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<!DOCTYPE html><html lang="en">
<head>
<meta charset="utf-8">
<meta name="description" content="Language Reference for Murmel, a Lisp dialect.">
<meta name="keywords" content="murmel, murmel-lang, lisp, lisp-dialect">
<title>Murmel Language Reference</title>
<script>window.texme = { useMathJax: false, protectMath: false }</script>
<script src="https://cdn.jsdelivr.net/npm/texme@1.2.2"></script>
</head>
<textarea>
# Murmel Language Reference
The file `murmel-langref.lisp`
is an executable language reference manual
for Murmel, a single-namespace Lisp dialect
inspired by Common Lisp.
See also Murmel's default library [Mlib](mlib.html)
which contains additional functions and macros.
The file `murmel-langref.lisp` can be read as-is or run with:
$ java -jar jmurmel.jar --repl --echo < murmel-langref.lisp
or transformed to Markdown:
$ sed -nf scripts/langref-to-md.sed murmel-langref.lisp \
> murmel-langref.md
Murmel is WIP, please note the section
[Known issues](#known-issues) at the end of this file.
## Murmel Reference
- [S-expressions](#s-expressions)
- [Comments](#comments)
- [Predefined Symbols](#predefined-symbols)
- [Basic Special Forms](#basic-special-forms)
- [Function application](#function-application)
- [Data types](#data-types)
- [Reserved words](#reserved-words)
- [Variables and scope](#variables-and-scope)
- [Additional Special Forms](#additional-special-forms)
- [Backquote - fill-in templates](#backquote)
- [Basic Primitives](#basic-primitives)
- [Logic, Predicates](#logic-predicates)
- [Conses and lists](#conses-and-lists)
- [Vectors, Sequences](#vectors-sequences)
- [Hashtables](#hash-tables)
- [I/O](#io)
- [Misc](#misc)
- [Time](#time)
- [Predefined Numeric Primitives](#predefined-numeric-primitives)
- [Predefined Graphics Primitives](#predefined-graphics-primitives)
- [Java FFI](#java-ffi)
Additional functions that can be loaded with `(require "mlib")`
- [Mlib - Default library for Murmel](mlib.html)
## Introduction
"Hello, World!" program written in Murmel:
(jformat t "Hello, World!")
The program text above when run in the REPL should print the famous
Hello, World!
followed by the result of `jformat`
==> nil
and the prompt `JMurmel>`.
## S-expressions
Murmel is a Lisp dialect. As such the language isn't
really defined in terms of program text but in terms
of in-memory objects (lists, symbols and other atoms)
that are acceptable to `eval`.
That said, JMurmel's default reader turns S-expressions
from the input stream into equivalent in-memory objects. So
for this reference we'll use S-expressions to describe
programs that are valid Murmel, i.e. are acceptable to `eval`.
In this reference in-memory objects that are valid Murmel
(as well as their textual representation as S-expressions)
are referred to as "forms".
The following are S-expressions that JMurmel's reader
will accept and transform into in-memory objects.
Valid S-expressions may or may not be "forms"
(i.e. may or may not eval w/o error).
### Atoms that are not symbols
1
1.0
"a string"
#\a ; the character 'a'
#xff ; the integer number 255 in hex
### Single quote
A single quote `'` is a shorthand for `(quote form)`,
see [Basic special forms](#basic-special-forms).
'form
### Atoms that are symbols
Symbols usually start with a letter and are composed of
letters, digits and dashes ('-'),
but pretty much any token that is not another atom will be
parsed as a symbol.
Murmel handles symbols similar to Common Lisp,
see "CLHS 2.3.4 Symbols as Tokens" http://clhs.lisp.se/Body/02_cd.htm
for details.
Examples:
'a-symbol
'|a symbol|
'a\ symbol
'123"345
'123.456.789
### Conses (pairs) and lists
A dotted pair
'(a . b) ; ==> (a . b)
A dotted list
'(a . (b . (c . d)))
Shorthand for dotted list
'(a b c . d)
A proper list
'(a . (b . (c . ()))) ; ==> (a b c)
Shorthand for a proper list
'(a b c) ; ==> (a b c)
### Labeled subobjects
Since: 1.4.6
'(a #1=b #1# c) ; ==> (a b b c)
Note that a label can only be used after it's value was completely read,
i.e. `'#1=(a b . #1#) is an error in Murmel (while valid in CL).
