Special forms

Forms the evaluator treats specially, before function application. Their names are reserved in binding positions: binding if, quote, dotimes or any other name below is E-EVAL-005. Everything else, including every prelude macro and builtin, can be shadowed. A malformed special form is E-EVAL-005 with the expected shape.

Core

form	shape	page
`quote`	`(quote x)`, `'x`
`quasiquote`	`(a ,b ,@c)	macros
`if`	`(if test then [else])`; the chosen branch keeps multiple values	control
`progn`	`(progn form...)`
`let`	`(let ((name value)...) body...)`, initializers in the enclosing scope	functions
`let*`	`(let* ((name value)...) body...)`, each binding in a new scope	functions
`setq`	`(setq name value [name value]...)`, rebinds existing variables	functions
`lambda`	`(lambda lambda-list body...)`	functions
`flet`	`(flet ((name lambda-list body...)...) body...)`	functions
`labels`	the same, mutually recursive	functions
`macrolet`	`(macrolet ((name lambda-list body...)...) body...)`	macros
`dotimes`	`(dotimes (i count [result]) body...)`	control
`dolist`	`(dolist (item list [result]) body...)`	control
`multiple-value-bind`	`(multiple-value-bind (names...) expr body...)`	control
`multiple-value-list`	`(multiple-value-list expr)`	control
`multiple-value-call`	`(multiple-value-call f expr...)`	control
`multiple-value-prog1`	`(multiple-value-prog1 expr body...)`	control
`destructuring-bind`	`(destructuring-bind pattern list body...)`	functions
`macroexpand-1`, `macroexpand`	`(macroexpand form [env])`	macros
`intern`	`(intern string [env])`	macros

Definitions

form	shape	page
`defun`	`(defun name lambda-list body...)`	functions
`defmacro`	`(defmacro name macro-lambda-list body...)`	macros
`defvar`	`(defvar name value)`, once per module
`require`	`(require "module" name...)`, module top level only	require

Experiment

form	shape	page
`defmodel`	`(defmodel name lambda-list body... fn)`	models
`defparam`	`(defparam name initializer &key tags numerics)`, inside a model	models
`with-numerics`	`(with-numerics (:sensitivity :high) body...)`	numerics
`defoptimizer`	`(defoptimizer name (param grad ctx &key ...) body...)`	optimizers
`defstate`	`(defstate name zero-initializer)`, inside an optimizer	optimizers
`defknobs`	`(defknobs (name default ["doc"])...)`	knobs
`defvariant`	`(defvariant name (knob value)...)`	knobs
`defsweep`	`(defsweep name [:variant v] (knob [values])...)`	knobs
`defeval`	`(defeval name :loader l [:every n] [:batches k])`	evaluation
`defrun`	`(defrun :steps n ...)`	defrun

Definitions register when their form executes, so a macro can generate any of them; see generated declarations. The configuration constructors (loader, stage, files, manifest, field, select, group, named) are ordinary builtins; see builtins.