reformat

A modular code transformation framework. Each transformer handles one concern -- renaming files, normalising whitespace, converting identifier case, etc. -- and the pipeline system lets you compose them into multi-step workflows that run in a single invocation.

Features

Modular transformers

Every transformation is an independent module with its own options struct, sensible defaults, and a consistent interface (process(path) -> Result). Transformers can be used standalone via CLI subcommands, composed into pipelines, or called directly as a Rust library from reformat-core.

Transformer	CLI subcommand	What it does
`FileRenamer`	`rename_files`	Case transforms, prefix/suffix operations, timestamps on filenames
`CaseConverter`	`convert`	Convert identifiers between 6 case formats (camel, pascal, snake, screaming snake, kebab, screaming kebab)
`WhitespaceCleaner`	`clean`	Strip trailing whitespace while preserving line endings
`EmojiTransformer`	`emojis`	Replace task/status emojis with text alternatives, remove decorative emojis
`FileGrouper`	`group`	Organise files by common prefix into subdirectories, detect and fix broken references
`EndingsNormalizer`	`endings`	Normalise line endings to LF, CRLF, or CR (skips binary files automatically)
`IndentNormalizer`	`indent`	Convert between tabs and spaces with configurable width, tab-stop-aware
`ContentReplacer`	`replace`	Regex find-and-replace with capture group support, multiple sequential patterns
`HeaderManager`	`header`	Insert or update file headers (license, copyright) with year templating

All transformers share common behaviours: recursive directory traversal, file extension filtering, dry-run mode, and automatic skipping of hidden files and build directories (.git, node_modules, target, __pycache__, etc.).

Pipelines: presets and jobs

Transformers become more useful when composed. The pipeline system chains any combination of the above steps and runs them in order on the same path.

There are two ways to define a pipeline, reflecting two different needs:

Presets (-p) -- Reusable, named pipelines stored in reformat.json at the project root. Version-controlled, shared across a team, run repeatedly.
Jobs (--job) -- Ad-hoc, throwaway pipelines loaded from any file or stdin. No project config needed. Ideal for one-off migrations, scripted CI transforms, or quick multi-pattern replacements.

Both use the same JSON format (a steps array plus per-step config) and the same execution engine. The only difference is where they are stored.

{
  "steps": ["endings", "indent", "clean", "header"],
  "endings": { "style": "lf" },
  "indent": { "style": "spaces", "width": 4 },
  "header": {
    "text": "// Copyright {year} MyOrg. All rights reserved.",
    "update_year": true,
    "file_extensions": [".rs", ".go"]
  }
}

# As a reusable preset (stored in reformat.json under a name):
reformat -p normalize src/

# As a throwaway job (from a file):
reformat --job normalize.json src/

# As a throwaway job (piped from stdin):
cat normalize.json | reformat --job - src/

Quick processing (default command)

For the common case of cleaning up a directory, reformat <path> runs three transformations in a single optimised pass -- rename to lowercase, replace task emojis, strip trailing whitespace -- without needing a config file.

Library-first design

The project is organised as a Cargo workspace:

reformat-core -- All transformation logic. Every struct and option type is a public API. Use this crate directly if you want programmatic access.
reformat-cli -- Thin CLI wrapper using clap. Parses arguments, loads config, calls into core.
reformat-plugins -- Plugin system foundation (not yet active).

Observability

Multi-level verbosity (-v, -vv, -vvv), quiet mode (-q), file logging (--log-file)
Progress spinners, automatic operation timing, colour-coded output
Dry-run mode on every transformer and every pipeline step

Installation

Install from crates.io:

cargo install reformat

Or install from the workspace:

cargo install --path reformat-cli

Or build from source:

cargo build --release -p reformat

The binary will be at ./target/release/reformat

Library Usage

Add to your Cargo.toml:

[dependencies]
reformat-core = "0.1.6"

