As I mentioned in class, the presence of macros in the lisp family of languages

Question

As I mentioned in class, the presence of macros in the lisp family of languages has led to many subtly-different implementations of the same concept. Just as function definition isn't a fundamental operation (it is composed of definition and lambda), the let mechanism can be constructed from lambdaalone. The Clojure code

(let [x 10, y 20] (* x y))

is equivalent to

((fn [x y] (+ x y)) 10 20). Thus, many different implementations exist (In fact, some of the differences in let forms have been cited in the renaming of PLT Scheme to Racket (https://racket-lang.org/new-name.html)

Let's help make schemers more at home in Clojure with a macro that allows scheme-style macros to be used.

Rather than try to support both syntaxes from a single macro, you'll define a new one such that

(let-scm ((x 10) (y 20)) (+ x y))

is the same thing as

(let [x 10 y 20] (+ x y))

Explanation / Answer

Macros

Macros allows to redefine the synxtax, create new language constructs, expand the language and create DSL - Domain Specific Languages.

Note: all the macros bellow were tested on GNU GUILE that was started with the command:

increment a variable

>

Swap two variables

Convert Infix Operator to prefix operator

Invert Predicate

scm ((x 10) (y 20)) (+ x y)) is same thing as ([x 10 y 20] (+ x y))

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