I am working on a procedural macro which implements a small DSL. Currently I am attempting to implement diagnostics-based error reporting, so that I can provide high quality feedback in the IDE setting.
My overall approach is to use the Diagnostic API of the proc-macro-error crate to create diagnostics.
This API should allow me to emit localized errors like so:
Diagnostic::spanned(span, Level::Error, text).emit();
The problem is, the spanned method takes a proc_macro2::Span as an argument, a struct which has no constructor available.
Based on the nature of the DSL, it is not possible for me to use any Span from the input TokenStream.
How can I create a Span for use in this diagnostic?
spanned method takes Span which is S: MultiSpan
you can use any of those functions to get the span
def_site()
call_site()
mixed_site()
You didn't mention your exact code for better elaboration, so hope the above help
You can also check this link
https://doc.rust-lang.org/proc_macro/struct.Span.html#method.call_site
Is there a way to use hirarchical blocks in redhawk?
For example, say I want to make a digital modulator that is a composition of filters, upsamplers, etc, and I want to use it as a single block in a waveform project, that has other hierarchical components as well. How would I combine the already made filter and upsampler blocks into the digital modulator block using redhawk?
You currently cannot create waveforms of waveforms. A waveform can however have external ports, and external properties allowing you to chain waveforms together dynamically and treat it similar to a component from a programmatic perspective. For example in the example below I launch two waveforms on the domain and connect the two, these waveforms are the examples that come bundled with REDHAWK and have external ports and properties.
>>> from ossie.utils import redhawk
>>> dom = redhawk.attach()
>>> wf1 = dom.createApplication('/waveforms/rh/FM_mono_demo/FM_mono_demo.sad.xml')
>>> wf2 = dom.createApplication('/waveforms/rh/FM_mono_demo/FM_mono_demo.sad.xml')
>>> wf1.connect(wf2)
There isn't a construct for a component of components (other than a waveform). As of the REDHAWK 2.1 beta release there is a 'shared address' construct that allows you to do something similar to what you seem to be asking for. The 'shared address' BULKIO pattern was specifically developed to create high-speed connections between components and reduce the processing load caused by IO. Take a look at https://github.com/RedhawkSDR/core-framework/tree/develop-2.1/docs/shared-address and see if this is what you are looking for. It will allow you to launch 'N' components built according to the shared address pattern into a single component host and still retain each individual components property interfaces etc.
If you are more specific about why you want to use a hierarchical block, a more targeted answer may be possible.
I am trying to extract some features from an audio sample using OpenSMILE, but I'm realizing how difficult it is to set up a config file.
The documentation is not very helpful. The best I could do was run some of the sample config files that are provided, see what came out, and then go into the config file and try to determine where the feature was specified. Here's what I did:
I used the default feature set used from The INTERSPEECH 2010 Paralinguistic Challenge (IS10_paraling.conf).
I ran it over a sample audiofile.
I looked at what came out. Then I read the config file in depth, trying to find out where the feature was specified.
Here's a little markdown table showing the results of my exploration:
| Feature generated | instruction in the conf file |
|-------------------|---------------------------------------------------------|
| pcm_loudness | I see: 'loudness=1' |
| mfcc | I see a section: [mfcc:cMfcc] |
| lspFreq | no matches for the text 'lspFreq' anywhere |
| F0finEnv | I seeF0finalEnv = 1 under [pitchSmooth:cPitchSmoother] |
What I see, is 4 different features, all generated by a different instruction in the config file. Well, for one of them, there was no disconcernable instruction in the config file that I could find. With no pattern or intuitive syntax or apparent system, I have no idea how I can eventually figure out how to specify my own features I want to generate.
There are no tutorials, no YouTube videos, no StackOverflow question and no blog posts out there talking about how this could be done. Which is really surprising since this is obviously a huge part of using OpenSMILE.
If anyone finds this, please, can you advise me on how to create custom config files of OpenSMILE? Thanks!
thanks for your interest in openSMILE and your eagerness to build your own configuration files.
