= newlisp-libmisc.a(8)
:doctype: manpage
:revdate: {sys:date "+%Y-%m-%d %H:%M:%S"}

== NAME

newlisp-libmisc.a - Newlisp archive comprosing useful functions.

== SYNOPSIS

.With packnl (example)
packnl _main.lsp_ *-A newlisp-libmisc.a*


.With incore.lsp
(load "incore.lsp") +
(archive "newlisp-libmisc.a") +
(load "misc.lsp")

== DESCRIPTION

*newlisp-libmisc.a* is a newlisp archive file that provides loadable
modules with utility functions.

=== misc.lsp API

(prog1 [_term_]*)::

The *prog1* function is like a *begin* function except that it returns
the value of the first term rather than the last.

(die _N_ [_term_]*)::

The *die* function printes to stderr the join of term values as
strings with space separation, and if _N_ is a number, then the
function exits the program with that return code.
+
.Example of stderr logging
(die nil 'This "is" 'printed "to stderr")

(octal-byte _B_)::
Print binary byte as octal or as ASCII character [32-126].

(octals-string _S_)::
Print string as a succesion of +octal-byte+.

(human-byte _B_)::
Return byte code as printable (string) or as code (number).

(human-bytes _BL_)::

Return a list of human-byte elements from a list of byte codes but
also joining consecutive string elements to form packed strings.

=== foop.lsp API

This newlisp module provides Functional Object-Oriented Programming
(FOOP) modelling support.

FOOP is an abstraction overlay using the newlisp context notion as a
simile to the _class_ notion in genuine object-oriented programming
languages. This is set out in newlisp by means of the representation
principle that an instance of a FOOP "class" (i.e. context) is a list
headed by the context itself, and followed by the "member values".

FOOP further includes by the "method invocation" syntax where a
function is preceded by ':' and then followed by the instance
concerned before actual function arguments. That instance is then
stoved away as implicitly available via the (self) function, and the
member values accessible via index, e.g. the term (self 3) refers to
the third member of the instance. The self references are
destructively assignable with setf.

This modelling support adds member name declaration together with
automatic getter and setter defintions. The (FOOP ...) term is used
for declaring member names in order. For example:

(FOOP [_name_])::

*FOOP* is like a language extension to declare the field names of a
FOOP class, and thereby gain "get" and "set" functions generated with
the respective naming formats (:%name obj) and (:!name obj value).

.illustration 
----
(context 'MAIN:EX)
(FOOP here there more)
(define (EX HERE THERE MORE) (list (context) HERE THERE MORE))

(context MAIN)
(setf A (EX 1 2 3))
--> A = (EX 1 2 3)
(:!there A 4)
--> A = (EX 1 4 3)
----

=== mmap.lsp API

This newlisp module implements a small FOOP model based memory mapping
API that links in the _libc6_ functions _mmap_, _munmap_, _msync_ and
_lseek_.

(*MMap* _FD_ _LENGTH_ [_OFFSET_ [_PROT_]])::

This function creates a FOOP object that represents the memory mapping
of the given file descriptor. _FD_ may be the pathname string of a
file to memory map or an already opened file descriptor. The MMap
object represents the memory block starting at (:%base) and (%len)
bytes in length where the file is memory mapped.
+
.Access example (from test.lsp)
[caption=""]
----
(println (setf X (MMap "mmap.lsp")))
(println (get-string (:%base X)))
----
+
Note that only a plain text file would be accessed with _get-string_.
A binary file would rather be accessed with _unpack_. The memory
mapping provides read-only "random access" to the file content.
+
To set up read-write acces requires an _OFFSET_ and the _PROT_
argument 0x3, and writing should be accompanied by _MMap:msync_ calls
so as to synchronize with the backing file.
+
The FOOP object includes get and set methods for the fields (in
order): _base_, _len_, _prot_, _flags_, _fd_ and _offset_.

=== test.lsp

This file is a small test of the MMap memory mapping.

== SEE ALSO

*newlisp*

== AUTHOR

Ralph Ronnquist <ralph.ronnquist@gmail.com>