New embedded programming language with C as a host language
vely.dev
vely.dev
Vely is an embedded programming language with C as a host language. It's precompiled into C, creating a native executable.
Vely empowers C with rich features, simplicity and enhanced safety. It is general-purpose and well-suited for web applications.
Use Vely to rapidly develop high-performance and low-footprint applications
I'm not sure of custom BNF per generating command. I notice they're mostly order independent, which makes it a little easier to learn, but what's the advantage over c syntax? Is it roughly that pointers etc are impossible. Maybe a c-esque syntax would be more learnable
How does the existing syntax compose, i.e. can the user run away with writing tcl-style scripts
If you don't get a lot of feedback, I would guess it is inpart due to custom syntax being an entry barrier to understanding
I don't know, I think html is easy, so people want power with php. On the other hand for an audience that is using c, by the time I'm doing that, does Vely's custom syntax give me more than a set of convenient c library calls... such as https://kristaps.bsd.lv/kcgi/
In any case, I like the apis, and aim, and I think the premise has legs
Vely is also a thin framework that mostly helps with building apps by not having to write Makefile, it will pickup any .v files you got.
And it will generate a dispatcher for requests.
But the framework doesn't do much, only the essentials, and that's by design. After all, C is all about flexibility, and that stays.
Vely is meant to be more human-readable than APIs; it leans more declarative than API. Each statement typically does what a number of C API calls would do, so the idea is to save time by saying what you need done rather than placing a number of API calls. At the same time, it's safer because it handles all the details and has a memory garbage collector.
For instance, web-call does all kinds of GET and POST calls. run-query does SQL queries. write-string composes complex strings. Etc.
Vely is also a thin framework. You can fire up FastCGI application server in minutes, and use the same program to run a command-line program.
Vely has FastCGI built in by default (you can start FastCGI server in seconds with vv/vf), and the output statements (such as @ or p-out) do output to the web (i.e. to the Apache or Nginx reverse proxy) by default.
So you could say in terms of functionality, kcgi is built into Vely transparently.
In terms of additional functionality beyond kcgi, Vely offers
- web constructs (getting input parameters from GET/POST, uploading files, sending files to client with send-file, cookie handling, output to web etc.),
- safer and easier string manipulation,
- database access (mariadb, mysql, postgresql, sqlite) with prepared statements and persistent connections,
- regex (match-pattern),
- exec-program for executing programs,
- file operations,
- encryption/encoding/hashing.
I agree there's a learning curve. I can't say how would people see that, though the idea is to be easier than a traditional API, simply on the account of writing a single statement instead of say 5-10 C API calls.
hopefully not although Slor HN could be a variant of Show HN but for roasting.
I apologize, I don't have specific feedback beyond a vague sense of mild confusion or constructive ideas on how to make it better, hopefully someone else brighter than I can take a crack at it?
/var/lib/vv/bld/stockapp/__stock.o.c
For example, when you see this Vely statement in stock.v (which obviously obtains input parameters from either GET or POST request):
input-param stock_name
All you need to do is look for:
#line 9 "stock.v"
char *stock_name = vey_get_input_param (vey_get_config()->ctx.req, "stock_name")
run-query#add_data@db = "insert into stock (stock_name, stock_price) vaues ('%s', '%s') on duplicate key update stock_price='%s'" : stock_name, stock_price, stock_price
#line 12 "stock.v"
VV_UNUSED (_column_count_add_data);
vely_get_config()->ctx.db->ind_current_db=0;
static void *_sql_prep_add_data_stock_v_649 = NULL;
_is_input_used_add_data[0]=1;
_is_input_used_add_data[1]=1;
_is_input_used_add_data[2]=1;
add_data = "insert into stock (stock_name, stock_price) values ('%s', '%s') on duplicate key update stock_price='%s'";
const char *fname_loc_add_data = "stock.v";
num lnum_add_data = 12;
vely_location (&fname_loc_add_data, &lnum_add_data, 1);
vely_make_SQL (&_sql_buf_add_data, 3, add_data , _is_input_used_add_data[0]==1 ? (stock_name) : NULL , _is_input_used_add_data[1]==1 ? (stock_price) : NULL , _is_input_used_add_data[2]==1 ? (stock_price) : NULL );
if (_qry_executed_add_data == 1) {vely_report_error("Query [add_data] has executed the second time; if you want to execute the same query twice in a row without a loop-query, use different queries with the same query text (or variable) if that is your intention, file [stock.v], line number [12] ");}
_qry_executed_add_data = 1;
vely_execute_SQL (_sql_buf_add_data, &_arow_add_data, (const char**)&_err_add_data, (const char**)&_errm_add_data, 0, 1, 0, &_sql_prep_add_data_stock_v_649, _sql_paramcount_add_data, _sql_params_add_data);
_nrow_add_data=0;
vely_db_free_result ();
vely_free (_sql_buf_add_data);
This way you can see what actual C code is generated for any Vely code.
