convert-code

name	convert-code
description	Converts code between programming languages while preserving logic, error handling, and idiomatic patterns. Use when migrating modules between languages or frameworks.
argument-hint	[source file] to [target language]
allowed-tools	Read, Bash, Write, Grep

Code Conversion

Instructions

Step 1: Analyze Source Code

1. Read the source file completely
2. Identify:
   • All functions, classes, and types
   • External dependencies and their equivalents in the target language
   • Error handling patterns
   • Async/concurrent patterns
   • Data structures and their representations
   • Tests (if present)

Step 2: Map Language Idioms

Don't transliterate — convert to idiomatic target code:

Source Pattern	Target Equivalent
Python list comprehension	Java streams / Go slices / Rust iterators
JS Promise.all	Python asyncio.gather / Go goroutines+WaitGroup / Rust tokio::join
Python dict	Go map / Rust HashMap / Java Map
JS destructuring	Go multiple returns / Python tuple unpacking
Python decorator	Java annotation / Go middleware / Rust macro
C# LINQ	Python generators / JS array methods / Rust iterators
Ruby blocks	Python context managers / Go defer / Rust closures

Step 3: Handle Dependencies

For each import/dependency in the source:

1. Find the equivalent package/library in the target ecosystem
2. If no direct equivalent exists, note it and implement the functionality
3. Map API calls to the target library's conventions

Step 4: Convert Error Handling

Different languages handle errors differently:

Language	Pattern
Python	try/except, raise
JavaScript/TypeScript	try/catch, throw, Promise rejection
Go	Multiple return values (value, error)
Rust	Result<T, E>, Option, ? operator
Java/C#	try/catch, checked/unchecked exceptions
Ruby	begin/rescue/ensure
Elixir	{:ok, value} / {:error, reason} tuples

Convert error handling to the idiomatic pattern of the target language.

Step 5: Convert Types

Map type systems:

• Dynamic → Static: Infer and add explicit types
• Static → Dynamic: Simplify but add runtime checks where safety-critical
• Generics: Map to target language's generic system
• Null safety: Map Optional/Maybe/Option patterns appropriately

Step 6: Generate Output

1. Write the converted file with proper formatting
2. Add a header comment noting the source and conversion
3. Include all necessary imports
4. Preserve comments (translate them to the target language's convention)
5. Generate a companion test file if tests existed in the source

Step 7: Conversion Notes

Document:

• Patterns that couldn't be directly converted and the approach taken
• Dependencies that have no direct equivalent
• Behavioral differences to be aware of
• Performance characteristics that differ between implementations

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Rules

• Idiomatic over literal — code should look like it was written by a native developer
• Preserve behavior — the converted code must do the same thing
• Preserve tests — convert tests too, not just implementation
• Flag risks — note where behavior might differ (floating point, string encoding, concurrency)
• Don't assume — if unsure about a language feature, ask rather than guess