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diff --git a/chicken-5.org b/chicken-5.org new file mode 100644 index 0000000..4f71755 --- /dev/null +++ b/chicken-5.org @@ -0,0 +1,324 @@ +* What's cool about CHICKEN 5? +#+STARTUP: inlineimages + [[./chicken-logo.png]] + + +** Peter Bex + + T-DOSE + Eindhoven + May 11th, 2019 + +* Who am I? + +** Peter Bex + +*** Work: codeyellow.nl + We're hiring! Talk to me or Burhan later +*** Freelancing on the side: pebble-software.nl +*** Blog (mostly about CHICKEN): more-magic.net + +*** Fell in love with Scheme at university, ~2002 +*** CHICKEN user since 2003 + eggs: postgresql, spiffy, http-client, ... +*** CHICKEN core contributor since late 2009 + regex engine, macros, garbage collector, ... +* Scheme: intro + Dialect of /LISP/, a functional language (impure) + LISP is from 1958, Scheme 1975; still here! + + Other Lisps: Common Lisp, Emacs Lisp, Clojure, .. + Not for everyone -> Love it or hate it! +#+BEGIN_SRC scheme + (display "Hello, world!\n") ;; Obligatory + + (define (fib n) ;; Fibonacci, because why not + (if (<= n 2) + 1 + (+ (fib (- n 1)) + (fib (- n 2))))) +#+END_SRC + +* Scheme: philosophy + +** Super minimal but powerful language + User is an equal to the makers of the language + + Very few things *need* "special" support + + Advantages of small extensible core: + - ease of understanding (fits in your head) + - embeddability + - facilitates experimental implementations + - timelessness; e.g. classes can just be a + library. C => C++/ObjC, Pascal => Object Pascal + but Scheme => Scheme +* Scheme superpowers: macros + +** Fully hygienic macro system +#+BEGIN_SRC scheme + (define-syntax swap! + (syntax-rules () + ((_ a b) (let ((x a)) + (set! a b) + (set! b x))))) + + ;; Does the right thing, i.e. print 2: + (let ((x 1) (y 2)) + (swap! x y) + (display y)) +#+END_SRC + +* Scheme superpowers: closures + +** Lexical scoping + + Gives us *closures* (now ubiquitous; first LISP) +#+BEGIN_SRC scheme + (define (make-counter) + (let ((val 0)) + (lambda () ; Anonymous fn, closes over "val" + (set! val (+ val 1)) + val))) + (define c (make-counter)) + (c) ; 1 + (c) ; 2 +#+END_SRC + +* Scheme superpowers: continuations + +** Continuations + + Can be used to implement exceptions, co-routines, + serialize full program state, etc etc + + Tail calls "for free" [Lambda the Ultimate Goto] + Tail recursion is /required by the spec/! + Bad implementations often conveniently ignore it + + Deep recursion is okay; just eats up more heap + + See also Stackless Python + +* Scheme superpowers: numeric tower + +** Numeric tower + +Systematic support for /all the numbers/ +Spec defines system, subset is allowed (see later) +#+BEGIN_SRC scheme +1 ;; exact integer +0.5 ;; inexact real number +1/2 ;; exact rational number +1+2i ;; exact complex number +0.5+0.25i ;; inexact complex number +1/2+3/4i ;; ALSO an exact complex number +(+ 3/4 1/2) ;; yes, this returns 5/4 +#+END_SRC + +* CHICKEN: intro + + /Implementation/ of Scheme (one of the few + serious ones) + + Based on Henry Baker's [Cheney On The MTA] idea: + Use C stack for initial heap (nursery) + + Been around since 2000. + + Compiles to C. Uses GCC, clang, ... to generate + machine code, so: very portable + + *Great* community! Produced lots of libraries + +* CHICKEN: C interop + + