to parse C++ source code, I should have used ICPPASTTranslationUnit.
There is no code related this, I used IASTTranslationUnit as a return type of AST.
After using ICPPASTTranslationUnit instead of IASTTranslationUnit, I solved this problem.
Yes, I figure it out! Here is the entire code which can index all files in "src" folder of a cpp project and output the resolved type binding for all code expressions including the return value of low level API such as memcpy. Note that the project variable in following code is created by programatically importing an existing manually configured cpp project. I often manually create an empty cpp project and programatically import it as a general project (once imported, Eclipse will automatically detect the project type and complete the relevant configuration of CPP project). This is much more convenient than creating and configuring a cpp project from scratch programmatically. When importing project, you'd better not to copy the project or containment structures into workspace, because this may lead to infinitely copying same project in subfolder (infinite folder depth). The code works in Eclipse-2021-12 version. I download Eclipse-For-cpp and install plugin-development and jdt plugins. Then I create an Eclipse plugin project and extend the "org.eclipse.core.runtime.applications" extension point.
In another word, it is an Eclipse-Application plugin project which can use nearly all features of Eclipse but do not start the graphical interface (UI) of Eclipse. You should add all cdt related non-ui plugins as the dependencies because new version of Eclipse does not automatically add missing plugins any more.
ICProject cproject = CoreModel.getDefault().getCModel().getCProject(project.getName());
// this code creates index for entire project.
IIndex index = CCorePlugin.getIndexManager().getIndex(cproject);
IFolder folder = project.getFolder("src");
IResource[] rcs = folder.members();
// iterate all source files in src folder and visit all expressions to print the resolved type binding.
for (IResource rc : rcs) {
if (rc instanceof IFile) {
IFile f = (IFile) rc;
ITranslationUnit tu= (ITranslationUnit) CoreModel.getDefault().create(f);
index.acquireReadLock(); // we need a read-lock on the index
ICPPASTTranslationUnit ast = null;
try {
ast = (ICPPASTTranslationUnit) tu.getAST(index, ITranslationUnit.AST_SKIP_INDEXED_HEADERS);
} finally {
index.releaseReadLock();
}
if (ast != null) {
ast.accept(new ASTVisitor() {
#Override
public int visit(IASTExpression expression) {
// get the resolved type binding of expression.
IType etp = expression.getExpressionType();
System.out.println("IASTExpression type:" + etp + "#expr_str:" + expression.toString());
return super.visit(expression);
}
});
}
}
}
Suppose I have this:
benchmark.dart:
library benchmark;
benchmark() {...}
app.dart:
import 'benchmark.dart'; // functions from this lib are now accessible in this file
export 'benchmark.dart'; // does this make them accessible in all files imported below?
import 'model.dart';
void main() {
doSomething();
}
model.dart
doSomething() {
benchmark(); // => Error, no such method, unless
// I import 'benchmark.dart' above in this file!
}
Is this the right behavior? How do I make benchmark accessible without importing the lib in model.dart?
You have to make the imports in every library you want to use other libraries.
What you might do is to join several files to one library using part 'model.dart'; (parent file) and part of app; (linked file).
Then the types and functions imported in the parent file are available in all files of this library.
I want to know what the current directory is. I don't want to shell out to run pwd. Is there an easy way to do this in Dart?
Indeed there is!
import 'dart:io';
main() {
Directory current = Directory.current;
}
Note: this only works on the command-line, not in the browser.
Read more about the API docs for Directory.current.
Directory.current.path does it if you want a string, Directory.current for a Directory.
(note: Directory is defined in dart:io)
I know you can use the library, import and even #import, but which is correct?
I have got two files, MainClass.dart and Library.Dart, and I want to add a reference to Library.dart in MainClass.dart. How can I do that?
Firstly let me just preface this by saying please do not use the hash symbol before import or library or anything else. This is an old syntax that is being deprecated. So we no longer want to use #import('...') The correct syntax is:
import 'some_file.dart';
That said, there are two different things we can do to access different dart source files within our current file. The first is to import the file. We use this such as in your case when you want to bring a different library into the current file (or more accurately current library).
