frost, scratchpad

Chunk expressions, live.

Type an expression and see the result against the text on the left. it holds that text. This is the notation that replaces cut, awk, sed -n, head and tail with one grammar.

The text, edit it freely

Try these

This page evaluates expressions with web/chunks.js, a second implementation of the chunk grammar. tools/verify_chunks.py runs 1,288 expressions through both it and the real interpreter on every build, and the page is not written if they disagree. For the full language, run frost --try in a terminal.

The whole thing, actually running

The scratchpad above is a JavaScript reimplementation of chunk expressions. This is different: it is frost itself, the same Python the command line runs, compiled to WebAssembly. Every answer below is the answer you would get in a terminal.

It works because everything worth showing is static analysis. A manifest, a policy refusal and an approval are facts about the parse tree, and a parse tree needs no processes, no filesystem and no network. Only run needs a machine, which is the one thing a stranger's browser should not be doing.

Sample:

script

policy

Pick a sample and press a button.