log

The log module provides leveled logging with filtering via an explicit Logger value (R8 W8 Cluster A 2026-05-24 — replaces the pre-R8 module-mutable global).

Import

from std::core::log use {
  logger, logger_at, set_level, get_level,
  LEVEL_TRACE, LEVEL_DEBUG, LEVEL_INFO, LEVEL_WARN, LEVEL_ERROR,
  trace, debug, info, warn
}

Note: error is also exported but shadows the comptime builtin error. Import it under an alias if needed, or call only the other levels at the top level.

Levels

From most to least verbose: LEVEL_TRACE (0), LEVEL_DEBUG (1), LEVEL_INFO (2), LEVEL_WARN (3), LEVEL_ERROR (4).

logger() defaults to LEVEL_DEBUG — all messages from debug up are shown.

Usage

let l = logger()                          // default = debug
info(l, "Server started")
warn(l, "Connection slow")
debug(l, "Request payload: " + payload)
trace(l, "Entering handler")

Set Level

Logger is immutable — set_level returns a fresh value with the updated minimum level.

let l = logger()
let l2 = set_level(l, LEVEL_INFO)   // hide trace and debug
debug(l2, "hidden")                  // not printed
info(l2, "visible")                  // [INFO] visible

For string-named levels, use level_num("info") then set_level(l, level_num("info")).

Functions

Function	Description
`logger()`	Construct a Logger at `LEVEL_DEBUG`
`logger_at(level: int)`	Construct a Logger at the given numeric level
`set_level(l: Logger, level: int) -> Logger`	Return a new Logger at the given level
`get_level(l: Logger) -> int`	Read the Logger’s current minimum level
`trace(l, msg)`	Log at trace level
`debug(l, msg)`	Log at debug level
`info(l, msg)`	Log at info level
`warn(l, msg)`	Log at warn level
`error(l, msg)`	Log at error level (import-rename to avoid comptime builtin shadow)
`level_num(name: string) -> int`	Map `"trace"/"debug"/"info"/"warn"/"error"` to its numeric level