### Hashtables
Since: 1.3.1
#H(eql k1 v1 k2 v2 k3 v3)
## Comments
One line comments are started with `;`, i.e. everything between a semicolon
and the end of the line is ignored:
; this is a comment
Multiline comments are started with `#|` and ended with `|#`:
#|
This is a
multiline comment.
|#
The pair `#!` and `!#` can also be used for multiline comments.
## Predefined Symbols
### `nil` and `t`
`nil` and `t` are pre-defined self-evaluating symbols.
nil ; ==> nil
t ; ==> t
Murmel treats the symbols `nil` and `t` the same way
as Mr. Moon specified them in a Memo (see "The Evolution
of Lisp pp 62"):
> NIL is a symbol, the empty list, and the distinguished
> "false" value. SYMBOLP, ATOM, and LISTP are true of it;
> CONSP is not. CAR, CDR, and EVAL of NIL are NIL.
> NIL may not be used as a function, nor as a variable.
>
> T is a symbol and the default "true" value used by predicates that
> are not semi-predicates (i.e., that don’t return "meaningful" values
> when they are true.) EVAL of T is T. T may not be used as a variable.
> T is a keyword recognized by certain functions, such as JFORMAT.
### internal-time-units-per-second
`internal-time-units-per-second` contains the resolution
of the time related functions, see below.
internal-time-units-per-second ; ==> 1.0E9
### pi
`pi` contains the value of the mathematical constant pi
in double precision.
pi ; ==> 3.141592653589793
### \*command-line-argument-list\*
`*command-line-argument-list*` contains all command line arguments
to the Murmel program. Below example illustrates this:
C:\> java -jar jmurmel.jar -- a b c
...
JMurmel> *command-line-argument-list*
==> ("a" "b" "c")
JMurmel>
### array-dimension-limit
Largest acceptable vector index.
### most-positive-fixnum, most-negative-fixnum
These global variables contain the smallest and largest fixnum value.
### \*condition-handler\*
Since: 1.4
This variable can be set to a function of one parameter.
If `*condition-handler*` is non-nil then it will be invoked in case of an error,
the argument will be the condition describing the error.
During invocation of the condition handler it will be disabled:
if the current handler dynamically replaced a previous handler
then the previous handler will be temporarily restored.
### \*random-state\*
Since: 1.4.4
Will initially be `nil`. Will be lazily created by one-arg `random`
or zero-arg `make-random-state`.
### REPL variables
@-, @+, @++, @+++, @\*, @\*\*, @\*\*\*, @/, @//, @///
These variables are only defined when using the REPL.
They work similar to CL's REPL variables without the leading `@`.
The global variables @\*, @\*\*, @\*\*\* are maintained by the Lisp read-eval-print loop
to save the values of results that are printed each time through the loop.
The value of @\* is the most recent primary value that was printed,
the value of @\*\* is the previous value of @\*,
and the value of @\*\*\* is the previous value of @\*\*.
If several values are produced, @\* contains the first value only;
@\* contains nil if zero values are produced.
The values of @\*, @\*\*, and @\*\*\* are updated immediately prior to printing the return value
of a top-level form by the Lisp read-eval-print loop.
If the evaluation of such a form is aborted prior to its normal return,
the values of @\*, @\*\*, and @\*\*\* are not updated.
## Basic Special Forms
### quote
(quote form) -> form
`quote` returns a form without evaluating it.
(quote a-symbol) ; ==> a-symbol
### lambda
(lambda (params*) forms*) -> closure
When a lambda is created by the special form `lambda`
then the lexical environment is captured at the time of lambda creation.
Arguments to the special form `lambda` are not evaluated.
(lambda (p1 p2) p1)
`lambda` with varargs:
If paramlist is a symbol then all arguments will be
packed into a list and bound to the symbol.
If paramlist is a dotted list then remaining arguments
will be bound to the last parameter.
