# Anyone use Positron (data science IDE)? Would you want to use mojo in it? **URL:** \ **Category:** VS Code Extension\ **Created:** [September 27, 2026, 5:54pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531 "2026-09-27T17:54:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![randyzwitch](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/randyzwitch/32/982_2.png) [@randyzwitch](https://forum.modular.com/u/randyzwitch)\ **Post date:** [September 27, 2026, 5:54pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/1 "2026-09-27T17:54:51Z")
While mojo has support for Jupyter Notebooks and VSCode, I’m a bit more comfortable with a fully-featured IDE. [Positron](https://github.com/posit-dev/positron) is one such IDE for data science (don’t know if it matters, but I used to work there…currently no affiliation). Is anyone (besides me) interested in using an IDE like that? I’ve been messing around on my local computer and have a working version, but there are a handful of upstream things that need to be solved to make it a great experience. I opened an issue for one of them, but would love to have a conversation here if something like this is interesting to the community Best, Randy > > > \### Review Mojo's priorities > > \- \[x\] I have read the \[roadmap and priorities\](htt…ps://mojolang.org/docs/roadmap.html#overall-priorities) and I believe this request falls within the priorities. > > \### What is your request? > > Add a machine-readable command to the native Mojo REPL that enumerates its current persistent variables. > > For example: > > \`\`\`text > :mojo variables --format=json > \`\`\` > > Example response: > > \`\`\`json > \[ > { > "name": "answer", > "type": "Int", > "value": "43", > "has\_children": false > } > \] > \`\`\` > > The command should return the current authoritative REPL state rather than declaration history or parsed terminal output. > > I created a working proof of concept here: > > https://github.com/randyzwitch/modular/tree/mojo-repl-variables-json > > The implementation is here: > > https://github.com/randyzwitch/modular/blob/mojo-repl-variables-json/Mojo/lib/MojoLLDB/Commands/CommandObjectMojo.cpp > > It reads variables directly from \`MojoPersistentExpressionState\` and formats their values through LLDB's existing \`SBValue\` support. > > \### What is your motivation for this change? > > I have been playing around with native Mojo support to \[Positron\](https://github.com/posit-dev/positron) (data science IDE/another VSCode fork) through the existing \`modular-mojotools.vscode-mojo\` extension. > > The integration launches \`mojo repl\` directly and connects it to Positron's Console. > > Most Console functionality can be implemented using the existing native REPL interface. However, an IDE Variables pane needs an authoritative way to retrieve the current persistent scope. > > Without this interface, an editor must infer state by parsing human-readable output such as: > > \`\`\`text > (Int) answer = 42 > \`\`\` > > and parsing submitted source such as: > > \`\`\`mojo > answer = 43 > \`\`\` > > That approach cannot reliably handle: > > \- Expression-based assignments such as \`answer = calculate\_value()\` > \- Mutations inside collections and structs > \- Variables created indirectly > \- Failed assignments > \- Nested values > \- Accurate Mojo type and value formatting > > This capability would support native IDE consoles, variable explorers, automated REPL clients, and other tooling without requiring Jupyter or changes specific to Positron. > > \### Any other details? > > The proof of concept demonstrates that the required information is already available inside the REPL. > > It: > > 1. Adds \`mojo variables --format=json\` to the Mojo LLDB command tree. > 2. Reads the current variables from \`MojoPersistentExpressionState\`. > 3. Deduplicates redefined variables so the newest definition wins. > 4. Uses \`SBValue.GetDisplayTypeName()\` for user-facing Mojo types. > 5. Uses LLDB's existing summary/value formatting. > 6. Reports whether a value has children. > 7. Produces JSON without ANSI terminal formatting. > > For example, after: > > \`\`\`mojo > var answer = 42 > \`\`\` > > the command reports: > > \`\`\`json > \[ > { > "has\_children": false, > "name": "answer", > "type": "Int", > "value": "42" > } > \] > \`\`\` > > After: > > \`\`\`mojo > answer = 43 > \`\`\` > > running the command again reports \`"value": "43"\`. This confirms that it reads the current persistent value rather than maintaining separate declaration history. > > The end-to-end REPL test is here: > > https://github.com/randyzwitch/modular/blob/mojo-repl-variables-json/Mojo/test/mojo-repl/variables-command.lldb > > The focused Bazel test passes: > > \`\`\`text > //Mojo/test/mojo-repl:variables-command.lldb.test PASSED > \`\`\` > > Prototype commit: > > https://github.com/randyzwitch/modular/commit/9b67dba > > Possible future extensions include: > > \- A documented, versioned JSON schema > \- Stable access keys > \- Variable length and memory size > \- Child enumeration for structs and collections > \- A command for inspecting a specific variable path > \- Output truncation metadata > \- An explicit protocol/version field > > The minimal top-level command in the prototype is sufficient to replace terminal-output parsing and enable a reliable first version of an IDE Variables pane. ---
