How could I embedded socket in Lua internally, just like oslib, debuglib? - sockets

I want to implement the function like embedding the socket function in my Lua build.
So I don't need to copy socket.core.dll any more (just for fun).
I search the maillist, and see some guys discuss the topic,
http://lua-users.org/lists/lua-l/2005-10/msg00269.html
But I have question for the details steps, who could give me a detailed steps for changing the lua and luasocket code to make them work together (not with dll method).
I tried these steps in windows xp with VC2008:
1) copy luasocket code to Lua project.
2) add some code
static const luaL_Reg lualibs[] = {
{"", luaopen_base},
{LUA_LOADLIBNAME, luaopen_package},
{LUA_TABLIBNAME, luaopen_table},
{LUA_IOLIBNAME, luaopen_io},
{LUA_OSLIBNAME, luaopen_os},
{LUA_STRLIBNAME, luaopen_string},
{LUA_MATHLIBNAME, luaopen_math},
{LUA_DBLIBNAME, luaopen_debug},
{LUA_SOCKETLIBNAME, luaopen_socket_core}, // add this line
{LUA_MIMELIBNAME, luaopen_socket_core}, // add this line
{NULL, NULL}
};
3) build the project, and run it.
When I type print(socket._VERSION), it shows luasocket 2.0.2, it is correct.
When I type print(socket.dns.toip("localhost")), it shows 127.0.0.1 table: 00480AD0, it is correct too.
But when I try to use other features, for example bind, it can't work.
Who could tell me the reason?

you need put luasocket stuff into the package.preload table, in this way:
lua_getfield(L, LUA_GLOBALSINDEX, "package");
lua_getfield(L, -1, "preload");
lua_pushcfunction(L, luaopen_socket_core);
lua_setfield(L, -2, "socket.core");
// add mime.core yourself...

luasocket is a mixed C/lua module, you need to bundle both versions into your application if you want it to work without any extra files.
socket.lua loads socket.core (from socket/core.dll)
mime.lua loads mime.core (from mime/core.dll)
So in order for your application to work you will need to build all the .dll files and the .lua files into your application and manually load them (or set them up to be loaded correctly via custom package loaders).
The email you quoted is tweaking the package.preload table (in a way that appears a tad odd now but might work anyway) to get the built-in C code to be loaded correctly when require is called.

Try running
for k, v in pairs(socket) do print(k, v) end
and maybe we'll be able to help.

Related

Generate starter code based on new file VSCode

Is there a way to configure some code based on a file extension when created in VS Code? I'm currently working with psioniq file header which has been pretty helpful in generating good header files, but I'm looking to take this a step farther.
When I create a new file, based on a specific file extension, I would like it to generate some starting code that I can configure. For example, I work with Verilog a lot. It would be really cool if Code could generate based on the file name.
Create new file
Code generates some code (like below) or something else that could be configured based on the filetype:
module <filename> (
input ,
output ,
);
endmodule
Anyone have any extensions they know about or resources they can point me to to implement this?
This would be a pretty easy extension to write but an alternative is snippets.
You can create keywords, based on the extensions, that when you type it it'll create all that code for you.
https://code.visualstudio.com/docs/editor/userdefinedsnippets

Eclipse Plugin Development: Adding items to a working set with the path of the item?

Hello,
I'm an eclipse plugin development newbie looking for pointers to get me started on a particular project.
I am trying to build an eclipse plugin that will automatically construct a working set from a text file that simply consists of a list of file path names. The files/items need not share any parent directories. The rough idea is represented in the following diagram:
I am not asking for the solution to this task. That's the over-arching goal. To achieve that goal, I want to conquer some smaller goals first.
With that in mind, here's the smaller goal I'm currently trying to tackle:
In Eclipse, how can I prompt the user for a single file's path, and then add that file to an existing working set?
I'm not sure where to start. Should I work directly off of the existing org.eclipse.ui.workingSets extension point? Or should I use a collection of other extension points? How do I convert strings into something that can be added to a working set? Do I write code that directly modifies the workingsets.xml file?
Even with a much simpler goal, I still feel quite overwhelmed with the vastness of eclipse extension options. There are probably many ways to go about implementing something like this, but I just need one to get started.
Thanks a bunch!
To manipulate working sets you use the working set manager interface IWorkingSetManager. Get this with:
IWorkingSetManager manager = PlatformUI.getWorkbench().getWorkingSetManager();
From this you can get a particular working by name with:
IWorkingSet workingSet = manager.getWorkingSet("name");
The contents of a working set is an array of IAdaptable objects:
IAdaptable [] contents = workingSet.getElements();
You add to the contents by adding to this array and setting the contents:
IAdaptable [] newContents
.... get new array with old contents + new contents
workingSet.setElements(newContents);
A lot of Eclipse objects implement IAdaptable, for a file in the workspace you would use IFile. You can use dialogs such as ResourceSelectionDialog to select resources from the workspace.