(lambda popt (write popt)) ; no mandatory arguments
(lambda (p1 p2 . prest) (write prest)) ; two mandatory arguments
## Data types
Murmel supports symbols and cons cells (and lists built from cons cells)
as well as other atoms that are not symbols.
These other atoms are double precision floating point numbers,
integer numbers, vectors, strings, characters, bits and more.
Custom primitives may support additional atoms.
Murmel's type system (and JMurmel's corresponding host types) look like so:
;; Murmel type ; description or "Murmel form -> Java class used in JMurmel"
t
cons ; (cons 1 2) -> ConsCell
atom ; all Murmel objects except cons cells
; and all Java Objects are atoms
symbol ; 'sym -> LambdaJSymbol
null ; nil -> null
; nil is the only object of type null
number ; java.lang.Number is accepted for reading
float ; 2.3 -> java.lang.Double
integer ; 42 -> java.lang.Long
; only 54 bits are used
character ; #\A -> java.lang.Character
random-state ; (make-random-state) -> java.util.Random
vector ; (make-array NN t t) -> java.util.ArrayList
; (make-array NN t CC) -> java.util.ArrayList
; makes an ArrayList w/ size NN and initial capacity CC
; java.util.List is acceptable for seqref and seqset
simple-vector ; (make-array NN t nil) -> Object[]
; #(1 2 3) -> Object[]
string ; (make-array NN 'character t) -> java.lang.StringBuilder
; java.lang.StringBuffer is acceptable for sref and sset
; java.lang.CharSequence is accepted for sref
simple-string ; (make-array NN 'character nil) -> char[]
; "abc" -> java.lang.String
bit-vector ; (make-array NN 'bit t) -> BitVector
simple-bit-vector ; (make-array NN 'bit nil) -> boolean[]
: #*0101 -> boolean[]
hash-table ; (make-hash-table [test [size]])
; #H(eql one 1 two 2 three 3) -> EqlMap
; (make-hash-table ['eql [size]]) -> EqlMap
; (make-hash-table ['equal [size]]) -> EqualMap
; (make-hash-table 'eq [size]) -> java.util.IdentityHashMap
; (make-hash-table 't [size]) -> java.util.HashMap
; java.util.Map is acceptable for hashref, hashset, clrhash...
function ; (lambda (param) param) -> Closure or MurmelFunction
(list ::= cons | null)
(sequence ::= list | vector)
;; Murmel's condition type hierarchy is a subset of CL's condition type hierarchy,
;; `error` and subtypes are pretty much the same. Murmel doesn't have multiple
;; inheritance, though, and `reader-error` only extends `stream-error`.
;; JMurmel maps conditions to Java exceptions as best as possible.
condition java.lang.Throwable
error java.lang.Exception
(murmel-error LambdaJError extends RuntimeException extends Exception)
;;; extends LambdaJError
simple-error SimpleError extends LambdaJError
cell-error CellError extends LambdaJError
unbound-variable UnboundVariable extends CellError extends LambdaJError
undefined-function UndefinedFunction extends CellError extends LambdaJError
control-error ControlError extends LambdaJError
program-error ProgramError extends LambdaJError
parse-error SExpressionReader.ParseError extends LambdaJError
arithmetic-error java.lang.ArithmeticException extends RuntimeException
(overflow, underflow)
type-error java.lang.ClassCastException extends RuntimeException
simple-type-error SimpleTypeError extends ClassCastException
invalid-index-error InvalidIndexError extends IndexOutOfBoundsException
file-error java.nio.file.InvalidPathException
extends IllegalArgumentException extends RuntimeException
stream-error java.io.IOException
end-of-file java.io.EOFException extends IOException
reader-error ReaderError extends IOException
NOTE:
CL's reader-error has two superclasses: stream-error and parse-error
if c was a reader-error then both
(typep c 'stream-error) and (typep c 'parse-error) are true
The above is a subset of CLtL2's predefined data types,
see "CLtL2 2. Data Types" https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node15.html
Murmel's condition hierarchy is a subset of CLtL2 predefined condition types,
see "CLtL2 29.5. Predefined Condition Types" https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node346.html
and "CLHS 9.1.1 Condition Types" http://clhs.lisp.se/Body/09_aa.htm
Murmel treats symbols case-insensitive.