Case Conversion

use reformat_core::{CaseConverter, CaseFormat};

let converter = CaseConverter::new(
    CaseFormat::CamelCase,    // from
    CaseFormat::SnakeCase,    // to
    None,                     // file_extensions
    false,                    // recursive
    false,                    // dry_run
    String::new(),            // prefix
    String::new(),            // suffix
    None,                     // strip_prefix
    None,                     // strip_suffix
    None,                     // replace_prefix_from
    None,                     // replace_prefix_to
    None,                     // replace_suffix_from
    None,                     // replace_suffix_to
    None,                     // glob_pattern
    None,                     // word_filter
)?;

converter.process_directory(std::path::Path::new("src"))?;

Whitespace Cleaning

use reformat_core::{WhitespaceCleaner, WhitespaceOptions};

let mut options = WhitespaceOptions::default();
options.dry_run = false;
options.recursive = true;

let cleaner = WhitespaceCleaner::new(options);
let (files_cleaned, lines_cleaned) = cleaner.process(std::path::Path::new("src"))?;
println!("Cleaned {} lines in {} files", lines_cleaned, files_cleaned);

Combined Processing (Default Command)

use reformat_core::{CombinedProcessor, CombinedOptions};

let mut options = CombinedOptions::default();
options.recursive = true;
options.dry_run = false;

let processor = CombinedProcessor::new(options);
let stats = processor.process(std::path::Path::new("src"))?;

println!("Files renamed: {}", stats.files_renamed);
println!("Emojis transformed: {} files ({} changes)",
         stats.files_emoji_transformed, stats.emoji_changes);
println!("Whitespace cleaned: {} files ({} lines)",
         stats.files_whitespace_cleaned, stats.whitespace_lines_cleaned);

Line Ending Normalization

use reformat_core::{EndingsNormalizer, EndingsOptions, LineEnding};

let options = EndingsOptions {
    style: LineEnding::Lf,
    recursive: true,
    dry_run: false,
    ..Default::default()
};

let normalizer = EndingsNormalizer::new(options);
let (files, endings) = normalizer.process(std::path::Path::new("src"))?;
println!("Normalized {} endings in {} files", endings, files);

Indentation Normalization

use reformat_core::{IndentNormalizer, IndentOptions, IndentStyle};

let options = IndentOptions {
    style: IndentStyle::Spaces,
    width: 4,
    recursive: true,
    dry_run: false,
    ..Default::default()
};

let normalizer = IndentNormalizer::new(options);
let (files, lines) = normalizer.process(std::path::Path::new("src"))?;
println!("Normalized {} lines in {} files", lines, files);

Regex Find-and-Replace

use reformat_core::{ContentReplacer, ReplaceOptions, ReplacePattern};

let options = ReplaceOptions {
    patterns: vec![
        ReplacePattern {
            find: r"old_api\(".to_string(),
            replace: "new_api(".to_string(),
        },
    ],
    recursive: true,
    dry_run: false,
    ..Default::default()
};

let replacer = ContentReplacer::new(options)?;
let (files, replacements) = replacer.process(std::path::Path::new("src"))?;
println!("Made {} replacements in {} files", replacements, files);

File Header Management

use reformat_core::{HeaderManager, HeaderOptions};

let options = HeaderOptions {
    text: "// Copyright {year} MyOrg. All rights reserved.\n// SPDX-License-Identifier: MIT".to_string(),
    update_year: true,
    recursive: true,
    dry_run: false,
    ..Default::default()
};

let manager = HeaderManager::new(options)?;
let (files, _) = manager.process(std::path::Path::new("src"))?;
println!("Updated headers in {} files", files);

File Grouping

use reformat_core::{FileGrouper, GroupOptions};

let mut options = GroupOptions::default();
options.strip_prefix = true;  // Remove prefix from filenames
options.from_suffix = false;  // Set true to split at LAST separator
options.min_count = 2;        // Require at least 2 files to create a group
options.dry_run = false;

let grouper = FileGrouper::new(options);
let stats = grouper.process(std::path::Path::new("templates"))?;

println!("Directories created: {}", stats.dirs_created);
println!("Files moved: {}", stats.files_moved);
println!("Files renamed: {}", stats.files_renamed);

Quick Start

Default Command (Recommended)

The fastest way to clean up your code:

# Process directory (non-recursive)
reformat <path>

# Process recursively
reformat -r <path>

# Preview changes without modifying files
reformat -d <path>

What it does:

