I came across this resource (link to pdf) which lists the EBNF grammar for excel functions. However conversion of such a big ebnf grammar to antlr grammar is time consuming and is giving errors. Are there any resources where we can download ANTLR grammar (preferable the .g4 file) for excel functions ?
Not directly the .g4 file, but there is a paper you can download. The EBNF grammar for excel functions is listed from page 6.
Title: Parsing Excel formulas: A grammar and its application on four
large datasets
Download link: https://fenia266781730.files.wordpress.com/2019/04/smrdoc.pdf#
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I am wondering if I can generate ANTLR grammar from java source code. I want to do some kind of research project, but I am just exploring different open sources to see which one is best.
For ANTLR, do I always have to write a grammar and pass it to the ANTLR?
Is there a way to generate grammar from an existing Java source code?
Not easily. ANTLR generate a recursive descent parser from your grammar, encoding the tests into procedural code, as well as lots of other bookkeeping stuff.
Knowing how the code is generated, you might be able to take it apart but you'll have to reach into the middle of generated statements and that isn't easy without a full parser for the generated language. (Hint: regex won't work).
I don't see a lot of point of this exercise. Why don't you just use the original grammar?
I need to write parser for Bison and Lemon grammar files. I'm looking for specification or grammar of these files format. Any links will be helpful.
It is easy to get a grammar of Bison as it is bootstrapped: just get its parser from the repository.
I'm new to Xtext and wondering what's the purpose of antlr is in xtext. As I've understand so far, antlr generate a parser based on the grammar and the parser then deal with the text models. Right?
And what about the other generated stuff like the editor or the ecore. Are there other components behind xtext which generate them?
Xtext needs a parser generator to produce a parser for the language you define. They could have built one of their own. They chose to use ANTLR instead.
I don't know what other third party machinery they might have chosen to use.
I've been hacking one Xtext based plugin and from what I saw I think it works like this:
Xtext has it's own BNF syntax, which is very similar to ANTLR one. In fact its it's subset.
Xtext takes your grammar, and generates the ANTLR one from it(.g file). The generated ANTLR grammar adds specific actions to your BNF rules. The actions code interacts with the Xtext runtime and (maybe) with the Eclipse itself. The .g file is processed using some older version of ANTLR and .java file is generated. This file is then compiled.
Some tools output an Antlr grammar in a human-unreadable form, at least with ugly placing of parens and indentation. I'd like to transform the grammar into a more readable (standard?) form. The only reference I found is ANTLR pretty printer which is quite old, and looking at its source, it seems to be removing parts of a grammar rather than pretty print it.
How can I format/pretty print a grammar file?
I know of no tool that does this. The one you mentioned, prettyPrinter, is written in - and seems to handle only - ANTLR v2.x grammars, making it unsuitable for v3 grammars.
If you're going to write your own, I'd recommend using the grammar of ANTLR v3 itself to parse a .g grammar file and emit it in a readable form. Terence Parr has posted the grammar here: http://www.antlr.org/grammar/ANTLR
I just installed an Antlr plugin for Eclipse. It can do a lot more than syntax highlight and code formatting...
As an project assignment, I need to parse a plain-C grammar from Java to generate AST output. As a startup, I am using the file c.jj that I have found among grammar files at
http://java.net/projects/javacc/sources/svn/
but I found that it only has syntactic and lexical actions and no real semantics for parsing C source. Is there some other source that incorporate typedef, variables, construct functions, include files?
You could go looking for a complete grammar. Will you learn much this way?
You could ask your lecturer which would impress them more: implementing some small subset of C grammar by writing your own rules, or by searching google for alternative complete rules?
I trust writing your own rules - and even your own hand-crafted parser - will be more a more useful exercise. Even if its only parsing expressions.