problems with prefs.get and set ImageJ Macro

I'm trying to write a macro to save preferences and read them after closing and reopening ImageJ.
The saving works, but the macro isn't reading the file. Moreover when I try to use one of these two lines an error occurs that the variable "Prefs" is unknown.
int myNumber = Prefs.get("my.persistent.number", 0);
Prefs.savePreferences();
What am I doing wrong? please help me :-)
The ImageJ macro language itself does not support storing custom preferences. (Only the set of built-in options (accessible via Edit > Options in the menu) can be saved, restored and adjusted.) You need to resort to calling the Java class via call("ij.Prefs.get", "my.persistent.number", "0");.
The following ImageJ macro works in an up-to-date Fiji/ImageJ installation:
myNumber = call("ij.Prefs.get", "my.persistent.number", "0");
print(myNumber);
call("ij.Prefs.set", "my.persistent.number", 3);
In the first run, it prints 0; every following run will print 3; after restarting Fiji, it will print 3 again. In case it does not work for you even after updating to the newest version, please report a bug via Help > Report a bug, which will also submit essential information about your installation to the developers to help them fix the issue.
Using one of the many scripting languages however, you can access the ij.Prefs java class directly, as you are trying to do it. Just do not forget to import the class before using it. This is an example Javascript:
importClass(Packages.ij.Prefs);
myNumber = Prefs.get("my.persistent.number", 0);
Prefs.set("my.persistent.number", myNumber);
Hope that helps.

Issue with a topjson object in a Meteor app built with coffeescript

Apologies for the lack of precision in the question, but I'm not completely sure which of possibly many things I'm doing wrong here.
I'm relatively new to Coffeescript and also geo applications in general, but here goes:
I've got a working (simple) Meteor (.7.0.1) application utilizing coffeescript in both client and server. The issue I'm having occurs when attempting to utilize TopoJSON encoded files to create a layer of US congressional districts. (the purpose of the app is to help highlight voter suppression in the US)
So, a few things: Typically in a non-Meteor app, I would just load the topoJSON file like so:
$.getJSON('./data/us-congress-113.json', function (data) {
var congress_geojson = topojson.feature(data, data.objects.districts);
congress_layer.addData(congress_geojson);
});
Now of course this won't work in Meteor because its not asynchronous.
One of the things that was recommended here on SO was to not worry about reading the file, and to instead change the json file to .js, and then set the contents (which are of course just an object) equal to a variable.
Here's what I did:
First, I changed the .json file to a .js file in the server directory, and added the "congress =" to the beginning of the file. It's a huge file so forgive me for omitting the whole object.
congress = {"type":"Topology",
"objects":
{"districts":
{"type":"GeometryCollection","geometries":[{"type":"Polygon"
Now here's where everything starts to give me issues:
In the server.coffee, I've created a variable like so to reference the congress object:
#congress_geojson = topojson.feature(congress, congress.objects.districts)
Notice how I'm putting the # symbol there? I've been told this allows a variable in Coffeescript to be globally scoped? I tried to also use a Meteor feature called "share" where I declare the variable as "share.congress_geojson". That led to the same issues which I will describe below.
Now in the client.coffee file, I'm trying to call this variable to load into a Leaflet map.
congress_layer = L.geoJson(null,
style:
color: "#DE0404"
weight: 2
opacity: 0.4
fillOpacity: 0.1
)
congress_layer.addData(#congress_geojson)
This isn't working, and specifically (despite attempts to find other ways, the errors I'm getting in the console are:
Exception from Deps afterFlush function: TypeError: Cannot read property 'features' of undefined
at o.GeoJSON.o.FeatureGroup.extend.addData (http://localhost:3000/packages/leaflet.js?ad7b569067d1f68c7403ea1c89a172b4cfd68d85:39:16471)
at Object.Template.map.rendered (http://localhost:3000/client/client.coffee.js?37b1cdc5945f3407f2726a5719e1459f44d1db2d:213:18)
I have no doubt that I'm missing something stupidly obvious here. Any suggestions or tips for what I'm doing completely wrong would be appreciated. Is it a case where an object globally declared in a .js file isn't available to code in a .coffee file? Maybe I'm doing something wrong on the Meteor side?
Thanks!
Edit:
So I was able to get things working by putting the .js file containing the congress object in a root /lib folder, causing the object to load first, and then calling the congress object from the client. However, I'm still wanting to know how I could simply share this object from the server? What is the "Meteor way" here?
If you are looking for the Meteor way to order the loading of files, use the Meteor.startup function and put the initialization code there. That function is the $.ready of the Meteor world, i.e., it will execute only after all your files have been successfully loaded on the client.
So in your case:
Meter.startup ->
congress_layer.addData(#congress_geojson)