Renames files to lowercase
Transforms task emojis: ✅ → [x], ☐ → [ ]
Removes trailing whitespace

Example:

# Clean up an entire project directory
reformat -r src/

# Preview changes first
reformat -d -r docs/

# Process a single file
reformat README.md

Output:

Renamed '/tmp/TestFile.txt' -> '/tmp/testfile.txt'
Transformed emojis in '/tmp/testfile.txt'
Cleaned 2 lines in '/tmp/testfile.txt'
Processed files:
  - Renamed: 1 file(s)
  - Emoji transformations: 1 file(s) (1 changes)
  - Whitespace cleaned: 1 file(s) (2 lines)

Usage

Case Conversion

Basic conversion (using subcommand):

reformat convert --from-camel --to-snake myfile.py

Recursive directory conversion:

reformat convert --from-snake --to-camel -r src/

Dry run (preview changes):

reformat convert --from-camel --to-kebab --dry-run mydir/

Add prefix to all converted identifiers:

reformat convert --from-camel --to-snake --prefix "old_" myfile.py

Filter files by pattern:

reformat convert --from-camel --to-snake -r --glob "*test*.py" src/

Only convert specific identifiers:

reformat convert --from-camel --to-snake --word-filter "^get.*" src/

Whitespace Cleaning

Clean all default file types in current directory:

reformat clean .

Clean with dry-run to preview changes:

reformat clean --dry-run src/

Clean only specific file types:

reformat clean -e .py -e .rs src/

Clean a single file:

reformat clean myfile.py

Emoji Transformation

Replace task emojis with text in markdown files:

reformat emojis docs/

Process with dry-run to preview changes:

reformat emojis --dry-run README.md

Only replace task emojis, keep other emojis:

reformat emojis --replace-task --no-remove-other docs/

Process specific file types:

reformat emojis -e .md -e .txt project/

File Grouping

Organize files by common prefix into subdirectories:

# Preview what groups would be created
reformat group --preview templates/

# Dry run to see what would happen
reformat group --dry-run templates/

# Group files (keep original filenames)
reformat group templates/

# Group files and strip prefix from filenames
reformat group --strip-prefix templates/

# Group by suffix (split at LAST separator) - for multi-part prefixes
reformat group --from-suffix templates/

# Process subdirectories recursively
reformat group -r templates/

# Use custom separator (e.g., hyphen)
reformat group -s '-' templates/

# Require at least 3 files to create a group
reformat group -m 3 templates/

Example transformation with --strip-prefix (splits at FIRST separator):

Before:                          After:
templates/                       templates/
├── wbs_create.tmpl             ├── wbs/
├── wbs_delete.tmpl             │   ├── create.tmpl
├── wbs_list.tmpl               │   ├── delete.tmpl
├── work_package_create.tmpl    │   └── list.tmpl
├── work_package_delete.tmpl    ├── work/
└── other.txt                   │   ├── package_create.tmpl
                                │   └── package_delete.tmpl
                                └── other.txt

Example transformation with --from-suffix (splits at LAST separator):

Before:                                    After:
templates/                                 templates/
├── activity_relationships_list.tmpl      ├── activity_relationships/
├── activity_relationships_create.tmpl    │   ├── list.tmpl
├── activity_relationships_delete.tmpl    │   ├── create.tmpl
├── user_profile_edit.tmpl                │   └── delete.tmpl
├── user_profile_view.tmpl                ├── user_profile/
└── other.txt                             │   ├── edit.tmpl
                                          │   └── view.tmpl
                                          └── other.txt

Broken Reference Detection

After grouping files, reformat can scan your codebase for broken references:

# Interactive mode (default) - prompts for scanning
reformat group --strip-prefix templates/

# Output:
# Grouping complete:
#   - Directories created: 2
#   - Files moved: 5
# 
# Changes recorded to: changes.json
# 
# Would you like to scan for broken references? [y/N]: y
# Enter directories to scan: src
# 
# Found 3 broken reference(s).
# Proposed fixes written to: fixes.json
# 
# Review fixes.json and apply changes? [y/N]: y
# Fixed 3 reference(s) in 2 file(s).

