How does Atlas find duplicated Nim code if variable names are different?

Atlas uses hybrid semantic and keyword retrieval, indexing Nim code by AST declarations with tree-sitter. This allows it to understand the underlying logic and structure, identifying near-duplicate implementations even when variable names or minor syntax differ, which `grep` cannot do.

Can Atlas ensure my Nim code stays private when searching for duplicates?

Yes, Atlas can build its code index with local Ollama embeddings. This capability ensures that your Nim codebase remains entirely on your local machine, keeping your proprietary code off third-party servers during the search for duplicates.

What Nim testing framework does Atlas integrate with for refactoring?

Atlas integrates directly with Nim's `std/unittest` module. It can run `nimble test` behind a permission prompt after every code modification, ensuring that your test suite passes and no regressions are introduced during the refactoring process.

How does Atlas handle code formatting for Nim after refactoring?

Atlas can invoke `nph`, Nim's official formatter, to automatically format any touched modules after modifications. This ensures that your refactored Nim code adheres to your project's formatting standards, maintaining consistency across the codebase.

Is every change Atlas makes to my Nim files reviewable?

Absolutely. Every Atlas tool call is permission-gated, and it computes a unified diff for every file edit, surfacing it for your approval before writing. Additionally, `apply_patch` creates one reviewable git patch per file, and Atlas snapshots changes for rollback.

Can Atlas help set up `std/unittest` if my Nim project doesn't have it?

Yes, Atlas can assist with this. You can ask Atlas to add a `suite` and `check` block from `std/unittest` under your `tests/` directory, preparing your Nim project for robust testing before commencing refactoring.

How does Atlas know about my Nim project's structure and dependencies?

When run in a directory with a `.nimble` file, Atlas automatically reads your Nim modules, exported symbols marked with an asterisk, and `requires` lines. This allows it to build a comprehensive understanding of your project's structure and dependencies.

Extract a Shared Helper from Duplicated Nim Code with Atlas in 2026

In 2026, Nim developers can efficiently extract shared helpers from duplicated code using Atlas, a terminal-native AI coding agent that integrates directly with the Nim toolchain. Atlas identifies semantically similar code blocks across your project, even when variable names differ, a task where traditional `grep` falls short. It then guides you through creating a new, tested helper module, replacing each duplicate with a call to this new function. This process leverages Nim's `nimble` package manager, the `nimble test` runner for verification, and `nph` for consistent formatting, ensuring that every refactoring step is safe, reviewable, and adheres to Nim's best practices. Atlas provides a unified diff for every change, allowing granular approval before any file is written, making complex refactorings straightforward and secure. This approach ensures your Nim codebase remains robust and maintainable.

How Atlas finds duplicated Nim logic in your codebase

Atlas identifies duplicated Nim logic by leveraging hybrid semantic and keyword retrieval, a significant advancement over simple text-based searches like `grep`. In 2026, Atlas indexes your Nim code using AST declarations via tree-sitter, allowing it to understand the structure and meaning of code blocks, even if variable names or minor syntax differ across 2 or more copies.

When you ask Atlas's `codebase_search` tool for a specific behavior or pattern, it doesn't just look for exact text matches. Instead, it builds an understanding of the code's intent. This is crucial for Nim refactoring, as duplicated logic often has different local variable names or slightly varied expressions. Atlas can build its code index with local Ollama embeddings, ensuring your proprietary Nim code remains off third-party servers. This semantic understanding allows Atlas to surface near-duplicate implementations that `grep` would inevitably miss, providing a comprehensive view of where refactoring opportunities exist within your `nimble` package. This capability ensures that even subtle duplications are identified, paving the way for a cleaner, more maintainable Nim codebase.

Creating a new Nim helper module with Atlas

After identifying duplicated Nim code, Atlas facilitates the creation of a new, shared helper module using its `write` tool. This process is highly controlled: Atlas drafts a plan in a read-only plan agent and asks for approval before switching to a build agent, ensuring you have full oversight of the 1 new file being created.

To create a new Nim helper, you instruct Atlas to `write` the module, specifying its name and location, for example, `src/utils/stringhelpers.nim`. Atlas will then generate the necessary Nim code, including `proc` definitions and any required `import` statements. Before the file is actually written to your disk, Atlas presents a full unified diff of the proposed changes. This permission prompt allows you to review the generated code, suggest modifications, or approve it directly. This ensures that the new helper adheres to your project's coding standards and is correctly integrated into your `nimble` package structure, ready to be used by other modules. The `write` tool's explicit approval step guarantees that no changes are made without your explicit consent.

Replacing duplicated Nim code with helper calls

Once the shared Nim helper module is created, Atlas systematically replaces each instance of the duplicated code with a call to the new helper using the `apply_patch` tool. This critical step is performed one file at a time, generating a distinct git patch for each modification, allowing for granular review of all 3 to 5 changes.

For every location where duplicated Nim logic was found, Atlas will propose a change to replace that block with a call to your newly created helper `proc`. For instance, if `src/moduleA.nim` and `src/moduleB.nim` both contained the same logic, Atlas would generate two separate patches. Each `apply_patch` operation presents a unified diff for your approval, showing exactly what code is being removed and what new helper call is being inserted. This isolated approach means each swap is independently reviewable and revertible, providing maximum safety during complex refactorings. After each successful patch application, Atlas can run `nimble test` to immediately verify that the change hasn't introduced regressions, maintaining the integrity of your Nim codebase and ensuring a smooth transition to the refactored structure.

