toggle

A Rust-based CLI and library for toggling, adding, removing, and updating code/comments across multiple languages, featuring flexible extension mappings and full configurability via file or command-line.

Below is a structured technical requirements document for a command-line tool called toggle. This tool enables toggling comment blocks in one or more files. The focus is on Rust implementation details, supported comment styles, and multi-file toggling. Each section is designed to capture your requirements in a clear, concise format.

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1. Overview

Goal
Create a Rust-based CLI tool, toggle, that can:

• Comment or uncomment designated lines or blocks of text in code files.
• Detect and apply correct single-line or multi-line comment styles by file extension.
• Work off a configuration file (.toggleConfig) or command-line arguments.
• Identify labeled "sections" to toggle on or off across multiple files.
• Provide granular control (line-based, section-based, file-based, multi-file).

Core Objectives

1. Line-based toggling: Support start/end line numbers, or a start line with a fixed number of lines, or a start line to the end of the file.
2. Section-based toggling: Recognize in-file sections tagged with an ID (e.g., SECTION_ID=foo) and toggle all occurrences (on/off) across a codebase.
3. Configurable comment styles: Auto-detect comment style by file extension or override with custom settings.
4. Extendable: Allow a .toggleConfig file to hold global or per-language comment preferences.

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2. Command-Line Interface (CLI)

2.1 Basic Command Syntax

toggle [OPTIONS] <file_or_directory_paths>...

2.2 Primary Flags & Arguments

Flag / Arg	Description	Example
-l, --line (repeatable)	Specify line-based toggles in the format <start_line>:<end_line> or <start_line>:+<count>.	--line 10:20 or --line 15:+5
-S, --section (repeatable)	Specify section ID(s) to toggle.	--section featureXYZ
-f, --force [on|off]	Force a toggle state for line-based or section-based operations.	--force on
-m, --mode [auto|single|multi]	Defines the comment mode. auto will use file extension to determine the style, single/multi overrides.	--mode single
-c, --comment-style	Manually specify exact delimiters for single/multi-line comments (overrides auto detection).	--comment-style "//" "/*" "*/"
--to-end	If set, toggling continues from <start_line> to the end of the file.	--line 50 --to-end
--config <path>	Points to a custom .toggleConfig file. Default is .toggleConfig in current directory if present.	--config /path/to/altConfig
-R, --recursive	Recursively search directories for files that match the toggled sections or line references.	-R src/
-v, --verbose	Show detailed logs (lines changed, files modified, etc.).	--verbose
--dry-run	Show which changes would be made, without altering files.	--dry-run --verbose

2.3 Behavior Examples

1. Line Range Toggle

   toggle --line 10:20 main.py

   • Auto-detects .py → uses # for single-line comments.
   • Comments out lines 10 to 20 (or toggles them if already commented).

2. Line Range to End

   toggle --line 30 --to-end MyClass.java

   • Auto-detects .java → uses // or /*...*/.
   • Comments out from line 30 to EOF.

3. Section-Based Toggle

   toggle --section signupFlow --force on src/

   • Recursively scans src/ to find any sections labeled signupFlow.
   • Forces them all to become commented (on).

4. Override Comment Style

   toggle --mode multi --comment-style "//" "/*" "*/" --line 40:45 test.cc

   • Forces multi-line mode but uses custom single-line prefix // if needed.
   • The multi-line delimiters are explicitly /* and */.

5. Multiple Toggles in One Command

   toggle --line 10:20 --section adminUI --force off module.ts

   • Toggles lines 10–20 and a named section adminUI in module.ts.
   • Forces off any commented region that is identified by adminUI.

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3. Configuration File (.toggleConfig)

3.1 Purpose

• Defines default behavior per file extension or globally.
• Acts as the fallback if command-line arguments are not specified.

3.2 Format

[global]
default_mode = "auto"
force_state = "none"  # valid: on, off, none (i.e., invert if toggling)
single_line_delimiter = "//"  
multi_line_delimiter_start = "/*"
multi_line_delimiter_end = "*/"

[language.python]
single_line_delimiter = "#"
multi_line_delimiter_start = "\"\"\""
multi_line_delimiter_end = "\"\"\""

[language.ruby]
single_line_delimiter = "#"

[language.java]
single_line_delimiter = "//"
multi_line_delimiter_start = "/*"
multi_line_delimiter_end = "*/"

Notes:

• global section sets the baseline.
• Each [language.xxx] overrides settings for .xxx files.
• If no extension is recognized, the program either throws an error or uses global defaults.

