maueroats / super

Adds syntax to racket languages

super

Introduction

The super language is a meta-language that adds features to an existing racket language.

Use it as:

#lang super <lang>

where is the name of an language like racket, racket or similar.

Field and Method Access, Method Calls

In a super language identifiers with dots can be used for field access and for method calls.

1. o.f                       access field f of object o

2. o.f1.f2                   access field f2 of object o.f1

3. (o .m a ...)              invoke method m on object o wth arguments a...

4. (o .m1 a1 ... .m2 a2 ...) same as ((o .m1 a1 ...) .m2 a2 ...)

5. (o.m a ...)               invoke method m on object o wth arguments a... 

6. (o.m a ... .m1 a1 ...)    invoke method m1 on resultof object (o.m a ...) with arguments a2 ... 

See test-object-notation.rkt for an example.

Indexing with square brackets

In a super language the reader reads an expressions of the form

id[expr ...]      (no space between the identifier and the bracket)

as

(#%ref id expr ...).

A default binding for #%ref is provide that allows indexing for vectors, lists, strings and bytes.

The default bindings is defined like this:

(define-syntax (#%ref stx)
  (syntax-parse stx 
    [(#%ref x:id index:expr)
     (syntax/loc stx
       (let ([i index])
         (cond
           [(vector? x) (vector-ref x i)]
           [(list?   x) (list-ref   x i)]
           [(string? x) (string-ref x i)]
           [(bytes?  x) (bytes-ref  x i)]
           [else
            (error '#%ref (~a "expected a vector, list, string or byte string, got: " x))])))]))

See test-ref-expressions.rkt for an example.