The Rust glob crate is fairly straight forward, as long as no files are added during execution. But what happends if the state of the filesystem changes?
Consider the following situation:
// The folder contains a cute giraffe and a cute zebra.
let mut animals = glob("images/cute_*.jpg");
// A cute cat is added to the folder.
let first = animals.next();
// A cute dog is added to the folder.
let second = animals.next();
What will first and second be? A giraffe and a zebra? A cat and a dog?
To rephrase the question in more technical terms: Does glob represent a snapshot of the filesystem as it was when it is called? Or perhaps when iteration begins? Or is "live" finding recently added files?
Looking at the source code for glob, you can see that:
It doesn't really do anything until the first time you call next, so in your example it would see the cat.
It reads the whole directory at once the first time it is needed, so in your example it would not see the dog.
When your pattern matches several directories, it reads them one by one, so any files that are added to a directory before it starts processing that specific directory will be visible. Once processing of the directory has started, the list is frozen and new files will not be seen.
In your example, it would therefore return the giraffe, zebra and cat in no particular order.
Note however that this is looking at the code as it currently stands, behaviour may change if the code is modified.
Related
I would like to compare two directories, and be able to copy one file from a directory to an other ( for example, copy the file dog.png from the directory 1 to the directory 2 if this one doesn't have this file)
I know that there is the "diff" command diff -rq rep1 rep2 which include recursion, but I don't think that the result is convenient (the way it's presented) to work with it. Plus , it doesn't care about the path as long as there is the same file somewhere in the second directory.
My idea was to list the elements of the rep1 , then do a loop, and if there is an other directory, open it and do another loop, do that until there are only files and then compare and go back to the previous loop. I know that seems like recursion, I wanted to know if it was possible to make it that way ? Or if it's too complex.
Mike C: Welcome to Stack Overflow! I would try posing this Q to another site https://softwareengineering.stackexchange.com/ as it does not quite fit the "norm" for Stack Overflow where usually you ask questions about concrete code.I'm going to try to answer the Q anyways.
Yes you could solve this with recursion. You would make one function or method that takes the full path to a directory as it's input, then that function would list all sub-directories and call itself on each of them.
The fact taht you will be scanning two directories in paralelle will add some complexity, because you have to decide what to do in 3 cases:
Subdir exists only in A
Subdir exists only in B
Subdir exists in both
I would implement this by passing TWO full paths to the function, and simply change behsaviour when one of them was null.
Lets say that there is a function in my Delphi app:
MsgBox
and there is a string which has MsgBox in it.
I know what most of you are going to say is that its possible, but I think it is possible because I opened the compiled exe(compiled using delphi XE2) using a Resource Editor, and that resource editor was built for Delphi. In that, I could see most of the code I wrote, as I wrote it. So since the variables names, function names etc aren't changed during compile, there should a way to execute the functions from a string, but how? Any help will be appreciated.
EDIT:
What I want to do is to create a simple interpreter/scripting engine. And this is how its supposed to work:
There are two files, scr.txt and arg.txt
scr.txt contains:
msg_show
0
arg.txt contains:
"Message"
And now let me explain what that 0 is:
First, scr.txt's first line is function name
second line tells that at which line its arguments are in the arg.txt, i.e 0 tells that "Message" is the argument for msg_show.
I hope my question is now clear.
I want to make a simple scripting engine.
In order to execute arbitrary code stored as text, you need a compiler or an interpreter. Either you need to write one yourself, or embed one that already exists. Realistically, the latter option is your best option. There are a number available but in my view it's hard to look past dwscript.
I think I've already solved my problem! The answer is in this question's first answer.
EDIT:
But with that, as for a workaround of the problem mentioned in first comment, I have a very easy solution.
You don't need to pass all the arguments/parameters to it. Just take my example:
You have two files, as mentioned in the question. Now you need to execute the files. It is as simple as that:
read the first line of scr.txt
check if it's a function. If not, skip the line
If yes, read the next line which tells the index where it's arguments are in arg.txt
pass on the index(an integer) to the "Call" function.
Now to the function which has to be executed, it should know how many arguments it needs. i.e 2
Lets say that the function is "Sum(a,b : integer)".It needs 2 arguments
Now let the function read the two arguments from arg.txt.
And its done!
I hope it will help you all.
And I can get some rep :)
I have been trying for hours finding a way to setup POEdit so that it can grab the text from specific domain only
My gettext function looks like this:
function ri($id, $parameters = array(), $domain = 'default', $locale = null)
A sample call:
echo ri('Text %xyz%', array('%xyz%'=>100), 'myDomain');
I will need to grab only the text with the domain myDomain to translate, or at least I want POEdit to put these texts into domain specific files. Is there a way to do it?
I found several questions that are similar but the answers don't really tell me what to do (I think I'm such a noob it must be explained in plain English for me to understand):
How to set gettext text domain in Poedit?
