A self-contained Zed language extension for ANS-style Forth and OpenOS Forth.
The extension provides syntax highlighting, outline support, indentation, comments, text objects and snippets without requiring an LSP.
Open Zed and run zed: install dev extension, selecting this directory.
.fs,.fth,.4th,.frt,.blkdetection- Tree-sitter highlighting and lexical structure
\line comments and parenthesized( ... )comments- structured stack effects such as
( addr len -- buf n ) - stack-effect parameter highlighting distinct from comment text
: name ... ;definitions in Outline- variables, constants and other defining words in Outline
- indentation and structural
:/;matching - comment text objects
- ANS-style Forth words, operators and control flow
- snippet-based completion without an LSP
- OpenOS Forth words including
depth,getpid,argc,arg,s>number,load-file,save-file,peek,poke,call,hex,,data-base,ms,bye,<=, and>= $HEX,0xHEX,%binary,&octal, decimal and floating-point numbers- standard Forth string forms, including dot-quote, s-quote, c-quote, and abort-quote
examples/openos/ contains small OpenOS Forth examples used to verify highlighting and parsing of definitions, variables, stack effects, control flow, strings, arithmetic, file/process words and MMIO-style words.
./verify.shThe check validates JSON/TOML files, Tree-sitter query node names, the bundled parser, regression examples and the publication manifest.
If the tree-sitter CLI is installed, the verification script also runs the corpus tests.
Forth can extend its dictionary and compilation semantics at run time, so the grammar keeps the general language structure intentionally lightweight.
Stack effects are parsed more precisely because they have stable documentation syntax. Expressions such as ( addr len -- buf n ) expose delimiters, parameter text and the -- separator separately, allowing Zed to style stack-effect parameters independently from ordinary comments.