Most users in the scientific community actually use openSMILE for its pre-defined config files for the baseline feature sets, which in version 2.3 are even more flexible to use (more commandline options to output to different file formats etc.).
I admit that the documentation provided is not as good as it could be. However, openSMILE is a very complex piece of Software with a lot of functionality, of which only the most important parts are currently well documented.
The best starting point would be to read the openSMILE book and the SIG'MM tutorials all referenced at http://opensmile.audeering.com/ . It contains a section on how to write configuration files. The next important element is the online help of the binary:
SMILExtract -L lists the available components
SMILExtract -H cComponentName lists all options which a given component supports (and thus also features it can extract) with a short description for each
SMILExtract -configDflt cComponentName gives you a template configuration section for the component with all options listed and defaults set
Due to the architecture of openSMILE, which is centered on incremental processing of all audio features, there is (at least not yet) no easy syntax to define the features you want. Rather, you define the processing chain by adding components:
data sources will read in data (from audio files, csv files, or microphone, for example),
data processors will do signal processing and feature extraction in individual steps (windowing, window function, FFT, magnitudes, mel-spectrum, cepstral coefficients (MFCC), for example for extracting MFCC); for each step there is a data processor.
data sinks will write data to output files or send results to a server etc.
You connect the components via the "reader.dmLevel" and "writer.dmLevel" options. These define a name of a data memory level that the components use to exchange data. Only one component may write to one level, i.e. writer.dmLevel=levelName defines the level and may appear only once. Multiple components can read from this level by setting reader.dmLevel=levelName.
In each component you then set the options to enable computation of features and set parameters for this. To answer your question about lspFreq: This is probably enabled by default in the cLsp component, so you don't see an explicit option for it. For future versions of openSMILE the practice of setting all options explicitly will and should be followed more tightly.
The names of the features in the output will be automatically defined by the components. Often each component adds a part the the name, so you can infer from the name the full chain of processing. The options nameAppend and copyInputName (available to most data processors) control this behaviour, although some components might internally override them or change the behaviour a bit.
To see the names (and other info) for each data memory level, including e.g. which features a component in the configuration produces, you can set the option "printLevelStats=5" in the section of componentInstances:cComponentManager.
As everyhting in openSMILE is built for real-time incremental processing, each data memory level has a buffer, which by default is a ring buffer to keep memory footprint constant when the application runs for a longer time.
Sometimes you might want to summarise features over a window of a given length (e.g. with the cFunctionals component). In this case you must ensure that the buffer size of the input level to this component is large enough to hold the full window. You do this via the following options:
writer.levelconf.isRb = 1/0 : sets type of buffer to ringbuffer (1) or fixed size buffer
writer.levelconf.growDyn = 1/0 : sets the buffer to dynamically grow if more data is written to it (1)
writer.levelconf.nT = sets the size of the buffer in frames. Alternatively you can use bufferSizeSec=x to set the size size in seconds and convert to frames automatically.
In most cases the sizes will be set correctly automatically. Subsequent levels also inherit the configuration from the previous levels. Exceptions are when you set a cFunctionals component to read the full input (e.g. only produce one feature at the end of the file), the you must use growDyn=1 on the level that the functionals component reads from, or if you use a variable framing mode (see below).
The cFunctionals component provides frameMode, frameSize, and frameStep options. Where frameMode can be full* (one vector produced at end of input/file), **list (specify a list of frames), var (receive messages, e.g. from a cTurnDetector component, that define frames on-the-fly), or fix (fixed length window). Only in the case of fix the options frameSize set the size of this window, and frameStep the rate at which the window is shifted forward. In case of fix the buffer size of the input level is set correctly automatically, in the other cases you have to set it manually.
I hope this helps you to get started! With every new openSMILE release we at audEERING are trying to document things a bit better and unify things through various components.