Symbol names are of arbitrary length, however only the
first 30 chars are significant.
Implementation note: JMurmel preserves the
capitalization of the first encounter of a symbol
for printing, e.g.:
'(AbC . dEf) -> (AbC . dEf)
but
'(AbC . abc) -> (AbC . AbC)
'*a-sample-symbol*
'a\ symbol\ with\ spaces!
Empty list, printed as `nil`
()
Shorthand for empty list
nil
Tokens that consist of a sign or digit followed by digits
are interpreted as integer numbers (java.lang.Long)
1
Datatype float: a number in double precision
numbers that contain the characters '.eE' are interpreted
as floating point numbers (java.lang.Double)
1.0
a float in scientific notation
1e3
Stringliterals may have a maximum length of 2000 chars.
Stringliterals of the same value are coalesced (interned).
"a string literal"
"another 'literal' \"string literal\""
## Reserved words
In addition to `nil` and `t` the symbols of the special forms are reserved, i.e.
may not be used as a function nor as a variable:
nil, t,
lambda, quote, cond, labels, if, define, defun, let, let*, letrec,
setq, progn, catch, thwrow, unwind-protect, try,
multiple-value-bind, multiple-value-call,
macrolet, defmacro, declaim, load, require, provide
## Variables and Scope
Symbols are bound to global variables using `define` or `defun`
(see below), and to local variables using `let, let*, letrec` or
lambda parameter lists.
Murmel's global bindings are lexical and must be defined before use,
i.e. a symbol is bound to
a newly created variable when define or defun are actually executed.
The symbol's binding as well as the variable's extent (lifetime)
last to the end of the program (the symbol's binding may be
temporarily replaced by a local or dynamic binding, though).
Murmel's local bindings are lexical, i.e. a symbol is bound to
a newly created variable when a `let/let*/letrec/lambda` form
is evaluated. The symbol's binding as well as the associated variable
are removed when leaving the lexical scope of the `let/let*/letrec/lambda`
form, restoring any previously existing binding (which may have
been local or global).
Except: `let* dynamic` will treat global symbols as "special", see below.
## Additional Special Forms
### (define symbol [optional-object]) -> symbol
`define` binds symbols in the global environment with
memory locations that hold values.
Murmel's `define` is somewhat similar to Common Lisp's `defparameter`
except:
CL's `defparameter` creates special global variables while
Murmel's `define` creates global variables that can be
lexically hidden by e.g. a let-binding.
The first argument is not evaluated, the second one - if given - is.
The second argument to `define` is optional and defaults to `nil`.
(define *global-var* 42) ; ==> *gloval-var*
(define f1 (lambda (p1 p2) (+ p1 p2))) ; ==> f1
`define` forms can appear inside toplevel `let, let*, letrec, multiple-value-bind, labels` forms.
### (defun symbol (params\*) [docstring] forms\*) -> symbol
`defun` is a shorthand for defining functions:
(defun symbol (params*) forms*)
<=>
(define symbol (lambda (params*) forms*))
An optional docstring is ignored.
Arguments to `defun` are not evaluated.
(defun f2 (p1 p2) (+ p1 p2)) ; ==> f2
`defun` forms can appear inside toplevel `let, let*, letrec, multiple-value-bind, labels` forms
and will bind a globally visible symbol to a closure (aka let-over-lambda):
(let ((counter 0))
(defun pre-increment-counter ()
(setq counter (1+ counter)))
(defun pre-decrement-counter ()
(setq counter (1- counter)))
(defun peek-counter ()
counter))
(pre-increment-counter) ; ==> 1
(pre-increment-counter) ; ==> 2
(pre-decrement-counter) ; ==> 1
(peek-counter) ; ==> 1
### (defmacro name (params\*) [docstring] forms\*) -> symbol<br/>(defmacro name) -> prev-name
`defmacro` defines a macro, similar to CL's `defmacro`.