**Author:** ![Bodiam](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/bodiam/32/1111_2.png) [@Bodiam](https://forum.modular.com/u/Bodiam)\ **Post date:** [October 4, 2026, 11:39am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/2 "2026-10-04T11:39:04Z")
Hi Randy, I’m not really familiar with Positron, but I’m the developer of Mojo Pro ([https://plugins.jetbrains.com/plugin/31943-mojo-pro](https://plugins.jetbrains.com/plugin/31943-mojo-pro)), which brings support for Mojo 1.0/1.1 to JetBrains IDE’s. It supports things like syntax highlighting, code completion, refactoring, debugging, etc. Would that suit your needs, or is there a special usecase you’re trying to address? Cheers, Erik ---
**Author:** ![randyzwitch](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/randyzwitch/32/982_2.png) [@randyzwitch](https://forum.modular.com/u/randyzwitch)\ **Post date:** [October 4, 2026, 12:59pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/3 "2026-10-04T12:59:00Z")
No, it doesn’t. Positron focuses on data analysis, having panes for charts, a data explorer pane with summary statistics, etc. ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 5, 2026, 12:39pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/4 "2026-10-05T12:39:11Z")
Yeah i would say Positron is mostly for statistics and data analytics and for languages like the R Programming Language. But we’ve had folks like @forfudan implement Mojo for Statisticians and Pythonistas before so he might have an edge on this-pedagogically speaking. And other folks like @kose-y implemented MojoR. ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 5, 2026, 12:44pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/5 "2026-10-05T12:44:23Z")
Positron already supports a VS Code Extension API meaning you can run VS Code extensions directly on it because it natively supports extensions from the Open VSX Registry and standard ``.vsix``files designed for VS Code.. ---
**Author:** ![randyzwitch](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/randyzwitch/32/982_2.png) [@randyzwitch](https://forum.modular.com/u/randyzwitch)\ **Post date:** [October 5, 2026, 2:00pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/6 "2026-10-05T14:00:54Z")
> [@Autark\_pseudo](#): > > Positron already supports a VS Code Extension API meaning you can run VS Code extensions directly on it Sure…my question isn’t one of “Is it possible?”, but rather “Does anyone care?” I have a working prototype on my computer, so if there was wild enthusiasm I’d clean it up and release it. But since there isn’t (yet?), it doesn’t seem like something to take on right now. Even if the cost of creating code is near zero these days, maintaining a community project isn’t… ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 6, 2026, 9:31am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/7 "2026-10-06T09:31:30Z")
Clarifying this… It’s note that we don’t have enthusiasts yet in our community yet it’s basically because not that no one is interested-I’m also quite interested in exploiting new stuff like this. I’ll try installing Positron in my system ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 6, 2026, 9:57am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/8 "2026-10-06T09:57:17Z")
I just installed Positron on my Linux Machine. The “does anyone care” question you asked you can now count me in. Do you have any Open Implementations for this on Data Analytics for Mojo :mojo:? On Positron? ![Screenshot From 2026-10-06 05-49-43](https://us1.discourse-cdn.com/flex001/uploads/modular/original/2X/2/21d2c99458f592f23a5bb0e00672bb62a051a8e6.png) ---
**Author:** ![randyzwitch](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/randyzwitch/32/982_2.png) [@randyzwitch](https://forum.modular.com/u/randyzwitch)\ **Post date:** [October 6, 2026, 12:23pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/9 "2026-10-06T12:23:59Z")
No, I don’t have a publicly available implementation. My local one modifies the Mojo REPL to make the Positron variable explorer work, as well as some changes to the Mojo VSCode plugin. So it would require coordination between both projects. ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 6, 2026, 12:40pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/10 "2026-10-06T12:40:51Z")
Positron works pretty fast though. ![Screenshot From 2026-10-06 08-38-06](https://us1.discourse-cdn.com/flex001/uploads/modular/original/2X/2/2d01822711dae47c16a15f96cac51a0d4100225b.png) ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 6, 2026, 12:42pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/11 "2026-10-06T12:42:39Z")