How to get list of translatable messages
So I finally figured it out after days of searching, I finally found the answer here:
http://sourceforge.net/mailarchive/message.php?msg_id=27691818
xgettext recognizes context in strings, and gives a msgctxt field in the *.pot file, which is recognized by translation software as a
context and is shown as such (check image of Pootle showing context
below)
This can be done in 3 ways:
String in code should be in the format _t('context','string'); and xgettext invocation should be in the form --keyword=_t:1c,2
(this basically explains to xgettext that there are 2 arguments in
the keyword function, 1st one is context, 2nd one is string)
String in code in the format _t('string','context'); and xgettext invocation should be in the form --keyword=_t:1,2c
String in the code should be as _t('context|string') and xgettext invocation should be in the form --keyword=_t:1g
So to answer my own question, I added this to the "sources keywords" tab of Poedit:
ri:1,3c
ri is the function name, 1 is the location of the stringid, 3 is the location of the context/domain
Hope this helps someone else, I hate all these cryptic documents
(This is a repost of my answer to the same thing here.)
Neither GNU gettext tools nor Poedit (which uses them) support this particular misuse of gettext.
In gettext, domain is roughly “a piece of software” — a program, a library, a plugin, a theme. As such, it typically resides in a single directory tree and is alone there — or at the very least, if you have multiple pieces=domains, you have them organized sanely into some subdirectories that you can limit the extraction to.
Mixing and matching domains within a single file as you do is not how gettext was intended to be used, and there’s no reasonable solution to handle it other than using your own helper function, e.g. by wrapping all myDomain texts into __mydomain (which you must define, obviously) and adding that to the list of keywords in Poedit when extracting for myDomain and not adding that to the list of keywords for other domains' files.
I want to write a test framework extension for resharper. The docs for this are here: http://confluence.jetbrains.net/display/ReSharper/Test+Framework+Support
One aspect of this is indicating if a particular piece of code is part of a test. The piece of code is represented as a IDeclaredElement.
Is it possible to get the filename and line number of a piece of code represented by a particular IDeclaredElement?
Following up to the response below:
#Evgeny, thanks for the answer, I wonder if you can clarify one point for me.
Suppose the user has this test open in visual studio: https://github.com/fschwiet/DreamNJasmine/blob/master/NJasmine.Tests/SampleTest.cs
Suppose the user right clicks on line 48, the "player.Resume()" expression.
Will the IDeclaredElement tell me specifically they want to run at line 48? Or is it going to give me a IDeclaredElement corresponding to the entire class, and a filename/line number range for the entire class?
I should play with this myself, but I appreciate tapping into what you already know.
Yes.
The "IDeclaredElement" entity is the code symbol (class, method, variable, etc.). It could be loaded from assembly metadata, it could be declared in source code, it could come from source code implicitly.
You can use
var declarations = declaredElement.GetDeclarations()
to get all AST elements which declares it (this could return multiple declarations for partial class, for example)
Then, for any IDeclaration, you can use
var documentRange = declaration.GetDocumentRange()
if (documentRange.IsValid())
Console.WriteLine ("File: {0} Line:{1}",
DocumentManager.GetInstance(declaration.GetSolution()).GetProjectFile(documentRange.Document).Name,
documentRange.Document.GetCoordsByOffset(documentRange.TextRange.StartOffset).Line
);
By the way, which test framework extension are you developing?
Will the IDeclaredElement tell me specifically they want to run at
line 48?
Once more: IDeclaredElement has no positions in the file. Instead, it's declaration have them.
For every declaration (IDeclaration is a regular AST node) there is range in document which covers it. In my previous example, I used TextRange.StartOffset, though you can use TextRange.EndOffset.
If you need more prcise position in the file, please traverse AST tree, and check the coordinates in the document for specific expression/statement
I'm using the following groovy code to search a file for a string, an account number. The file I'm reading is about 30MB and contains 80,000-120,000 lines. Is there a more efficient way to find a record in a file that contains the given AcctNum? I'm a novice, so I don't know which area to investigate, the toList() or the for-loop. Thanks!
AcctNum = 1234567890
if (testfile.exists())
{
lines = testfile.readLines()
words = lines.toList()
for (word in words)
{
if (word.contains(AcctNum)) { done = true; match = 'YES' ; break }
chunks += 1
if (done) { break }
}
}
Sad to say, I don't even have Groovy installed on my current laptop - but I wouldn't expect you to have to call toList() at all. I'd also hope you could express the condition in a closure, but I'll have to refer to Groovy in Action to check...
Having said that, do you really need it split into lines? Could you just read the whole thing using getText() and then just use a single call to contains()?
EDIT: Okay, if you need to find the actual line containing the record, you do need to call readLines() but I don't think you need to call toList() afterwards. You should be able to just use:
for (line in lines)
{
if (line.contains(AcctNum))
{
// Grab the results you need here
break;
}
}
When you say efficient you usually have to decide which direction you mean: whether it should run quickly, or use as few resources (memory, ...) as possible. Often both lie on opposite sites and you have to pick a trade-off.
If you want to search memory-friendly I'd suggest reading the file line-by-line instead of reading it at once which I suspect it does (I would be wrong there, but in other languages something like readLines reads the whole file into an array of strings).
If you want it to run quickly I'd suggest, as already mentioned, reading in the whole file at once and looking for the given pattern. Instead of just checking with contains you could use indexOf to get the position and then read the record as needed from that position.
I should have explained it better, if I find a record with the AcctNum, I extract out other information on the record...so I thought I needed to split the file into multiple lines.
if you control the format of the file you are reading, the solution is to add in an index.
In fact, this is how databases are able to locate records so quickly.
But for 30MB of data, i think a modern computer with a decent harddrive should do the trick, instead of over complicating the program.