Macros are somewhat similar to functions:
On a function application the functions's arguments
are eval'd and the result of the function will be used as is.
On a macro application the macro's arguments are
NOT eval'd, but the result of the macro is.
IOW a function produces a value, a macro application
produces code that will be eval'd.
Macros are defined in a macro namespace.
All macros are in the global scope, i.e. macros
are not scoped but once defined they are visible everywhere.
`(defmacro name)` can be used to unbind previously
defined macros.
An optional docstring is ignored.
(defmacro twice (arg) (list '* arg 2)) ; ==> twice
(twice 3) ; ==> 6.0
(defmacro twice) ; ==> twice; macro is unbound
(defmacro twice) ; ==> twice; no-op
### (setq symbol value [more-symbols more-values]\*) -> last-value
`setq` updates the value(s) of the given global or local symbol(s).
In interpreted Murmel undefined variables will be created on the fly,
in compiled mode variables must have been defined previously.
(define a nil)
(let ((b nil) (c nil))
(setq a 1 b 2 c (+ a b))) ; ==> 3.0
### (if condform form [optionalform]) -> result
(if nil 'YASSS! 'OHNOOO!!!) ; ==> OHNOOO!!!
### (progn forms\*) -> result
(if t (progn (write 'abc) (write 'def)))
### (cond (condform forms\*)\* [(t forms\*)]) -> result
### (labels ((symbol (params\*) forms\*)\*) forms\*) -> result
### (let [optsymbol] ((symbol bindingform)\*) bodyforms\*) -> result
Works similar to CL's `let` with the addition
of Scheme's "named let".
The let-bound variables `symbol` as well as `optsymbol` - if given -
are bound inside bodyforms.
`optsymbol` will be bound inside `bodyforms` to a lambda
whose parameters are the let-variables and whose code is
`bodyforms`. Therefore `optsymbol` can be used for
recursive calls within `bodyforms`.
(let loop ((x 3)
(msg "hi"))
(if (= x 0)
(write msg)
(progn (write (floor x)) (loop (- x 1) msg))))
### (let dynamic ((symbol bindingform)\*) bodyforms\*) -> result
Similar to `let` except: globals are not shadowed but temporarily
bound to the given value, and the previous value is restored when
leaving the scope of the `let` form.
I.e. `let dynamic` treats globals as "special".
Example:
(setq a 1)
(define b 2)
(defun f () (write (cons a b)))
(f)
(let dynamic ((a 11) (b a))
(f))
(f)
will print `(1 . 2)(11 . 1)(1 . 2)`.
### (let* [optsymbol] ((symbol bindingform)\*) bodyforms\*) -> result
Works like `let` (see above) with the addition:
each `bindingform` "sees" the previous symbols. If multiple
let-bindings use the same symbol the last one hides
preceeding ones.
(let* loop ((y 10)
(x (+ y 20))
(x (floor (/ x 10)))
(msg 'hi))
(if (= x 0)
(write msg)
(progn (write (floor x)) (loop 0 0 (- x 1) msg))))
### (let* dynamic ((symbol bindingform)\*) bodyforms\*) -> result
Similar to `let*` except: globals are not shadowed but temporarily
bound to the given value, and the previous value is restored when
leaving the scope of the `let*` form.
I.e. `let* dynamic` treats globals as "special".
(define *g* 'global)
(defun fun () (write *g*))
(let* dynamic ((*g* 'temp)) (fun)) ; fun will write temp
*g* ; ==> 'global
### (letrec [optsybol] ((symbol bindingform)\*) bodyforms\*) -> result
`letrec` works like `let` and `let*` except each bindingform "sees"
all other let symbols as well as it's own symbol.
All symbols are bound, but only the preceeding bindings
are defined (have a value) while eval'ing the `bindingform`.
That way a let-bound variable could be a recursive lambda.
(letrec ((x 1) (y (+ x 1))) (write y))
### (macrolet ((symbol params [docstring] forms)\*) forms\*) -> result
Since: 1.4.7
`macrolet` defines local macros and executes `forms` using the local definitions.
It is an error to shadow local macros with a local function (see `labels`)
or with a named-let loop label.