# Non-interactive mode with automatic scanning
reformat group --strip-prefix --no-interactive --scope src templates/

# Skip reference scanning entirely
reformat group --strip-prefix --no-interactive templates/

Generated files:

changes.json - Record of all file operations (for auditing)
fixes.json - Proposed reference fixes (review before applying)

Line Ending Normalization

Normalize line endings across files:

# Convert to Unix line endings (LF) - default
reformat endings src/

# Convert to Windows line endings (CRLF)
reformat endings --style crlf src/

# Preview changes
reformat endings --dry-run src/

# Process specific file types
reformat endings -e .py -e .rs src/

Indentation Normalization

Convert between tabs and spaces:

# Convert tabs to spaces (4-wide, default)
reformat indent src/

# Convert tabs to 2-space indentation
reformat indent --style spaces --width 2 src/

# Convert spaces to tabs
reformat indent --style tabs --width 4 src/

# Preview changes
reformat indent --dry-run src/

Regex Find-and-Replace

Apply regex patterns across files:

# Simple text replacement
reformat replace --find "old_name" --replace-with "new_name" src/

# Regex with capture groups
reformat replace --find "func\((\w+), (\w+)\)" --replace-with "func(\$2, \$1)" src/

# Dry run
reformat replace --find "TODO" --replace-with "FIXME" --dry-run src/

# Filter by extension
reformat replace --find "2024" --replace-with "2025" -e .py src/

For multiple patterns, use a preset (see Presets section below).

File Header Management

Insert or update file headers:

# Insert a license header
reformat header --text "// Copyright 2025 MyOrg\n// SPDX-License-Identifier: MIT" src/

# Insert header with automatic year
reformat header --text "// Copyright {year} MyOrg" --update-year src/

# Preview changes
reformat header --text "// Header" --dry-run src/

# Process specific file types
reformat header --text "# License" -e .py src/

Presets

Define reusable transformation pipelines in a reformat.json file in your project root:

{
  "code": {
    "steps": ["rename", "emojis", "clean"],
    "rename": {
      "case_transform": "lowercase",
      "space_replace": "hyphen"
    },
    "emojis": {
      "replace_task_emojis": true,
      "remove_other_emojis": false,
      "file_extensions": [".md", ".txt"]
    },
    "clean": {
      "remove_trailing": true,
      "file_extensions": [".rs", ".py"]
    }
  },
  "templates": {
    "steps": ["group", "clean"],
    "group": {
      "separator": "_",
      "min_count": 3,
      "strip_prefix": true
    }
  }
}

Run a preset:

reformat -p code src/

# Dry-run to preview changes
reformat -p code -d src/

# Run a different preset
reformat -p templates web/templates/

Available step configuration options:

Step	Options
`rename`	`case_transform` (lowercase/uppercase/capitalize), `space_replace` (underscore/hyphen), `recursive`, `include_symlinks`
`emojis`	`replace_task_emojis`, `remove_other_emojis`, `file_extensions`, `recursive`
`clean`	`remove_trailing`, `file_extensions`, `recursive`
`convert`	`from_format`, `to_format`, `file_extensions`, `recursive`, `prefix`, `suffix`, `glob`, `word_filter`
`group`	`separator`, `min_count`, `strip_prefix`, `from_suffix`, `recursive`
`endings`	`style` (lf/crlf/cr), `file_extensions`, `recursive`
`indent`	`style` (spaces/tabs), `width`, `file_extensions`, `recursive`
`replace`	`patterns` (array of `{find, replace}`), `file_extensions`, `recursive`
`header`	`text`, `update_year`, `file_extensions`, `recursive`

Steps without explicit configuration use sensible defaults.

Example preset using new transformers:

{
  "normalize": {
    "steps": ["endings", "indent", "clean", "header"],
    "endings": { "style": "lf" },
    "indent": { "style": "spaces", "width": 4 },
    "header": {
      "text": "// Copyright {year} MyOrg. All rights reserved.\n// SPDX-License-Identifier: MIT",
      "update_year": true,
      "file_extensions": [".rs", ".go", ".js"]
    }
  },
  "migrate-api": {
    "steps": ["replace"],
    "replace": {
      "patterns": [
        { "find": "old_api\\(", "replace": "new_api(" },
        { "find": "Copyright 2024", "replace": "Copyright 2025" }
      ],
      "file_extensions": [".rs", ".py"]
    }
  }
}

Jobs

Jobs are ad-hoc transformation pipelines for one-off tasks. A job file has the same format as a single preset -- just a JSON object with steps and per-step config -- but is loaded from an arbitrary file (or stdin) instead of your project's reformat.json.

