4 Shrubbery Language🔗ℹ

The shrubbery meta-language is similar to the s-exp meta-language. It expects a module name after #lang shrubbery to serve as the language of a Racket module form, while the body of the module after the #lang line is parsed as shrubbery notation.

Unlike s-exp, shrubbery also works without another language listed on the #lang line. In that case, running the module prints the S-expression form of the parsed shrubbery (see Parsed Representation). For example,

#lang shrubbery

1+2

prints '(multi (group 1 (op +) 2)). But if "demo.rkt" contains

"demo.rkt"

#lang racket/base

(require (for-syntax racket/base

syntax/parse))

(provide (rename-out [module-begin #%module-begin])

+ - * /)

(define-syntax (module-begin stx)

(syntax-parse stx

#:datum-literals (multi group op)

[(_ (multi (group n1:number (op o) n2:number)))

#'(#%module-begin (o 'n1 'n2))]))

then

#lang shrubbery "demo.rkt"

1+2

prints the result 3.

A same-line module language for shrubbery is determined by using parse-all in 'line mode. As long as the resulting shrubbery is not empty, it is parsed in the same way that rhombus parses module names for import.

The shrubbery/text meta-language is similar to shrubbery, but it parses the module in 'text mode. For example,

#lang shrubbery/text

@(1+2)

prints '(brackets (group (parens (group 1 (op +) 2)))).