How to reliably detect os/platform in Go

Here's what I'm currently using, which I think gets the job done, but there's got to be a better way:
func isWindows() bool {
return os.PathSeparator == '\\' && os.PathListSeparator == ';'
}
As you can see, in my case all I need to know is how to detect windows but I'd like to know the way to detect any platform/os.
Play:
http://play.golang.org/p/r4lYWDJDxL
Detection at compile time
If you're doing this to have different implementations depending on the OS, it is more useful to
have separate files with the implementation of that feature and add build tags to each
of the files. This is used in many places in the standard library, for example in the os package.
These so-called "Build constraints" or "Build tags" are explained here.
Say you have the constant PATH_SEPARATOR and you want that platform-dependent, you
would make two files, one for Windows and one for the (UNIX) rest:
/project/path_windows.go
/project/path_unix.go
The code of these files would then be:
path_windows.go
// +build windows
package project
const PATH_SEPARATOR = '\\'
path_unix.go
// +build !windows
package project
const PATH_SEPARATOR = '/'
You can now access PATH_SEPARATOR in your code and have it platform dependant.
Detection at runtime
If you want to determine the operating system at runtime, use the runtime.GOOS
variable:
if runtime.GOOS == "windows" {
fmt.Println("Hello from Windows")
}
While this is compiled into the runtime and therefore ignores the environment,
you can nevertheless be relatively certain that the value is correct.
The reason for this is that every platform that is worth distinguishing needs
rebuilding due to different executable formats and thus has a new GOOS value.
Have you looked at the runtime package? It has a GOOS const: http://golang.org/pkg/runtime/#pkg-constants
It's 2022 and the correct answer for go 1.18+ is:
At runtime you want:
if runtime.GOOS == "windows" {
// windows specific code here...
}
If you need to determine the filesystem path separator character
Use: os.PathSeparator
Examples:
c:\program files
/usr/local/bin
If you need the Path List separator as used by the PATH environment variable
Use: os.PathListSeparator
Examples:
/usr/local/bin:/usr/local:
"C:\windows";"c:\windows\system32";
Since this is an older question and answer I have found another solution.
You could simply use the constants defined in the os package. This const returns a rune so you would need to use string conversion also.
string(os.PathSeparator)
string(os.PathListSeparator)
Example: https://play.golang.org/p/g6jnF7W5_pJ
I just stumbled on this looking for something else and noticed the age of this post so I'll add a more updated addition. If you're just trying to handle the correct filepath I would use filepath.Join(). Its takes all of the guesswork out of os issues. If there is more you need, other than just filepath, using the runtime constants (runtime.GOOS & runtime.GOARCH) are the way to go: playground example
I tested in Go 1.17.1 which really worked for me.
package main
import (
"fmt"
"runtime"
)
func main(){
fmt.Println(runtime.GOOS)
}
Output:
darwin
With regards to detecting the platform, you can use Distribution Detector project to detect the Linux distribution being run.
The first answer from #nemo is the most apropiate, i just wanted to point out that if you are currently a user of gopls language server the build tags may not work as intended.
There's no solution or workaround up to now, the most you can do is change your editor's lsp configs (vscode, neovim, emacs, etc) to select a build tag in order to being able to edit the files with that tag without errors.
Editing files with another tag will not work, and trying to select multiple tags fails as well.
This is the current progress of the issue github#go/x/tools/gopls