We also welcome contributions from the community (e.g. anybody willing to write a graphical configuration file editor where you drag/drop components and connect them graphically? ;)) - although we know that more documentation will make this easier. Until then, you always have to source code to read ;)
Cheers,
Florian
I recently walked through the Advanced Orchard tutorial on Pluralsight and it really showed me a lot of things I can do to extend Orchard. That said, I was wondering if there is a way for one module to return a view from another module?
The scenario for this is I'm building custom modules for my clients that have features that would be proprietary so I'd want to protect them with an API key, similar to how oForms works. The only difference from mine to theirs is they allow functionality regardless of activation whereas mine wouldn't work at all so I'd like to have a base module that all of my custom modules derive from and each one could do something like:
if (this.IsActivated())
return View("ViewFromThisModule")
else
return View("NotActivatedViewFromBaseModule")
The real purpose behind this would be so I don't have to copy the view(s) utilized in the base module to each custom one for things such as whether the module is activated or not.
Per Betrand's suggestion, instead of going the multiple module route I'll instead do a single module that breaks out features instead. Then I don't need to share anything because the whole thing is self-contained.
I recently heard the term "hook" while talking to some people about a program I was writing. I'm unsure exactly what this term implies although I inferred from the conversation that a hook is a type of function. I searched for a definition but was unable to find a good answer. Would someone be able to give me an idea of what this term generally means and perhaps a small example to illustrate the definition?
Essentially it's a place in code that allows you to tap in to a module to either provide different behavior or to react when something happens.
A hook is functionality provided by software for users of that software to have their own code called under certain circumstances. That code can augment or replace the current code.
In the olden days when computers were truly personal and viruses were less prevalent (I'm talking the '80's), it was as simple as patching the operating system software itself to call your code. I remember writing an extension to the Applesoft BASIC language on the Apple II which simply hooked my code into the BASIC interpreter by injecting a call to my code before any of the line was processed.
Some computers had pre-designed hooks, one example being the I/O stream on the Apple II. It used such a hook to inject the whole disk sub-system (Apple II ROMs were originally built in the days where cassettes were the primary storage medium for PCs). You controlled the disks by printing the ASCII code 4 (CTRL-D) followed by the command you wanted to execute then a CR, and it was intercepted by the disk sub-system, which had hooked itself into the Apple ROM print routines.
So for example, the lines:
PRINT CHR(4);"CATALOG"
PRINT CHR(4);"IN#6"
would list the disk contents then re-initialize the machine. This allowed such tricks as protecting your BASIC programs by setting the first line as:
123 REM XIN#6
then using POKE to insert the CTRL-D character in where the X was. Then, anyone trying to list your source would send the re-initialize sequence through the output routines where the disk sub-system would detect it.
That's often the sort of trickery we had to resort to, to get the behavior we wanted.
Nowadays, with the operating system more secure, it provides facilities for hooks itself, since you're no longer supposed to modify the operating system "in-flight" or on the disk.
They've been around for a long time. Mainframes had them (called exits) and a great deal of mainframe software uses those facilities even now. For example, the free source code control system that comes with z/OS (called SCLM) allows you to entirely replace the security subsystem by simply placing your own code in the exit.
In a generic sense, a "hook" is something that will let you, a programmer, view and/or interact with and/or change something that's already going on in a system/program.
For example, the Drupal CMS provides developers with hooks that let them take additional action after a "content node" is created. If a developer doesn't implement a hook, the node is created per normal. If a developer implements a hook, they can have some additional code run whenever a node is created. This code could do anything, including rolling back and/or altering the original action. It could also do something unrelated to the node creation entirely.
A callback could be thought of as a specific kind of hook. By implementing callback functionality into a system, that system is letting you call some additional code after an action has completed. However, hooking (as a generic term) is not limited to callbacks.
Another example. Sometimes Web Developers will refer to class names and/or IDs on elements as hooks. That's because by placing the ID/class name on an element, they can then use Javascript to modify that element, or "hook in" to the page document. (this is stretching the meaning, but it is commonly used and worth mentioning)
Simple said:
A hook is a means of executing custom code (function) either before, after, or instead of existing code. For example, a function may be written to "hook" into the login process in order to execute a Captcha function before continuing on to the normal login process.
