lesster

What is lesster?

lesster is a Nim library that gives any terminal application a full-screen, keyboard-driven text viewer — the kind you already know from less or man — in just two lines of code.

It is built on top of nimwave and illwave, giving you smooth rendering, Unicode support, multiple colour themes, regex search, and optional Markdown highlighting, without any dependency on external system pagers.

Use it to display help text, log output, generated reports, or any long string your program produces — instead of dumping everything to stdout and losing the user in a wall of text.

Screenshot

Quick start

Add the package to your project:

nimble install lesster

Display an in-memory sequence of lines:

import lesster

let lines = readFile("report.txt").splitLines()
viewText(lines, title = "My Report", themeName = "default")

Or open a file directly (pass "-" for stdin):

import lesster

viewFile("output.log", title = "Build Log", themeName = "dark")

# pipe-friendly: cat report.txt | ./myapp -
viewFile("-", title = "stdin", themeName = "terminal")

Custom theme at runtime:

import lesster
from illwave as iw import nil

var myTheme = ThemesTable["dark"]
myTheme.titleBg = iw.bgBlue
myTheme.titleFg = iw.fgWhite
# See API reference for all Theme fields

Keyboard navigation

All bindings are active in the default normal mode. Press q at any time to exit.

Built-in themes

Pass a theme name to viewText / viewFile, or let users cycle through them interactively with Tab. You can also construct a Theme object from scratch for full control.

Ready to dig deeper?

The full API reference documents every exported symbol.