- * (funcall (lambda (x y) (list x y y)) :toy :choo)
-
- (:TOY :CHOO :CHOO)
- * "Hello World"
-
- "Hello World"
- *
-
-Many people like to run SBCL, like other Lisp systems, as a subprocess
-under Emacs. The Emacs "ilisp" mode provides many convenient features,
-like command line editing, tab completion, and various kinds of
-coupling between Common Lisp source files and the interactive SBCL
-subprocess, but can be somewhat fragile because it tries to be so
-clever and intimate in its interactions with the Lisp subprocess. In
-case of ilisp problems, running SBCL in the Emacs "shell" mode can a
-useful substitute.
-
-.SH OVERVIEW
-
-SBCL compiles Common Lisp to native code. (Even today, some 30 years
-after the MacLisp compiler, people will tell you that Lisp is an
-interpreted language. Ignore them.)
-
-SBCL aims for but has not completely achieved compliance with the ANSI
-standard for Common Lisp. More information about this is available in
-the BUGS section below.
-
-SBCL also includes various non-ANSI extensions.
-
-Many Lispy extensions have been retained from CMU CL:
-.TP 3
-\--
-CMU-CL-style safe implementation of type declarations:
-"Declarations are assertions."
-.TP 3
-\--
-the source level debugger (very similar to CMU CL's)
-.TP 3
-\--
-the profiler (now somewhat different from CMU CL's)
-.TP 3
-\--
-saving the state of the running SBCL process, producing a
-"core" file which can be restarted later
-.TP 3
-\--
-Gray streams (a de-facto standard system of overloadable CLOS classes
-whose instances can be used wherever ordinary ANSI streams can be used)
-.TP 3
-\--
-weak pointers and finalization (which have unfortunately
-suffered from at least some code rot, so that e.g. weak hash
-tables don't work)
-.PP
-
-Fundamental system interface extensions are also provided:
-.TP 3
-\--
-calling out to C code (a.k.a. FFI, foreign function interface,
-with very nearly the same interface as CMU CL)
-.TP 3
-\--
-some simple support for operations with a "scripting language"
-flavor, e.g. reading POSIX argc and argv, or executing a
-subprogram
-.PP
-
-.SH DIFFERENCES FROM CMU CL
-
-SBCL can be built from scratch using a plain vanilla ANSI Common Lisp
-system and a C compiler, and all of its properties are specified by
-the version of the source code that it was created from. This clean
-bootstrappability was the immediate motivation for forking off of the
-CMU CL development tree. A variety of implementation differences are
-motivated by this design goal.
-
-Maintenance work in SBCL since the fork has diverged somewhat from the
-maintenance work in CMU CL. Many but not all bug fixes and
-improvements have been shared between the two projects, and sometimes
-the two projects disagree about what would be an improvement.
-
-Most extensions supported by CMU CL are not supported in SBCL,
-including Motif support, the Hemlock editor, search paths, the
-low-level Unix interface, the WIRE protocol, multithreading, various
-user-level macros and functions (e.g. LETF, ITERATE, MEMQ,
-REQUIRED-ARGUMENT), and many others.
-
-SBCL has retained some extensions from parent CMU CL. Many of the
-retained extensions are in these categories:
-.TP 3
-\--
-things which might be in the new ANSI spec, e.g. safe type
-declarations, weak pointers, finalization, foreign function
-interface to C, and Gray streams
-.TP 3
-\--
-things which are universally available in Unix scripting languages,
-e.g. RUN-PROGRAM and POSIX argv and getenv
-.TP 3
-\--
-hooks into the low level workings of the system which can be useful
-for debugging, e.g. requesting that a particular function be executed
-whenever GC occurs, or tuning compiler diagnostic output
-.TP 3
-\--
-unportable performance hacks, e.g. FREEZE-TYPE and PURIFY. For more
-information about these, look at the online documentation for symbols
-in the SB-EXT package, and look at the user manual.
-.PP
-
-There are also a few retained extensions which don't fall into any
-particular category, e.g. the ability to save running Lisp images as
-executable files.
-
-Some of the retained extensions have new names and/or different
-options than their CMU CL counterparts. For example, the SBCL function
-which saves a Lisp image to disk and kills the running process is
-called SAVE-LISP-AND-DIE instead of SAVE-LISP, and SBCL's
-SAVE-LISP-AND-DIE supports fewer keyword options than CMU CL's
-SAVE-LISP does.
-
-(Why doesn't SBCL support more extensions? Why drop all those nice
-extensions from CMU CL when the code already exists? This is a
-frequently asked question on the mailing list. In some cases, it's a
-design philosophy issue: arguably SBCL has done its job by supplying a
-stable FFI, and the right design decision is to move functionality
-derived from that, like socket support, into separate libraries,
-distributed as separate software packages by separate maintainers. In
-other cases it's a practical decision, hoping that focusing on a
-smaller number of things will let us do a better job on them. This is
-very much the case for multithreading: it's an important, valuable
-extension, but it's not easy to get right, and especially while SBCL
-is still working on basic ANSI compliance, difficult extensions aren't
-likely to be a priority.)
-
-.SH THE COMPILER
-
-SBCL is essentially a compiler-only implementation of Common Lisp. All
-nontrivial Lisp code is compiled to native machine code before being
-executed, even when the Lisp code is typed interactively at the
-"interpreter" prompt.
-
-SBCL inherits from CMU CL the "Python" native code compiler. (Though
-we often avoid that name in order to avoid confusion with the
-scripting language also called Python.) This compiler is very clever
-about understanding the type system of Common Lisp and using it to
-optimize code, and about producing notes to let the user know when the
-compiler doesn't have enough type information to produce efficient
-code. It also tries (almost always successfully) to follow the unusual
-but very useful principle that "declarations are assertions", i.e.
-type declarations should be checked at runtime unless the user
-explicitly tells the system that speed is more important than safety.