And you can also step through this code in gdb by using --c-lines option in vv.
There is a lot going on in your big example, and I wouldn't want to have to download and run it first to get a rough mental model of what's happening.
And Vely generates a request dispatcher, which takes the "req" input parameter, which is really the name of the source Vely file. So if "req=mycode", then the function "void mycode()" will execute and it must always be defined in source file mycode.v. This makes it easy to always find the code, and quickly grasp what application does.
Unlike C Makefile, you don't have to write a Makefile. Whatever .v files you have in your source code directory will be automatically picked up and made into an application.
The generated code can and will change. It tries to do the best job of doing what is instructed to do. So if you say:
web-call "http://website.com" response resp response-code rc status len post files "file1"="uploadtest", "file23"="fileup4"
The same goes for exec-program, run-query, send-file, encrypt-data etc etc. All this things you can program yourself in C, but these statements are flexible and will let you quickly and safely do those things. More like "what I want to do" rather than "how I want to do it". Though, like I said, you can examine the generated C code to see exactly how it's done.
The "hello world" tutorial is good for this. And if you do decide to try Vely, I would say try
https://vely.dev/123_hello_world.html
code {
font-family: 'DejaVu Sans Mono';
}
code {
font-family: 'DejaVu Sans Mono', monospace;
}
font-family: monospace;
_ANY_ article about CSS and client side javascript however.. go go go! :)
People have been mucking about with typography since Gutenberg's day and they're not going to stop now.
I'm personally 'font blind', but I don't have a problem with people being creative and making aesthetic choices.
This reminds me of Bjarne Stroustrup's original implementation of C++ which was also transpiled to C. That was known as "Cfront" compiler at the time.
I think of Vely as staying simple, declarative, and C all the way for performance reasons. More of a collection of practical things you'd want to do.
[1] https://vely.dev/language_statements.html "Note that, Vely statements, after translated into C code by vv, are generally made of multiple C statements, hence Vely statements can never be treated as single-line statements." (suggesting that there is no full parser for C-plus-Vely)
By that I mean a direct native executable from either pure C or embedded statement producing shallow and performant C, without layers of other languages intertwined (because in the end anything is always a native executable even if it has layers of byte codes, interpreters, alone or mixed with native extensions).
There's some truth to all of that to some extent.
Making Vely understand C, at least insofar as necessary to prevent issues like this is something that I might add, and it probably wouldn't cost that much. It's definitely worth a look.
From a purely functional perspective, assuming Vely statement is placed properly in a functional context, understanding C (as in parsing and then parsing Vely within) might not bring much benefit. Syntactically speaking, Vely is built to not require much about host language. Though, Vely understands enough to emit meaningful messages, such as in the case of writing:
if (cond) vely_statement
where you will get an error that will prevent code from doing unexpected things. There's quite a few of those safeguards built-in.
Being embedded, Vely is a compromise. That was the goal to preserve pure C performance.
Beyond the above, one can still do anything that C can do and that may not be safe; but if Vely is used for what it does, the chances of that go down. Being able to rapidly do stuff in C that is richer and safer is the plus side of it. Without a compromise with being embedded, it would be yet another language that does everything great but with ever declining performance.
And that is fine, if such loss of performance and increased footprint is acceptable; there is nothing wrong with that. Vely's niche is to stay in best performance bracket, and yet bring that performance to general and web application development.
This means that all the diagnostics being emitted will be very confusing. When incorrect input is given, Vely doesn't produce the error message, gcc does, which makes it difficult to match the error message to what the user actually typed in.
I've used (and created many[1]) "embedded" languages, and this is the biggest problem with those that simply do pattern matching and replacement: the language the programmer is writing is unaware of errors and the programmer has determine what they did wrong by looking at the generated code.
It's not a big problem if the programmer understands this limitation; that the "language" is a macro language that blindly transforms input to output with no understanding of the input. If the programmer accepts this, it can be very useful.
[1] I just created a html preprocessor in bash this morning. It performs variable substitution using environment variables and runs the C preprocessor on the input, allowing #include directives, #ifdef, etc. It lets me write my HTML files in fragments that can conditionally include other HTML files, and it lets me put in variables in the HTML file that are substituted with values from the environment.
I've no doubt that this is a hacky solution, but
a) It took only an hour to write (thus far - there's some TODOs in there for stuff that might be useful in the future)
b) It was quicker than downloading and learning to use an existing tool that does the same thing, and ensuring that all that tools dependencies are brought in as well.
