ic

IceCream-style debug printing for Nim. A debugging library inspired by Python's icecream that provides colored, informative debug output with variable names, values, timestamps, and source locations.

Features

• Colored output - Green, red, blue, and yellow variants for visual differentiation
• Zero-cost when disabled - All macros compile to nothing when not enabled
• Cross-platform - Native, JavaScript, and NimScript support
• Configurable - Control what information appears in output via compile-time defines
• Multiple arguments - Print several variables in one call

Installation

nimble install ic

Quick Start

import ic

let x = 42
let name = "hello"

ic x           # Green output
icr name       # Red output
icb x, name    # Blue output (multiple args)
icy x + 1      # Yellow output (expressions work too)

Compile with -d:ic to see output:

nim c -r -d:ic myfile.nim

Output:

1736812345 | /path/to/myfile.nim:5 | 'x' | 42
1736812345 | /path/to/myfile.nim:6 | 'name' | hello
1736812345 | /path/to/myfile.nim:7 | 'x' | 42
1736812345 | /path/to/myfile.nim:7 | 'name' | hello
1736812345 | /path/to/myfile.nim:8 | 'x + 1' | 43

Macros

Configuration

All configuration is done via compile-time defines:

Examples

Enable everything with human-readable timestamps:

nim c -r -d:ic -d:ic.hrdt=true myfile.nim

Minimal output (value only):

nim c -r -d:ic -d:ic.show_time=false -d:ic.show_location=false -d:ic.show_variable=false myfile.nim

Add a prefix for filtering logs:

nim c -r -d:ic -d:ic.prefix=DEBUG myfile.nim

Enable only red and yellow for errors/warnings:

nim c -r -d:icr -d:icy myfile.nim

Platform Support

Native (default)

Full color support via std/terminal. All features available.

JavaScript (-d:js)

Maps to browser console methods: - ic → console.trace - icr → console.error - icb → console.info - icy → console.warn

Also provides group templates for console grouping:

group "My Group":
  ic someValue
  icb anotherValue

NimScript

Basic echo-based output with location info. Works in .nims files and nimble tasks.

Checkpoints

For simple checkpoint-style debugging, use the blok template:

import ic

blok "processing data":
  # your code here
  discard

# or use the cp()

let p = foo()

cp() # A checkpoint

let v = bar()

Compile with -d:cp to enable checkpoint output.

Tips

• Use different colors to categorize your debug output (e.g., icr for errors, icy for warnings)
• The macros accept expressions, not just variables: ic myList.len, ic a + b * c
• Remove -d:ic from production builds for zero overhead
• Use -d:ic.prefix to tag output from specific modules

License

MIT