README
¶
Example programs
Small programs that use Kukel for something real. Run them from this directory:
cd examples
kukel run grep.kkl -- -n -i error testdata/log.txt
| Program | What it does |
|---|---|
| grep.kkl | prints the lines of files (or of standard input) that match a regular expression (module re), with -i, -n, -v, -c, -l, -o, -F, -h, and -r for directories (module fs) |
| ninep.kkl | a 9P file server of a small tree the program makes up (a file that counts its readers, one that keeps notes written to it, a control file that stops the server) and, if given, a directory of the disk (read-only, as /files), and a client that lists, reads and writes files of 9P servers (module p9); demo does both in one process |
| notes.kkl | a small text editor in a window (module tk, so a kukel built with the tag tk): a File menu with New, Open, Save, Save as and Quit (also as Ctrl+N, Ctrl+O, Ctrl+S, Ctrl+Q), file dialogs, a question before changes are dropped, and a status line |
| todo.kkl | a task list kept in a database (module db with objects in tables, json, time): add (with a due date), done, rm, list by due date, export as JSON; each command a transaction; the commands come from the arguments or one per line from standard input, the database from -db (default sqlite:todo.db) |
| wc.kkl | counts the lines, words and bytes of files in parallel: -j N workers (module worker) each get the next file as they finish one (module events); a directory counts the files below it (module fs); -json prints the counts as JSON; the output is the same for any number of workers |
Kukel in a Go program
embed/ is a Go program that runs Kukel code (see
docs/embedding.md): it prices orders with discount
rules that users write as a Kukel script. The script gets a module of Go
functions (shop), and runs under the limits for code that is not trusted:
no files, no exit, only the modules json and strings, a step limit and a
time limit for each order. An error in the rules fails only that order.
go run ./examples/embed examples/embed/rules.kkl examples/embed/orders.json
go test ./examples/embed tests it, also with rules that go wrong.
Tests
notes.kkl shows a window instead of printing. The tests of the module
tk (make test-tk, with a display or Xvfb) run it, as they run the tk
examples of the reference: each must open its window and end without an
error when the window is closed.
Each other program has a file name.tests that go test ./cmd/kukel (and so
make test and make test-all) runs, in this directory:
# a comment
$ -n error testdata/log.txt
6:2026-10-16 09:05:00 error retrying write (attempt 2)
$ -x a
! grep: unknown option -x
! usage: grep [-icFhlnorv] pattern [file ...]
exit 2
A case starts with $ and the program's arguments: '...' quotes an
argument with spaces or backslashes, and < file gives the file as
standard input. The lines after it are the expected standard output, lines
starting with ! the expected standard error, and exit N the expected
exit code (0 when there is none). The files the programs read are in
testdata/. The programs are also kept formatted (kukel fmt -l lists
none).
Directories
¶
| Path | Synopsis |
|---|---|
|
Command embed is an example of a Go program that runs Kukel code (see docs/embedding.md): it prices orders, and the discount of each order comes from rules that users write as a Kukel script.
|
Command embed is an example of a Go program that runs Kukel code (see docs/embedding.md): it prices orders, and the discount of each order comes from rules that users write as a Kukel script. |