Skip to main content

Writing Good Code in Flow-Wing

Style Conventions​

  • File extension: .fg
  • Indentation: 4 spaces
  • Variable names: camelCase
  • Type names: PascalCase
  • Function names: camelCase

Naming​

/; Good
var userName: str = "Alice"
type Point = { x: int, y: int }
class HttpClient {
  init() -> nthg {
  }
}

/; Avoid
var un: str = "Alice"
type point = { X: int, Y: int }

File Organization​

  • One module per file
  • bring imports at the top
  • Types and classes before functions
  • fg_main() at the bottom (or omit for simple scripts)

Error Handling​

Always check Err::Result return values:

bring file
bring Err

fun loadData() -> nthg {
  var content: str, werr: Err::Result = file::readText("data.txt")
  if (werr.isErr()) {
      println("Failed: " + werr.getMessage())
      return :
  }
  /; use content ...
}

loadData()

Debugging​

  • Use print() for quick inspection
  • Use io::printLog() for structured logging
  • Compile with --emit=ir to inspect generated LLVM IR
  • Run with make run-aot-debug FILE=your.fg for debug mode