A docstring if given will be ignored.
### (catch tagform forms\*) -> result
Since: 1.3
`catch` is used as the destination of a non-local control transfer by `throw`.
### (throw tagform resultform) -> |
Since: 1.3
`throw` causes a non-local control transfer to a `catch` whose tag is `eq` to tag.
TODO: If there is no outstanding catch tag that matches the throw tag,
no unwinding of the stack is performed, and an error of type control-error is signaled.
### (unwind-protect protected-form cleanupforms\*) -> result
Since: 1.3
`unwind-protect` evaluates `protected-form` and guarantees that `cleanup-forms`
are executed before unwind-protect exits, whether it terminates normally or is aborted
by a control transfer of some kind.
### (try protected-form . error-obj) -> result
Since 1.4
`try` evaluates `protected-form`. If no error occurred during evaluation then
the values from `protected-form` are the final result.
If an error occurs then `try` returns the `error-obj` if given or null as the primary result,
the secondary result is the condition.
Example:
(multiple-value-bind (result condition)
(try (1+ most-positive-fixnum) 'error)
(if (eq result 'error)
(progn (write "an error occurred: " nil)
(write condition)
'bummer)
result))
; ==> bummer
### (multiple-value-call function-form values-forms\*) -> result
Since: 1.2
`multiple-value-call` first evaluates the `function-form` to obtain function,
and then evaluates each `values-form`. All the values of each form
are gathered together (not just one value from each) and given as arguments
to the function.
(multiple-value-call + 0.0 (values 1 2) 3) ; ==> 6.0
### (multiple-value-bind (symbols\*) values-form bodyforms\*) -> result
Since: 1.2
`values-form` is evaluated, and each of the `symbols` is bound
to the respective value returned by that form.
If there are more `symbols` than values returned,
`nil` is assigned to the remaining vars.
If there are more values than symbols, the excess values are discarded.
The symbols are bound to the values over the execution of the `bodyforms`,
which make up an implicit progn.
(multiple-value-bind (a b) (values 'Hello\, '\ World!)
(jformat nil "%s%s" a b))
==> "Hello, World!"
(multiple-value-bind (a b . c) (values 1 2 3 4 5)
(writeln a) (writeln b) (writeln c))
; 1
; 2
; (3 4 5)
; ==> (3 4 5)
(multiple-value-bind a (values 1 2 3 4 5)
(write a))
; (1 2 3 4 5)
; ==> (1 2 3 4 5)
### (load filespec) -> result
Since: 1.1
Eval the contents of the given file, return value
is the value returned by the last form or nil
in case of an empty file.
When compiling Murmel `load` is performed at
compile time and must appear as a toplevel form.
`filespec` is not eval'd and must be a string.
Unless filespec ends with ".lisp" the file extension
".lisp" will be appended.
If filespec is an absolute path then it will be used as is.
Otherwise the file will be searched in the same directory
as the file that contains the `load` and after that
in "libdir" (set with `--libdir`, "libdir" defaults to the
directory containing jmurmel.jar).
If `load` is entered into the REPL then the file
will be searched in the current directory and then
in the "libdir".
(load "nul") ; ==> nil, NUL is Windows specific
(load "lib") ; will search for lib.lisp and eval it's contents
### (require module-name optional-file-path)
Since: 1.1
Load the given file once. Murmel maintains an internal
set of loaded modules, and `require` will ignore
loading files that were already loaded by comparing
`module-name` to the set of already loaded modules.
When compiling Murmel `require` is performed at
compile time and must appear as a toplevel form.
If `optional-file-path` is omitted or nil then
`module-name` will be used as the file path.
`module-name` and `optional-file-path` are not eval'd
and must be strings.
(require "mlib") ; will search for the file mlib.lisp
; unless the module "mlib" was already loaded
### (provide module-name)
Since: 1.1
Set a file's modulename so that `require` won't
load it twice.
### (declaim (optimize ...
`declaim` currently only supports `optimize`, others will be ignored.
`optimize` only supports speed, others will be ignored.