Hooks are a category of function that allows base code to call extension code. This can be useful in situations in which a core developer wants to offer extensibility without exposing their code.
One usage of hooks is in video game mod development. A game may not allow mod developers to extend base functionality, but hooks can be added by core mod library developers. With these hooks, independent developers can have their custom code called upon any desired event, such as game loading, inventory updates, entity interactions, etc.
A common method of implementation is to give a function an empty list of callbacks, then expose the ability to extend the list of callbacks. The base code will always call the function at the same and proper time but, with an empty callback list, the function does nothing. This is by design.
A third party, then, has the opportunity to write additional code and add their new callback to the hook's callback list. With nothing more than a reference of available hooks, they have extended functionality at minimal risk to the base system.
Hooks don't allow developers to do anything that can't be done with other structures and interfaces. They are a choice to be made with consideration to the task and users (third-party developers).
For clarification: a hook allows the extension and may be implemented using callbacks. Callbacks are generally nothing more than a function pointer; the computed address of a function. There appears to be confusion in other answers/comments.
Hooking in programming is a technique employing so-called hooks to make a chain of procedures as an event handler.
Hook denotes a place in the code where you dispatch an event of certain type, and if this event was registered before with a proper function to call back, then it would be handled by this registered function, otherwise nothing happens.
hooks can be executed when some condition is encountered. e.g. some variable changes or some action is called or some event happens. hooks can enter in the process and change things or react upon changes.
Oftentimes hooking refers to Win32 message hooking or the Linux/OSX equivalents, but more generically hooking is simply notifying another object/window/program/etc that you want to be notified when a specified action happens. For instance: Having all windows on the system notify you as they are about to close.
As a general rule, hooking is somewhat hazardous since doing it without understanding how it affects the system can lead to instability or at the very leas unexpected behaviour. It can also be VERY useful in certain circumstances, thought. For instance: FRAPS uses it to determine which windows it should show it's FPS counter on.
A chain of hooks is a set of functions in which each function calls the next. What is significant about a chain of hooks is that a programmer can add another function to the chain at run time. One way to do this is to look for a known location where the address of the first function in a chain is kept. You then save the value of that function pointer and overwrite the value at the initial address with the address of the function you wish to insert into the hook chain. The function then gets called, does its business and calls the next function in the chain (unless you decide otherwise). Naturally, there are a number of other ways to create a chain of hooks, from writing directly to memory to using the metaprogramming facilities of languages like Ruby or Python.
An example of a chain of hooks is the way that an MS Windows application processes messages. Each function in the processing chain either processes a message or sends it to the next function in the chain.
In the Drupal content management system, 'hook' has a relatively specific meaning. When an internal event occurs (like content creation or user login, for example), modules can respond to the event by implementing a special "hook" function. This is done via naming convention -- [your-plugin-name]_user_login() for the User Login event, for example.
Because of this convention, the underlying events are referred to as "hooks" and appear with names like "hook_user_login" and "hook_user_authenticate()" in Drupal's API documentation.
Many answers, but no examples, so adding a dummy one: the following complicated_func offers two hooks to modify its behavior
from typing import List, Callable
def complicated_func(
lst: List[int], hook_modify_element: Callable[[int], int], hook_if_negative=None
) -> int:
res = sum(hook_modify_element(x) for x in lst)
if res < 0 and hook_if_negative is not None:
print("Returning negative hook")
return hook_if_negative
return res
def my_hook_func(x: int) -> int:
return x * 2
if __name__ == "__main__":
res = complicated_func(
lst=[1, 2, -10, 4],
hook_modify_element=my_hook_func,
hook_if_negative=0,
)
print(res)
A function that allows you to supply another function rather than merely a value as an argument, in essence extending it.
In VERY short, you can change the code of an API call such as MessageBox to where it does a different function edited by you (globally will work system wide, locally will work process wide).