Builtins

Every builtin function, evaluated at compile time. Tensor operations are in tensor operations; prelude macros and functions written in Lisp are in the prelude. Builtins need no require and can be shadowed.

Arithmetic and comparison

names	notes
`+` `-` `*` `/`	n-ary; `/` always returns a float, so `(/ 1 2)` is `0.5` and a head dimension is `(floor (/ dim heads))`
`mod` `pow` `sqrt` `exp` `log` `floor`	`floor` returns an integer
`min`	numbers only
`max`	numbers, or the maximum of a tensor
`=` `/=` `<` `<=` `>` `>=`	numeric; `/=` requires pairwise distinct arguments
`eq` `equal`	identity, and structural equality for data; use `equal` for lists, strings, keywords
`not` `truthy`	`(truthy x)` is `true` unless `x` is `nil` or `false`

+ - * / pow sqrt exp log max and the six comparisons are overloaded: the tensor reading wins when any argument is a tensor. Integer overflow and division by zero are E-EVAL-007.

Lists and higher order

builtin	result
`(list x...)`	a list
`(cons x list)`	a new list with `x` in front; there are no dotted pairs
`(first xs)` `(rest xs)`	the first element or `nil`, and the rest as a list
`(nth i xs)`	the `i`-th element, `nil` past the end
`(length xs)`	elements of a list or vector, characters of a string
`(append xs...)`	one list
`(reverse xs)`	a list
`(vector x...)`	a vector; `[x ...]` is the literal
`(vec xs)` `(to-list xs)`	a vector from a list, a list from a vector
`(map f xs)`	a list of `(f x)`; one sequence only
`(filter f xs)`	the elements where `(f x)` is true
`(reduce f init xs)`	a left fold, `(f (f init x0) x1)`...
`(repeat n f)`	`(list (f 0) ... (f (- n 1)))`
`(range n)` `(range a b)`	integers from 0 or `a` below `n` or `b`
`(apply f arg... list)`	see functions

Sequence builtins accept a list or a vector and return a list. nil is the empty list. Lists are immutable.

Plists

builtin	result
`(plist :k v ...)`	a property list; keys must be keywords and come in pairs
`(getf plist key [default])`	the value after the first `equal` key, else `default` or `nil`

ctx, prepare's return value and curriculum observations are plists.

Multiple values

values and values-list; the binding forms are special forms, see multiple values.

Text and symbols

builtin	result
`(str x...)`	the printed forms concatenated into one string
`(format "~a~%" x...)`	a string; understands `~a` and `~%` only
`(symbol-name s)`	the printable name of a symbol or keyword, a string
`(keyword x)`	a keyword from a symbol, string or keyword
`(gensym [prefix])`	a fresh symbol; see macros
`(symbol-prefix-p "g!" s)`	whether a symbol's name starts with the prefix

intern is a special form; see macros.

Predicates

consp (a non-empty list), listp (a list or nil), vectorp, null, numberp, keywordp, symbolp, stringp, and functionp (a function, builtin, model, model constructor or optimizer definition).

Errors

(error message...) is E-EVAL-001; (assert test [message]) is E-EVAL-002. See control.

Experiment constructors

Ordinary builtins that build configuration values:

builtin	page
`loader` `stage` `files` `manifest` `field`	loaders
`select` `select-not` `select-and` `group`	optimizer groups
`named`	models
`optimizer-update`	writing optimizers
`metric` `diagnostic` `tap-gradient` `counter`	metrics, writing diagnostics, loaders

field also reads a batch inside prepare: (field batch :tokens).