## Function application
### function call
Applies the operator returned by operatorform to
the eval'd operands
(operatorform operands*)
## Backquote
Backquote "\`" starts "fill-in templates":
backquote, comma and comma-at work similar to CL,
except: comma-dot is not supported.
(setq a 'a-val) (setq b 'b-val) (define c 'c-val)
(define d '(d-val1 d-val2))
`((,a b) ,c ,@d) ; ==> ((a-val b) c-val d-val1 d-val2)
(define y 'b) (define l '(a b))
(eval ``(,a ,,@l ,,y) '((a . a) (b . b) (y . y)))
; ==> (a-val a-val b-val b-val)
(define x '(1 2 3))
`(normal= ,x splicing= ,@x see?)
; ==> (normal= (1 2 3) splicing= 1 2 3 see?)
`(normal= ,x fakesplicing= . ,x)
; ==> (normal= (1 2 3) fakesplicing= 1 2 3)
## Basic Primitives
### (apply form argform) -> result
`form` must eval to a symbol, primitive or lambda.
`argform` must eval to a proper list.
(apply + '(1 2)) ; ==> 3.0
### (eval form) -> result<br/> (eval form env) -> result
`form` will be eval'd, it must return a form.
The optional argument `env` will be eval'd, it must return a list of `(symbol . value)`.
If the optional argument `env` is omitted or `nil`
then the environment for the recursive eval is "all predefined global symbols"
else it is the concatenation of `env` and all predefined globals
(eval '(+ 1 2)) ; ==> 3.0
(eval '(+ x y) (list '(x . 2) '(y . 3))) ; ==> 5.0
(eval '(+ x y) (list (cons 'x 2) (cons 'y 3))) ; ==> 5.0
## Logic, predicates
### (eq x y) -> boolean
Returns `t` if `x` and `y` are the same object, `nil` otherwise.
### (eql x y) -> boolean
Return `t` if any of the following is true
- `a` and `b` are `eq`
- `a` and `b` are numbers of the same type and have the same value
- `a` and `b` are the same characters
Examples:
(eql 2 2) ; ==> t
(eql #\a (sref "aaa" 0)) ; ==> t
(eql -0.0 0.0) ; ==> nil
### (equal a b) -> boolean
Since: 1.4
Return `t` if any of the following is true:
- `a` and `b` are `eql`
- `a` and `b` are strings that have the same text value
- `a` and `b` are bitvectors whose elements are eql
- `a` and `b` are conses whose car and cdr are `equal` respectively
### consp, atom, symbolp, null, listp
### numberp, integerp, floatp
- `numberp` returns `t` for all Murmel and Java number types.
- `integerp` returns `t` for all Murmel and Java integral number types.
- `floatp` returns `t` for Murmel and Java decimal number types.
### characterp
### random-state-p
Since: 1.4.3
### hash-table-p
Since: 1.4
### functionp
Since: 1.3
### vectorp, simple-vector-p
Since: 1.3
### stringp
Return `t` for Murmel strings and all Java Objects implementing java.lang.CharSequence
### simple-string-p, bit-vector-p, simple-bit-vector-p,
Since: 1.3
### (typep obj typespec) -> boolean
Since: 1.4
`typep` returns `t` if `obj` is of type `typespec` or of a subtype.
### (adjustable-array-p obj) -> boolean
Since: 1.3
`adjustable-array-p` returns `t` if `obj` is an adjustable vector.
Note that in Murmel `(adjustable-array-p 1)` returns nil
while in Common Lisp that would signal a `type-error`.
## Conses and lists
### (car list) -> 1st element of list
(car '(a b c)) ; ==> a
### (cdr list) -> rest of list
(cdr '(a b c)) ; ==> (b c)
### (cons e1 e2) -> conscell
(cons 'a 'b) ; ==> (a . b)
### rplaca, rplacd
Replace the value of the CAR or CDR slot of a cons cell.
(setq l '(1 2))
(rplaca l 11) ; ==> (11 2)
(rplacd l 22) ; ==> (11 . 22)
### (list elems\*) -> list<br/>(list\* elems+) -> atom-or-dotted-list
`list` will create a list consisting of it's arguments,
`list*` will create a dotted list.