[dependencies]
chart = "^0.1.1"

chart

Draw charts in your terminal, straight from a stream of numbers. chart is both an installable CLI and a reusable NURL library — pure NURL, no FFI, leak-clean under AddressSanitizer/LeakSanitizer.

seq 1 20 | chart spark
▁▁▂▂▂▃▃▄▄▄▅▅▅▆▆▇▇▇██

printf '%s\n' 'apples 8.5' 'pears 6' 'cherries 2.1' | chart bar
apples   ██████████████████████████████▉ 8.5
pears    █████████████████████▉ 6
cherries ███████▋ 2.1

It lives in the NURL registry, not the core stdlib: charting is opinionated (which glyphs, which scaling, which layout) in a way the language proper should stay out of, but it is exactly the everyday utility an ecosystem exists to provide. It parses flags with the stdlib std/args and leans on the shipped stdlib for everything else.

Install

nurlpkg install chart

CLI

chart <spark|bar|hist|line> [options]

Mode	What it draws
spark	a one-line sparkline (▁▂▃▄▅▆▇█) of the numbers
bar	labelled horizontal bars, one input line per bar
hist	a histogram — bins the numbers and draws the counts
line	a line/scatter plot on a character grid (plot is an alias)

Input is whitespace-separated numbers read from stdin (or --file). Non-numeric tokens are ignored. In bar mode each line is one bar: <label…> <value> (the last token is the value, the rest the label), or a bare number whose label is its 1-based position.

Options

Flag	Applies to	Meaning
-w, --width N	bar/hist/line	chart width in cells (default 40)
--height N	line	plot height in rows (default 10)
-b, --bins N	hist	number of buckets (default 10)
-f, --file PATH	all	read numbers from PATH not stdin
-t, --title T	all	print T on a line above the chart
-h, --help		show help

Examples

# CPU load at a glance
uptime | grep -o '[0-9.]*' | tail -3 | chart spark

# distribution of file sizes
ls -l | awk '{print $5}' | chart hist --bins 8 -w 30

# a quick line plot from a file
chart line -f temps.txt --height 12 -t "Temperature"

# bars with multi-word labels
printf '%s\n' 'New York 19' 'Los Angeles 13' 'Chicago 27' | chart bar

The bars use Unicode block elements at eighth-cell resolution, so a value of 3.5 cells reads as three full blocks plus a half block (███▌) rather than rounding to whole characters. The line plot maps the series onto a grid (top = max, bottom = min), resampling to the requested width and joining consecutive samples so it reads as a connected line; it handles negatives.

Library

Add the dependency and import the renderer:

[dependencies]
chart = "^0.1"

$ `deps/chart/src/chart.nu`

: ( Vec f ) v ( vec_new [f] )
( vec_push [f] v 3.0 ) ( vec_push [f] v 7.0 ) ( vec_push [f] v 5.0 )
: String s ( chart_sparkline v )      // ▃█▆  (caller frees with string_free)

API

Every renderer returns an owned String; free it with string_free. values is a ( Vec f ); labels is a ( Vec String ) that is borrowed (never freed or retained). Widths/heights are in terminal cells.

( chart_sparkline values )           → String   one-line ▁▂▃▄▅▆▇█
( chart_bars labels values width )   → String   labelled horizontal bars
( chart_hist values bins width )     → String   binned histogram
( chart_plot values width height )   → String   line/scatter grid

( chart_min  values )                → f        summary statistics
( chart_max  values )                → f
( chart_sum  values )                → f
( chart_mean values )                → f

Bars and histograms assume non-negative values (the natural shape for a bar chart); a negative value draws an empty bar. The plot accepts any range. An empty series yields an empty string rather than trapping.

Build & test locally

From the package directory, with the in-tree toolchain:

NURL_STDLIB=/path/to/nurl-lang \
  /path/to/nurl-lang/nurl.sh src/main.nu chart   # build the CLI
echo 1 2 3 4 5 | ./chart spark

License

MIT OR Apache-2.0.