Scheme+ for Racket🔗ℹ

Damien MATTEI <Damien.MATTEI@univ-cotedazur.fr>

source code: https://github.com/damien-mattei/Scheme-PLUS-for-Racket

#reader SRFI-105

package: SRFI-105-for-Racket

This reader package provides the SRFI-105 Curly Infix reader/parser.

(require Scheme+)

package: Scheme-PLUS-for-Racket

This package provides the Scheme+ language definitions.

Scheme+ is an extension of the syntax of the Scheme language.

Scheme+ adds to Scheme a way to use also infix notation with a compatibility near 100% and not as a sub-system of Lisp syntax as it is often done but with a complete integration in the Scheme reader/parser system and also for Racket at REPL (Read Eval Print Loop).

Scheme+ is to Scheme what a concept-car is to automobile.Scheme+ is a concept-language.It is ideally what should be a modern Scheme.

Scheme+ makes it easy the assignment of Scheme objects in infix (works also in prefix) notation with a few new operators <- (or: ← , :=),⥆ (or <+) for definitions.

Scheme+ makes it easy the access and assignment for arrays,strings,hash tables,etc by allowing the classic square brackets [ ] of other languages.

1 Scheme+ Installation and Depandencies

2 Scheme+ Syntax and Conventions

1 Scheme+ Installation and Depandencies🔗ℹ

Scheme+ can be installed via the Racket Package system or downloaded from Github. Scheme+ is designed to be used with the package SRFI-105 for Racket which is a curly infix reader also available in the same way described above.

2 Scheme+ Syntax and Conventions🔗ℹ

In general Scheme+ use the same convention for infix expression than SRFI-105 Curly Infix that is an infix expression is between curly parenthesis { }. But infix sub-expressions are allowed to be between normal parenthesis ( ). Infix or prefix is then autodetected.In case of ambiguities { } force infix mode.

#reader SRFI-105 (require Scheme+) {3 * 5 + 2} 17

#lang reader SRFI-105
(require Scheme+)
{3 · 5 + 2 ³}
23

In the following sections i will omit to rewrite the directives about lang or reader and the requirement in each example to keep the code and the web page compact.

3 Scheme+ Reference🔗ℹ

3.1 Declarations🔗ℹ

syntax
(declare name1 name2 ...)

Declare new variables named name1,name2,....

Note: this is rarely used,instead assignment macros are used but could be usefull in case a variable used in a block must be used outside too.

3.2 Definitions🔗ℹ

syntax
{name <+ value}

Define new variable name and assign value value.

Note: this is almost never used in Racket,because Scheme+ for Racket as a special feature of autodetection if a variable needs to be defined before assignment.

There is some alias of this:

syntax
{name ⥆ value}

Note: a lot of operators of Scheme+ that works left to right exist in the opposite sense, i will not document them as it is obvious,example:

syntax
{value ⥅ name}

3.3 Assignments🔗ℹ

syntax
{name <- value}

Assign to the variable name the value value.

{x <- 7}
x
7

There is some alias of this:

syntax
{name := value}

{index := index + 1}

syntax
{name ← value}

{z ← 1.13+1.765i}

Example:

{M_i_o[j {i + 1}] <- M_i_o[j {i + 1}] + η · z_input[i] · მzⳆმz̃(z_output[j] z̃_output[j]) · ᐁ_i_o[j]}

DOCUMENTATION TO BE CONTINUED...

Another documentation is hosted on Github:

Documentation of Scheme+ for Racket on Github pages

1	Scheme+ Installation and Depandencies
2	Scheme+ Syntax and Conventions
3	Scheme+ Reference