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Difftastic: A diff that understands syntax

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Re: Difftastic: A diff that understands syntax

#31

Post by hoseja »

mkdirp wrote: post #20
cjohansson wrote: post #15

If you have consistent code style and formatting this tool is unnecessary. I think that solution is better, you get a more consistent code base that is easier to read for humans. (Also diffs will be faster to compute)

> If you have consistent code style and formatting this tool is unnecessary I disagree. I struggle to replicate it right now using a simple test, but I've seen the following rather infuriating and counter intuitive behaviour from Git/GNU diff. If you have a simple if statement such as: if (bla) { // do something } And you were to add another statement at the end, after the closing curly brace, e.g.: if (bla) { // do…

There is an option [0] to use non-default but still built-in git diff algorithms that might yield better results.

[0] https://git-scm.com/docs/git-diff#Documentation/git-diff.txt...

Re: Difftastic: A diff that understands syntax

#32

Post by cyberge99 »

Nice tool! I've used icdiff for this in the terminal, but I'll see how this performs in my workflow.

Since I use VSCode as my editor, I created this oneliner in my .bash_profile:

# VS Code Diff

diffcb () { "/usr/local/bin/code" -n --diff $@ > /dev/null 2>&1 ; }

With it, I can "diffcb filename1.json filename2.json" to get a visual editor with contextual awareness based on installed lint modules.

Re: Difftastic: A diff that understands syntax

#33

Post by sebdufbeau »

tzahifadida wrote: post #29

how do i install on macbook to try? Can you give some instructions in the getting started?

From https://difftastic.wilfred.me.uk/getting_started.html, it's installed via Cargo, so if you already have Cargo installed its straightforward, otherwise you can install it via https://doc.rust-lang.org/cargo/getting-started/installation...

Re: Difftastic: A diff that understands syntax

#34

Post by lopatin »

YetAnotherNick wrote: post #27
loxias wrote: post #22

This looks really cool and I can't wait to try it, tho... a bit of a PITA to get running. ;) Took a while to figure out how to build, and had to install 400MB of dependencies first.... Edit: And after installing cargo, watching it fail to build, then determining I must need a newer version of cargo, so I built that from source... it fails. Apparently I need to install `rustc-mozilla` and not `rustc`. "obviously". Thi…

Used `cargo install difftastic`? Finished in a minute for me.

Build errors for me. Apparently I'm on some nightly build of cargo, but I need 2021 version. The pain begins...

Edit: Reinstalling Cargo worked!

Re: Difftastic: A diff that understands syntax

#35

Post by loxias »

YetAnotherNick wrote: post #27
loxias wrote: post #22

This looks really cool and I can't wait to try it, tho... a bit of a PITA to get running. ;) Took a while to figure out how to build, and had to install 400MB of dependencies first.... Edit: And after installing cargo, watching it fail to build, then determining I must need a newer version of cargo, so I built that from source... it fails. Apparently I need to install `rustc-mozilla` and not `rustc`. "obviously". Thi…

Used `cargo install difftastic`? Finished in a minute for me.

Sure, but first I had to figure out wtf "cargo" is. :P

Also, `cargo install difftastic` AIUI pulls it from a central location, if I'm gonna poke at software for the first time, I enjoy building it myself first, so I can get my hands dirty in the source. :)

EDIT: Also, the build fails. :(

"error: unexpected token: `include_str` --> /home/loxias/.cargo/registry/src/github.com-1ecc6299db9ec823/radix-heap-0.4.2/src/lib.rs:2:10 | 2 | #![doc = include_str!("../README.md")] | ^^^^^^^^^^^

error: aborting due to previous error

error: could not compile `radix-heap`.

sad trombone

Re: Difftastic: A diff that understands syntax

#36

Post by ziml77 »

Liquid_Fire wrote: post #16
taspeotis wrote: post #3

I paid and used SemanticMerge quite successfully when we had a complex Git workflow with lots of conflicts. https://semanticmerge.com/ Since moving to short lived feature branches it is less useful to me.

SemanticMerge sounded interesting enough so I wanted to check it out, but to my surprise there is no Buy or Download link anywhere on the site. The only thing that might do it is a Login link, but I don't want to create an account just to see how much the thing costs. Is it only sold in bulk to companies? I find it bizarre that there isn't even a "contact sales" button.

That's incredibly annoying! They must have changed something about their pricing and sales model since the time that I had purchased it. I don't understand why companies think that's a good idea. I guess I can't recommend it anymore.

Re: Difftastic: A diff that understands syntax

#37

Post by RyEgswuCsn »

danbruc wrote: post #12
LudwigNagasena wrote: post #6

Is there a good reason why diff tools generally don’t use AST?

Because it is much easier, you don't have to build and maintain parsers for hundreds of languages. And you don't need need just any parser, you need very robust ones that can deal with malformed files well. Or, if you only pick a small set of supported languages, your diff tool will not work on most files or have to fall back to a structure-agnostic algorithm. Also not all text files even follow any useful grammar at…

> And you don't need need just any parser, you need very robust ones that can deal with malformed files well.

I very much agree. I feel there has been a trend recently where people (re)discovered how cool and useful ASTs are and now expect everything be using them. I suspect old-school computer scientists might be secretly laughing at this while programming with some Lisp-like languages they invented for themselves.

Jokes aside, I do wonder how modern IDEs manage to parse broken source code into usable ASTs --- is this trivial (CS theory-wise) or are there a lot of engineering secret sauce involved to make it work?

Re: Difftastic: A diff that understands syntax

#40

Post by conradludgate »

Aicy wrote: post #14

Looks really cool, but there was no instructions on how to install it. I would recommend putting an installation guide in your readme, and it being a full installation guide. I followed the link to your manual and then it told me to install your tool using a tool called "cargo" with no reference on how to install cargo. At this point I gave up. Lazy, maybe, but for a convenience tool like this I want a convenient ins…

Cargo is Rust's build tool/package manager and can be installed easily using rustup. But I would probably suggest the difftastic maintainers add some prebuilt binaries to the releases

(I have an example workflow here if anyone from there is interested https://github.com/conradludgate/wordle/blob/main/.github/wo...)

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