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4. Section Markers in Source Files

4.1 Marker Convention

A standard marker might look like this (example for Java/JS/C-style):

// toggle:start ID=featureX desc="Enable the new feature"
  System.out.println("New feature code here...");
// toggle:end ID=featureX

Or for Python:

# toggle:start ID=featureX desc="Enable the new feature"
print("New feature code here...")
# toggle:end ID=featureX

Proposed Format:

[toggle:start ID=<identifier> desc="<description>"]
...
[toggle:end ID=<identifier>]

• ID is mandatory.
• desc is optional.
• The line format must be recognizable by toggle. For example:
  • // toggle:start ID=featureX desc="..."
  • # toggle:start ID=featureX desc="..."
  • /* toggle:start ID=featureX desc="..." */ (depending on language)

4.2 Behavior

• Toggling ON: If the block is not commented, comment it out. If already commented, do nothing.
• Toggling OFF: If the block is commented, uncomment it. If already uncommented, do nothing.
• No Force: If neither --force on nor --force off is set, toggle inverts the current state.
• Global Toggle: The tool can scan multiple files (via -R or listing files) and apply toggles to all occurrences of an ID.

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5. Implementation Outline (Rust)

1. Argument Parsing

   • Use a crate like Clap or StructOpt for robust CLI handling.
   • Collect line toggles (Vec<String> for <start_line>:<end_line>, etc.), sections, force states, and mode overrides.

2. Configuration Handling

   • On startup, attempt to load .toggleConfig (or alternative path if --config is specified).
   • Parse with a TOML library (e.g., toml).
   • Merge config values with command-line overrides.

3. File Scanner

   • If user inputs directories and -R is set, recursively walk the directory using walkdir.
   • Filter files by extension or by presence of toggle markers.

4. Comment Style Determination

   • If --mode auto, map extension → comment style. If not found, throw an error.
   • If --comment-style ... is passed, override the style.
   • If .toggleConfig contains [language.xyz] that matches extension, use those defaults unless overridden.

5. Parsing the File

   • For each file, read line by line into a buffer (e.g., Vec<String>).
   • For line-based toggles:
     • Identify the relevant range(s).
     • Comment or uncomment accordingly.
   • For section-based toggles:
     • Detect lines that match toggle:start ID=... and toggle:end ID=....
     • Determine if the block is currently commented or not.
     • Apply on/off or invert logic.

6. Commenting / Uncommenting Logic

   • Single-line approach (e.g., #, //): Prepend or remove the token from each line.
   • Multi-line approach (e.g., /* ... */):
     • Insert /* at the first line, */ at the last line (or for partial lines, handle carefully).
     • Alternatively, comment each line singly if that's simpler for toggling.
   • Keep track of lines that are already partially or fully commented to avoid double-commenting.

7. Output & Write-Back

   • After toggling, write the modified buffer back to the file (unless --dry-run is set).
   • If --dry-run, print a summary of changes.

8. Edge Cases

   • Overlapping toggles for the same lines or sections.
   • Nested sections (some languages permit nested comment blocks).
   • Files with unusual line endings (CRLF vs. LF).
   • Extremely large files (consider streaming vs. loading entire file).

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6. Example Use Case Scenarios

Scenario A: Toggling a Feature in Multiple Files

toggle --section featureX --force off -R src/

• Recursively looks for toggle:start ID=featureX/toggle:end ID=featureX.
• Forces it off. If some blocks were on, they get uncommented.

Scenario B: Automated Build Script

• Integrate toggle in a CI script to enable certain code blocks for a staging environment:

  toggle --section stagingFeature --force on path/to/config.yaml path/to/server.java

• Re-run with --force off after tests complete.

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7. Error Handling & Logging

1. Unknown Extension

   • If --mode auto and the file extension has no known mapping, error: “Cannot detect comment style for ‘.xyz’. Use --mode or .toggleConfig to specify.”

2. Conflicting Options

   • If --mode single and --comment-style multi-line tokens are provided, prefer the explicit --comment-style or show a warning and proceed with single-line prepends.

3. Invalid Ranges

   • If start_line > end_line, skip or warn.
   • If lines exceed file length, skip out-of-bound lines and log a warning.

4. Section Mismatch

   • If toggle:start ID=foo is found but no matching toggle:end ID=foo, log a warning: “Unclosed section ID=foo in filename.”

5. Verbose Logging

   • If -v, --verbose, show each line range or section ID processed and the new state.