But Mojo doesn’t seem to read “python” on Interop i don’t know what would be the cause? ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 6, 2026, 12:45pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/12 "2026-10-06T12:45:02Z")
I’ve decided to ditch VS Code I’ll be handling most of my work with Positron. I think it aligns better with my needs. Positron finally works super-well with the Mojo Extension :mojo_nightly: its much faster and better for AI workloads than VS Code; ![Screenshot From 2026-10-06 10-05-40](https://us1.discourse-cdn.com/flex001/uploads/modular/original/2X/6/68c9887a3aa761c149ac26b41f825896445147f9.png) ---
**Author:** ![forfudan](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/forfudan/32/925_2.png) [@forfudan](https://forum.modular.com/u/forfudan)\ **Post date:** [October 9, 2026, 7:41am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/13 "2026-10-09T07:41:36Z")
No, I didn’t use it. 😁 I have only used spyder, jupyter notebook/lab, and VS Code. ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 9, 2026, 11:25am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/14 "2026-10-09T11:25:27Z")
But you have experience with R or Python? ---
**Author:** ![forfudan](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/forfudan/32/925_2.png) [@forfudan](https://forum.modular.com/u/forfudan)\ **Post date:** [October 9, 2026, 11:43am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/15 "2026-10-09T11:43:32Z")
Yes, Python is my main language for daily work (VS Code and Databricks). I don’t use R. Happy to try Positron at some point, but to me Mojo isn’t the best fit for REPL-style work. Python is better at that. I’d rather use Mojo for the backend. ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 9, 2026, 12:43pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/16 "2026-10-09T12:43:47Z")
If i tell you using Positron with Mojo is the most interesting thing I’ve done lately. The REPL-style sheeting gives me a much better Machine Learning workspace yet it works faster and way more efficient than running my ML models in some IDE like VS Code or Cursor. Would you stick to this? And i would say Mojo is pretty snappy in positron its much better when i do data analysis or basic big data analytics. So claiming Python is much better than Mojo in this isn’t what someone like me would say in a pedagogical analogy. You can explain further why you claim so? ---
**Author:** ![Autark\_pseudo](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/autark_pseudo/32/1297_2.png) [@Autark\_pseudo](https://forum.modular.com/u/Autark_pseudo)\ **Post date:** [October 9, 2026, 12:49pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/17 "2026-10-09T12:49:17Z")
While Modular deprecated standard REPL features in certain nightly toolchains to prioritize core GPU/compiler pipelines, the underlying execution architecture is designed specifically to support dynamic, line-by-line JIT execution. ---
**Author:** ![MMabrouk](https://avatars.discourse-cdn.com/v4/letter/m/3ec8ea/32.png) [@MMabrouk](https://forum.modular.com/u/MMabrouk)\ **Post date:** [October 10, 2026, 5:32am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/18 "2026-10-10T05:32:48Z")
I use positron semi-regularly. it is quite nice for visualization and mixed R and python work. I didn’t really have the thought to try mojo in it, but if you are willing to share the mojo extension, I can give it a try. ---
**Author:** ![forfudan](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/forfudan/32/925_2.png) [@forfudan](https://forum.modular.com/u/forfudan)\ **Post date:** [October 10, 2026, 10:15am UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/19 "2026-10-10T10:15:52Z")
Glad it works well for you. I will also give it a try. About my point. I value workflow and reliability more than raw speed. For interactive work, I prefer dynamic typing, no compile step, and a mature ecosystem, which is where Python shines. Python packages have been tested for years on edge cases, while Mojo is still young and evolving quickly. Building a library in Mojo and debugging all the edge cases is not something that can easily be done in a REPL, so I prefer VS Code for a better sense of control. By the way, the IDE itself doesn’t change execution speed. I’m not a fan of Mojo’s REPL mode. What I value more in Mojo is its memory safety, its syntax similarity to Python, and its nice interoperability with Python. I’m curious to see where Mojo + Positron goes, though. ---
**Author:** ![randyzwitch](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/randyzwitch/32/982_2.png) [@randyzwitch](https://forum.modular.com/u/randyzwitch)\ **Post date:** [October 10, 2026, 3:09pm UTC](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531/20 "2026-10-10T15:09:29Z")
Thanks everyone, looks like there is some interest, so I’ll pursue getting the changes into the Mojo REPL that will make Positron work better with Mojo [Next page](https://forum.modular.com/t/anyone-use-positron-data-science-ide-would-you-want-to-use-mojo-in-it/3531.md?page=2)