Is there anyway to use the llvm-clang parser in an incremental/online manner?
Say I'm writing an editor and I want to be able to parse the C++ code I have in front of me.
I don't want to write my own hacked up parser.
I'd like to use something full featured, like llvm-clang.
Is there an easy way to hijack the llvm-clang parser? (And is it fast enough to run it continuously in the background)?
Thanks!
I don't think clang can incrementally parse C++ files, but it's one of this project goals: http://clang.llvm.org/features.html
I've written something similar for my final year project. It wasn't C++ editor, but a Visual Studio plugin, which main task was improving C++ intellisense (like Visual Assist X).
When I was writing this project I've been also thinking about C++ incremental parser, but I haven't found any suitable solution. To solve the C++ intellisense problem I used normal C++ parser from GCC. However it was to slow, to parse file after each code completion request (ctrl+space), just try including boost::spirit. To make this project work properly I parsed files in the background and after each code completion request I compared current file with it's previous version (via diff) to detect changes made from last parsing. Having those changes I updated syntax tree, mostly by adding or removing variables.
Except incremental parsing, there is also another problem with projects like this. Mostly you'll be parsing C++ code which is being edited so it's invalid code. Given the complex C++ grammar, sometimes parser won't be able to recover from syntax errors, so it won't detect correctly some symbols in code.
Another issue are C++ parsers / compilers differences. Let's say I'm using working in Visual Studio and I have used some VC++ compiler specific contruction in my code. Clang parser won't be able to parse it correctly.
For writing something similair to IntelliSense, I would advise you to write your own parser using the LALR parsing algorithm. Since you can save its state in each line so you don't have to reparse the whole file when a file has been editted, which is very fast!
Note that C++ can't be fully expressed in BNF, but I think you could get pretty far with some adjustments. It's ofcourse a lot more work than using Clang's frontend, but you could still use Clang for analysing header files in coöperation with you own written parser.
Related
I'd like to derive exactly that subset of the sources of a dart comiler (dart2js or dartdevc or other) or of a dart analyser that can 1. transform a string of dart code (or better a list of strings each representing a compilation unit) into a typed syntax tree, 2. be translated into js, 3. be run in the browser. Is there a marked subset that fulfills these requirements, which is it, and how can I find it, in general.
Accomplishing #1 is fairly simple using package:analyzer, which is the same static analyzer used to provide IDE hinting and autocomplete, etc. The Dart Team is currently working on unifying their compiler frontends behind on main API, but for now, analyzer should definitely take care of most of what you need.
Here's an example of getting a syntax tree and running analysis on it: https://github.com/thosakwe/analyzer_examples/blob/master/analyze_a_file/analyze_a_file.dart
As for #2, you'll likely have to fork the dart-lang/sdk repo and make your own adjustments to dart2js. It's not published as a standalone package. Otherwise, you can write your own compiler, which is probably not going be fun.
I suppose you'd have to figure out how to get #2 up and running, but hypothetically, if you could compile a JavaScript source, you could just eval it after compilation.
To answer your final question, no, AFAIK, there is no subset of dart2js available that lets you create your own Dart-to-JavaScript compiler.
I'm working on a tool that is able to autocomplete the necessary literals defined in a grammar. For example: in C# if a programmer enters: for with a space after it, then it's entirely possible to parse the code, determine that the programmer has started a for statement and autocomplete the necessary punctuation: ( ; ; ).
The more I think about the problem, the more I think there must already be a solution for it, because it's such a common use case, but I can't find anything.
Is there a tool that can do this using a given grammar?
If you don't mind using ANTLR v3 instead of v4 you can use Xtext in order to generate an editor that features auto-complete and error-highlighting. This will happen in form of a plugin for eclipse and apparently also for IntelliJ IDEA.
If you want to use a different IDE or simply want to make use of ANTLR v4's powerfull features you could still have a look at the Xtext Sources as they have to do what you are searching for in order to provide the above mentioned features properly...
This package looks very promising at first glance... You might find the respective code in there.
Be aware though that Xtext is mainly written with Xtend so you either have to do so as well or you have to rewrite it a bit
I want to write a simple editor with basic autocomplete functionality for the Go language as a pet project. How would one go about doing it? I took a look at the Go plugins for Eclipse and IntelliJ, but they were too big for me to comprehend (not to mention getting one to compile).
The Go standard library offers the building blocks for a Go parser which
you can use to parse the source files and look for function definitions and the like.
There's also the godoc command which
already does what you want: extracting method definitions and it's documentation. You may look in the
source code to see how godoc is
working or use godoc directly.
This editor written in Go projects has a manageable amount of code,
you may look into it.
The de facto standard approach to this problem is to use nsf's gocode. I have tried it only in Vim - it works very well.
Even though there's ready made support for specific editors, gocode is not editor specific. It's a daemon with a communication protocol. It is thus usable from any program.
Years ago, I wrote a code template that took a few simple parameters (points) and produced a class skeleton. Since some of the method bodies had code in them, I couldn't call InvokeClassCompletion and just placed the implementations with the declarations (user had to move them).
It has occurred to me that I can write a code template script engine to insert these methods in the correct position, but I don't see how I'm supposed to navigate the file. There are declarations for IOTAEditReader and IOTAEditWriter in ToolsAPI.pas, but I'm guessing there is a step missing - certainly I don't need to manually parse the Delphi code just to find the implementation section?
Does anyone have experience with it?
The IDE has plenty of parsers in it, but not one is made available for IDE plugins (ToolsAPI). So you have to write your own parser or use an existing one like http://delphiblog.twodesk.com/using-the-castalia-delphi-parser
You might find that GExperts or CNPack contains almost all the code you need, in one of its editor wizards.
If not, then, those two are the best reference I know for writing IDE plugins. As far as writing parsers, see Andreas' answer.
If you just want better code templates, you could consider buying Castalia, as it has an improved code template feature over the builtin delphi IDE plugin features. Castalia internally uses the Castalia delphi parser mentioned by andreas. It's quite good.
I'm trying a long-time to find algorithm PSOLA (Pitch Synchronous Overlap Add) or WSOLA (Waveform Similarity Overlap Add) which are Acoustic or Signal Processing Algorithms.
I found it in c++, but I have no experience in c++ and is difficult to pass it to Pascal. Anyone have this code in Pascal or know where to find it to copy?
Something like this example that is in c++
http://sourceforge.net/projects/mffmtimescale/files/v3%20stable/v3.9/WSOLA.v.3.9.zip/download?use_mirror=ufpr
Try the SoundTouch DLL, it comes with a Delphi import unit, so you can use the DLL directly. It should not be too hard to compile it. Just download the free VC++ Express from the MS download site and compile it with that or ask someone with VC++ to compile it for you.
FWIW, who knows, with a few modifications, it might also compile with C++Builder.
About one decade ago, I've used praat in FSeqEdit (Delphi program) to do these type of calculations, but I think the same approach would still work fine today.
I wrote some praat-scripts and execute them via praatcons.exe (console version of praat). You can download the console version from this page:
http://www.fon.hum.uva.nl/praat/download_win.html
That works pretty good.
I usually take this approach:
I manually check what type of conversions and calculations need to be done via the GUI version of praat. Once I find what I need, I create a script for it, and run that with the console version.
Praat is very powerful, so if you didn't know about it yet, make sure to check it out.
There's a page that shows how to work with PSOLA resynthesis here:
http://www.ling.ohio-state.edu/~kyoon/praat-tut/praat-tut2.html
Let me know if you want to see some example code on how to integrate it into your Delphi application (it's pretty straightforward actually).