Run a job from a file:

reformat --job migrate.json src/

Run a job from stdin:

echo '{"steps":["clean"]}' | reformat --job - src/

Example job file for a multi-pattern replacement:

{
  "steps": ["replace", "clean"],
  "replace": {
    "patterns": [
      {"find": "old_api\\(", "replace": "new_api("},
      {"find": "Copyright 2024", "replace": "Copyright 2025"}
    ],
    "file_extensions": [".rs", ".py"]
  }
}

Jobs support dry-run mode:

reformat --job migrate.json --dry-run src/

When to use presets vs. jobs:

	Presets (`-p`)	Jobs (`--job`)
Source	`reformat.json` in project root	Any file or stdin
Lifecycle	Reusable, version-controlled	Throwaway, ad-hoc
Use case	Standard project workflows	One-off migrations, scripted transforms

Logging and Debugging

Control output verbosity:

# Info level output (-v)
reformat -v convert --from-camel --to-snake src/

# Debug level output (-vv)
reformat -vv clean src/

# Silent mode (errors only)
reformat -q convert --from-camel --to-snake src/

# Log to file
reformat --log-file debug.log -v convert --from-camel --to-snake src/

Output example with -v:

2025-10-10T00:15:08.927Z [INFO] Converting from CamelCase to SnakeCase
2025-10-10T00:15:08.927Z [INFO] Target path: /tmp/test.py
2025-10-10T00:15:08.927Z [INFO] Recursive: false, Dry run: false
Converted '/tmp/test.py'
2025-10-10T00:15:08.931Z [INFO] Conversion completed successfully
2025-10-10T00:15:08.931Z [INFO] run_convert(), Elapsed=4.089125ms

Case Format Options

--from-camel / --to-camel - camelCase (firstName, lastName)
--from-pascal / --to-pascal - PascalCase (FirstName, LastName)
--from-snake / --to-snake - snake_case (first_name, last_name)
--from-screaming-snake / --to-screaming-snake - SCREAMING_SNAKE_CASE (FIRST_NAME, LAST_NAME)
--from-kebab / --to-kebab - kebab-case (first-name, last-name)
--from-screaming-kebab / --to-screaming-kebab - SCREAMING-KEBAB-CASE (FIRST-NAME, LAST-NAME)

Examples

Case Conversion Examples

Convert Python file from camelCase to snake_case:

reformat convert --from-camel --to-snake main.py

Convert C++ project from snake_case to PascalCase:

reformat convert --from-snake --to-pascal -r -e .cpp -e .hpp src/

Preview converting JavaScript getters to snake_case:

reformat convert --from-camel --to-snake --word-filter "^get.*" -d src/

Whitespace Cleaning Examples

Clean trailing whitespace from entire project:

reformat clean -r .

Clean only Python files in src directory:

reformat clean -e .py src/

Preview what would be cleaned without making changes:

reformat clean --dry-run .

Emoji Transformation Examples

Transform task emojis in documentation:

reformat emojis -r docs/

Example transformation:

Before:

- Task done ✅
- Task pending ☐
- Warning ⚠ issue
- 🟡 In progress
- 🟢 Complete
- 🔴 Blocked

After:

- Task done [x]
- Task pending [ ]
- Warning [!] issue
- [yellow] In progress
- [green] Complete
- [red] Blocked

Process only markdown files:

reformat emojis -e .md README.md

File Grouping Examples

Organize template files by prefix (split at first separator):

reformat group --strip-prefix web/templates/

Organize files with multi-part prefixes (split at last separator):

# activity_relationships_list.tmpl -> activity_relationships/list.tmpl
reformat group --from-suffix web/templates/

Preview groups without making changes:

reformat group --preview web/templates/

Example output:

Found 2 potential group(s):

  wbs (3 files):
    - wbs_create.tmpl
    - wbs_delete.tmpl
    - wbs_list.tmpl

  work (2 files):
    - work_package_create.tmpl
    - work_package_delete.tmpl

Group files with hyphen separator:

reformat group -s '-' --strip-prefix components/

Recursively organize nested directories:

reformat group -r --strip-prefix src/

Group files and automatically scan for broken references:

reformat group --strip-prefix --scope src templates/

Example changes.json:

{
  "operation": "group",
  "timestamp": "2026-01-15T16:30:00+00:00",
  "base_dir": "/project/templates",
  "changes": [
    {"type": "directory_created", "path": "wbs"},
    {"type": "file_moved", "from": "wbs_create.tmpl", "to": "wbs/create.tmpl"}
  ]
}

Example fixes.json:

{
  "generated_from": "changes.json",
  "fixes": [
    {
      "file": "src/handler.go",
      "line": 15,
      "context": "template.ParseFiles(\"wbs_create.tmpl\")",
      "old_reference": "wbs_create.tmpl",
      "new_reference": "wbs/create.tmpl"
    }
  ]
}

Line Ending Normalization Examples

Normalize a cross-platform project to Unix endings:

reformat endings -r src/

Convert to Windows line endings for distribution:

reformat endings --style crlf -r dist/

Indentation Normalization Examples

Standardize a project to 4-space indentation:

reformat indent -r src/

Convert to 2-space indentation for JavaScript:

reformat indent --width 2 -e .js -e .ts src/

Convert to tabs:

reformat indent --style tabs --width 4 -e .go src/

Regex Find-and-Replace Examples

Update copyright year across all files:

reformat replace --find "Copyright 2024" --replace-with "Copyright 2025" -r .

Swap function argument order using capture groups:

reformat replace --find "swap\((\w+), (\w+)\)" --replace-with "swap(\$2, \$1)" src/

File Header Examples

Add MIT license header to all Rust files:

reformat header -t "// Copyright {year} MyOrg\n// SPDX-License-Identifier: MIT" --update-year -e .rs src/

Ensure all Python files have a header (preserves shebang):

reformat header -t "# Copyright {year} MyOrg" --update-year -e .py src/

Preset Examples

Run a multi-step cleanup preset:

# Define in reformat.json, then run:
reformat -p code src/

# Output:
#   rename: 3 file(s) renamed
#   emojis: 2 file(s), 5 change(s)
#   clean: 4 file(s), 12 line(s) cleaned
# Preset 'code' complete.

Preview preset changes without modifying files:

reformat -p code -d src/

Case conversion preset:

{
  "snake-to-camel": {
    "steps": ["convert"],
    "convert": {
      "from_format": "snake",
      "to_format": "camel",
      "file_extensions": [".py"],
      "recursive": true
    }
  }
}

reformat -p snake-to-camel src/

License

MIT License. See LICENSE for details.

Name		Name	Last commit message	Last commit date
Latest commit History 29 Commits
.github/workflows		.github/workflows
docs		docs
reformat-cli		reformat-cli
reformat-core		reformat-core
reformat-plugins		reformat-plugins
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE		LICENSE
Makefile		Makefile
README.md		README.md
TODO.md		TODO.md

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reformat

Features

Modular transformers

Pipelines: presets and jobs

Quick processing (default command)

Library-first design

Observability

Installation

Library Usage

Case Conversion

Whitespace Cleaning

Combined Processing (Default Command)

Line Ending Normalization

Indentation Normalization

Regex Find-and-Replace

File Header Management

File Grouping

Quick Start

Default Command (Recommended)

Usage

Case Conversion

Whitespace Cleaning

Emoji Transformation

File Grouping

Broken Reference Detection

Line Ending Normalization

Indentation Normalization

Regex Find-and-Replace

File Header Management

Presets

Jobs

Logging and Debugging

Case Format Options

Examples

Case Conversion Examples

Whitespace Cleaning Examples

Emoji Transformation Examples

File Grouping Examples

Line Ending Normalization Examples

Indentation Normalization Examples

Regex Find-and-Replace Examples

File Header Examples

Preset Examples

License

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