(Lispex)

See it run

LISPEX

((lambda (x) (if #t x 0)) 42)

Observed result

OUTPUT

if has a mandatory else arm, and begin and procedure bodies preserve left-to-right order.
lambda supports fixed and dotted formals. set! mutates an existing cell, and define updates or creates a top-level cell.
quote returns immutable literal data, and the runtime does not evaluate quoted elements.
module is written (module name (export id ...) (import name ...) body ...) and may only sit at top level. Nest it inside another form and you get E130. The export and import clauses come before the body.
A module header is checked and then discarded, and the body is flattened outward. It does not create a namespace. Do not expect it to hide anything. That is why (f 21) below is called from outside the module.

LISPEX

(module doubling
  (export twice)
  (define (twice x) (* x 2)))

(twice 21)

Observed result

OUTPUT

Form	Arguments / evaluation	Result or fault
quote	1 datum, no element evaluation	immutable datum
if	test, consequent, alternate, with the test first	the values from the selected branch. E320 if the test is not one value
lambda	formals plus 1..N body forms	closure. E302 when applied with the wrong number of arguments
set!	a name and a single-value expression on the right	zero values. E303 if the name is unbound
let / letrec	binding list plus 1..N body forms	the values from the last body form. E321 on an uninitialized letrec read
module	a name, 0..2 header clauses, 1..N body forms	the body, flattened outward. E130 anywhere but top level

Convenience forms written as shorthand belong to the derived-form reference.

Derived Forms holds the shorthand that normalizes into these shapes, and the manual explains when each subexpression runs.