Usually if your files are in the same directory, or a sub directory of the current one we would import them like this:
import 'lib/library.dart';
However If you are using the pub package layout you can also use some special short-cut references as well to import files (particularly from other packages you've imported). I highly suggest reading the documents on the pub site, as most applications and libraries are designed with this in mind. It also has suggestions on best naming conventions such as filenames in all lower case, and using underscore for spaces, and directory layouts.
The other important thing to know about bringing a dart file into another file, is that we can use the part and part of directives. This used to be called #source but was changed (with the removal of the hash sign) to reduce confusion. The part directive is used when we want to write a single library which spans multiple files. Say for instance you have an Awesome Library, which is starting to get a little large for a single file. We will create the main file of the library (not to be confused with the main method). This file will usually have the same name as the library itself.
// awesome_library.dart
library awesome_library;
import 'dart:math';
import '...';
// this injects all the content of secret_file.dart
// into this file right here almost as if it was
// here in the first place.
part 'src/secret_file.dart';
// The rest of our file here
// ...
The part directive basically takes everything from our src/secret_file.dart and inserts it into that part of the file. This allows us to split our huge Awesome Library into multiple smaller files that are easier to maintain. While not specifically required, it is helpful to use the part of directive in our secret_file.dart to help the editor know that it is "part of" the library.
// secret_file.dart
part of awesome_library;
// ... Rest of our secret_file code below.
Note that when using a part file like this, the part(s) (that is everything that is not the main file of the library) cannot import or use library declarations themselves. They import whatever is imported into the the main file, but they cannot add any additional imports.
For more information about library see this link.
Importing your own created libraries:
You will be importing the filename.dart and not the name of your library.
So if the name of your library is: myLib and it is saved in the file: someDartFile.dart you will have to
import 'someDartFile.dart';
If you have on Windows a library at: K:\SomeDir\someFile.dart you will need to write:
import '/K:/SomeDir/someFile.dart';
example:
import 'LibraryFile.dart'; //importing myLib
void main(){
//a class from myLib in the LibraryFile.dart file
var some = new SomeClassFromMyLibrary();
}
myLib in LibraryFile.dart:
library myLibrary;
import 'dart:math';
class SomeClassFromMyLibrary{
String _str = "this is some private String only to myLibrary";
String pubStr = "created instances of this class can access";
}
Here a full example.
//TestLib.dart
import 'LibFile.dart'; //SomeLibrary
void main() {
print("Hello, World!");
LibFile l = new LibFile();
print(l.publicString);//public
print(l.getPrivateString);//private
print(l.getMagicNumber); //42
}
//LibFile.dart
library SomeLibrary;
part 'LibFile2.dart';
class LibFile {
String _privateString = "private";
String publicString = "public";
String get getPrivateString => _privateString;
int get getMagicNumber => new LibFile2().number;
}
//LibFile2.dart
part of SomeLibrary;
class LibFile2 {
int number = 42;
}
Although i am answering very late, but the answer may help new developer.
Always use pubspec.yaml file in your dart package(application/library).
once you run pub get command it will add your local library in the dependencies list in .packages file.
Consider i have following project structure.
To refer to the content of greeting.dart in my main.dart file i should add the library as below
import 'package:my_project_name/greeting.dart'
Once imported we can use the content of greeting.dart file in our main.dart file.
Note: we have not used the actual path as you can see 'lib' directory is missing.
First make sure that's the name which you have mentioned in pubspec.yaml and the file you want to import are sharing the exact same name
example:
pubspec.yaml
name: flutter_wordpress_app
description: flutter wordpress app
...
....
// dirOne/dirTwo/greeting.dart
class FavArticleBloc {
// Your code goes here
}
import 'package:flutter_wordpress_app/dirOne/dirTwo/greeting.dart'
void main(){
var some = new FavArticleBloc();
}
But
in the main.dartyou don't need to specify
import 'package:flutter_wordpress_app
just do like below
import 'dirOne/dirTwo/greeting.dart