Racket

A Sublime Text 4 plugin for the Racket programming language.

Supported extensions: .rkt, .rktl, .rktd (Racket syntax) and .scrbl (Scribble syntax: prose text with @-expressions, sharing every rule with the Racket syntax). .rkt files understand @-expressions anywhere in the file, matching #lang at-exp racket semantics.

Current features include:

• syntax definition and highlighting: every Racket form and literal is scoped
• build system: run, test, compile and format from command palette
• symbol indexing: Goto Symbol lists defined functions and structs
• comment settings: Toggle Comment uses ; and #| |#
• bracket handling: auto-indent after an open bracket, outdent on close
• REPL: Racket: Open REPL, Racket: Run File in REPL and Racket: Send Selection to REPL from command palette; send selection sends the current line when nothing is selected and starts a REPL if none is running (needs the Terminus package; set racket_executable in the Racket syntax settings if racket is not on PATH)

No completion or language-server integration is available. For those, use the LSP package with racket-langserver.

Installation

Via Package Control: Package Control: Install Package, then choose Racket.

Features

Syntax definition

The syntax is a .sublime-syntax written from scratch for the Sublime Text 4 engine.

• Complete generated identifier lists. All 413 special forms, 2135 procedures and 125 values exported by the racket module (v9.3) are recognised; the lists are produced by a script that queries Racket itself, so they can be regenerated for any future Racket version.
• Works with Sublime's editing features. Goto Symbol (Ctrl/Cmd+R) lists every defined function and struct in the file. Toggle Comment (Ctrl/Cmd+/) inserts ; and block comment inserts #| |#. Pressing Enter after an open bracket indents; typing a close bracket outdents. Double-clicking string->list selects the whole identifier, not string alone, and ? or ! at the end of a name is part of the word.
• Scopes depend on position, not just on the word. The operator of a form is scoped as a special form (define, let), a builtin procedure (map), an operator (+), or a user function call (my-fn), while the same identifier used as an argument is scoped as a value. Binding sites are distinguished too: the name in (define (add x y) …) is a definition and x, y are parameters; x in (let ([x 1]) …) is a binding; point, x, y in (struct point (x y)) are a type name and fields.
• Every kind of literal Racket can read is recognised. Comments in all three forms: ; line, #| block |# (which may nest), and #; followed by one expression, which comments out exactly that expression, however many lines it spans. Strings of every flavour: "plain", #"bytes", #rx"regexp", #px"regexp", and #<<EOF here-strings. Characters like #\a, #\space, #\x41. Keywords like #:name. Numbers with prefixes such as #x1F, #b101, #e1.5, fractions 1/3, and +inf.0. Quote marks ', `, ,, ,@, #', #,. Vector and hash literals #(1 2), #hash((a . 1)).

Known limitations can be found in the dev docs.

Build system

A build system is included (Tools > Build With...):

• Run (racket): runs the current file and shows its output
• Test and Test Directory (raco test): runs test submodules and rackunit tests in the current file, or in every file under its directory
• Compile (raco make): compiles to bytecode without running, so it reports syntax and unbound-identifier errors quickly
• Format (raco fmt -i, needs raco pkg install fmt): reformats the current file in place
• Expand (raco expand): prints the fully macro-expanded program, useful for seeing what a macro produces
• Check Requires (raco check-requires): reports required modules that are unused or could be narrowed

Error locations in the output panel are clickable. racket and raco must be on the PATH Sublime sees; on macOS that is the login shell's PATH when launched from the Dock.