I mentioned in another post that a C program could be parsed to the extent to allow better checking. Not to the point where you'd build a gcc-look-alike, but just enough for instance to know the type of the expression, and if the expression used in Vely statement is correct, and such. Perhaps that's something to consider. I thought about it here and there, but found it to be more useful to check for logical conflicts, such as not providing required arguments, balancing beginning and end of multi-part statement, incorrect usage and such. Typically, using the wrong type accounts for most of the issues, and gcc produces very good messages. Again those messages get matched to the source Vely file exact line number, and I found that correcting an issue isn't difficult.
Your tool sounds great, and if it works what you need it do, awesome! I do things like that all the time, and find that often times using tools is an overkill, and just skip it. There's time and place for everything.
The problem I usually have is matching C-compiler error messages to $NEWLANG errors.
Like I said, as long as the programmer is aware that it's a preprocessor for the language and not an AST-based code generator, then there usually isn't a problem. I used ecl (or gcl, not sure now) that went the AST code-generation path and it worked much better than any preprocessor-based method in terms of compilation errors and diagnostics.
PS. In case you (or anyone else) is wondering about my mentioned HTML preprocessor, I put it into a gist: https://gist.github.com/lelanthran/603a24c56bc3afc1370a007a0...
Hardware drivers, like USB, SPI, etc could be done in C and wiring up things and pushing data around in a more high level language.
After considering micropython for exactly that purpose, I was disappointed because of the implementation complexity and slowness of computations on that platform.
What are your thoughts on this?
After C++, rust is likely the most popular, quite a lot of effort has been put into running rust on embedded, see eg https://github.com/rust-embedded. However, once again to my understanding, industry acceptance is still highly marginal.
After that, there's a bunch of toy-ish efforts to run other languages. Zig, nim, python and javascript variants, etc. Usually anything that has C ABI compatibility should be possible to get up and running (without writing a compiler backend from scratch). I've had fun with some toy projects using nim for ARM cortex-M targets (https://github.com/EmbeddedNim/svd2nim, https://github.com/auxym/nim-on-samd21, https://github.com/EmbeddedNim/picostdlib).
Using Nim (and eg svd2nim to generate the equivalent of CMSIS headers for register access in pure nim), it would be entirely possible to write even the low level stuff (SPI drivers and whatnot) in 100% nim, with the same performance as C and better safety (better static type system and compile-time checks, etc). Runtime (eg overflow) checks and garbage collection are available (at the cost of some performance) but optional. See eg. a pretty basic higher-level API for GPIO access, that provides native performance, since the abstraction is implemented as macros (compile-time abstraction): https://github.com/auxym/nim-on-samd21/blob/master/src/port....
IOT (Internet Of Things) is a major application area for Vely. Obviously what you mentioned may fall into that. But also for example IOT-edge systems, where the communication with multiple near-devices converges, gets processed and then delivered to a cloud server for congregation.
The trick is for Vely to be rich enough to provide the functionality that's typically needed. That is its goal. I hope it's far enough along to be useful, and with time it will get even more so.
Generally, the memory used by Vely statements is created by Vely and you don't have to free it, in fact you shouldn't, it will be freed automatically, even if those pointers are lost or overwritten. The approach is to drastically minimize using C's allocation, and do that only when absolutely necessary, which for most applications should be never.
However, you can still write any C code that does horrible things with memory. Vely exists so you don't have to. The idea is to use Vely to write code that you might otherwise write in pure C and have those issues.
A syntax preprocessor that can be generically applied to multiple libraries
#include "vely.h"
which has to be in every Vely .v file.
Vely is really not a language breakthrough. Not at all.
I would say Vely is a practical workhorse. It is about power of rapidly doing business. Kind of like PHP but more in a declarative way like SQL, within C.
As in, you need a collection of libraries that do all the stuff you need to build an application (run queries, build strings really easy, execute programs, do web calls, deamonize programs etc.).
And you need it without writing C code or using API or procuring libraries and header files, but rather you'd just spill your thoughts about what to do in a language that sounds like a natural language, where even the order of how you say it isn't that important.
They made that one post on GitHub and ran. With no intentions of updating it or correcting its errors, not to interact with anyone, nor to review any other programming languages.
It even refers to an older version of V (0.2 versus 0.3), with various issues that are not even relevant anymore or are their bias one-sided uneducated opinions. It purposely gives readers no balance or an opposing perspective, and is presented with no feedback from Vlang's developers or community (despite having a GitHub account).
Oddly, your account's history and purpose seems to be super laser focused on specifically attacking and trolling anything referring to Vlang.