Ensuring Nim code quality and safety with Atlas

Atlas integrates deeply with the Nim toolchain to ensure every refactoring maintains code quality and stability. After each `apply_patch` operation, Atlas can automatically execute `nimble test` to run your project's `std/unittest` suite, providing immediate feedback on any regressions. This proactive testing is a core safety feature, preventing up to 10 common refactoring errors.

Beyond testing, Atlas also ensures your Nim code remains consistently formatted. After modifying any module, Atlas can invoke `nph`, Nim's official formatter, to automatically apply your project's formatting rules. Every Atlas tool call is permission-gated, meaning you approve each `write`, `apply_patch`, `bash` (for `nimble test`), and `nph` execution. Atlas computes a unified diff for every file edit and surfaces it for approval before writing, and it snapshots file changes as git patches so edits can be diffed and rolled back. This multi-layered approach, combining automated testing, formatting, and explicit user approval, provides a robust safety net for even the most extensive Nim refactorings, ensuring your codebase remains clean, functional, and adheres to best practices.

Setting up Atlas for Nim projects

To begin refactoring your Nim codebase with Atlas, simply run `atlas` within a directory containing a `.nimble` file. Atlas automatically reads your modules, exported symbols marked with an asterisk, and `requires` lines from the `.nimble` file, building a comprehensive understanding of your project's structure in under 1 minute.

Atlas is designed for direct integration with existing Nim projects. Once initialized, Atlas can help you ensure your testing infrastructure is ready. You can ask Atlas to add a `suite` and `check` block from `std/unittest` under your `tests/` directory if one doesn't exist, preparing your project for robust testing. Before committing any changes, Atlas will run `nimble test` behind a permission prompt, allowing you to confirm the test suite passes. This setup ensures that Atlas has a complete context of your Nim project, including its dependencies and testing framework, enabling it to perform intelligent and safe refactorings. Atlas's ability to read `git` branches, status, and diffs further enhances its integration, allowing it to stage and create commits on your behalf, streamlining your development workflow.

Step by step

01Initialize Atlas in your Nim project by running `atlas` in a directory with a `.nimble` file, allowing it to read your modules and dependencies.
02Ask Atlas's `codebase_search` tool for the behavior of the duplicated Nim logic you want to extract, surfacing near-duplicate implementations that `grep` would miss.
03Review each identified Nim code block using Atlas's `read` tool to confirm they are genuinely equivalent and suitable for collapsing into a shared helper.
04Instruct Atlas's `write` tool to create the new shared Nim helper module (e.g., `src/utils/newhelper.nim`), reviewing the full diff in the permission prompt before the file is created.
05For each duplicate, use Atlas's `apply_patch` tool to replace the Nim code with a call to the new helper, approving each file's patch independently for reviewability.
06After every `apply_patch` operation, use Atlas's `bash` tool to run `nimble test`, ensuring your `std/unittest` suite passes and no regressions are introduced.
07Once all duplicates are replaced, use Atlas's `bash` tool to run `nph` to format all touched Nim modules, maintaining code consistency.
08Finally, use Atlas's `grep` tool to search for any surviving copies of the original duplicated Nim logic, confirming a complete refactoring.

Frequently asked questions

How does Atlas find duplicated Nim code if variable names are different?: Atlas uses hybrid semantic and keyword retrieval, indexing Nim code by AST declarations with tree-sitter. This allows it to understand the underlying logic and structure, identifying near-duplicate implementations even when variable names or minor syntax differ, which `grep` cannot do.
Can Atlas ensure my Nim code stays private when searching for duplicates?: Yes, Atlas can build its code index with local Ollama embeddings. This capability ensures that your Nim codebase remains entirely on your local machine, keeping your proprietary code off third-party servers during the search for duplicates.
What Nim testing framework does Atlas integrate with for refactoring?: Atlas integrates directly with Nim's `std/unittest` module. It can run `nimble test` behind a permission prompt after every code modification, ensuring that your test suite passes and no regressions are introduced during the refactoring process.
How does Atlas handle code formatting for Nim after refactoring?: Atlas can invoke `nph`, Nim's official formatter, to automatically format any touched modules after modifications. This ensures that your refactored Nim code adheres to your project's formatting standards, maintaining consistency across the codebase.
Is every change Atlas makes to my Nim files reviewable?: Absolutely. Every Atlas tool call is permission-gated, and it computes a unified diff for every file edit, surfacing it for your approval before writing. Additionally, `apply_patch` creates one reviewable git patch per file, and Atlas snapshots changes for rollback.
Can Atlas help set up `std/unittest` if my Nim project doesn't have it?: Yes, Atlas can assist with this. You can ask Atlas to add a `suite` and `check` block from `std/unittest` under your `tests/` directory, preparing your Nim project for robust testing before commencing refactoring.
How does Atlas know about my Nim project's structure and dependencies?: When run in a directory with a `.nimble` file, Atlas automatically reads your Nim modules, exported symbols marked with an asterisk, and `requires` lines. This allows it to build a comprehensive understanding of your project's structure and dependencies.

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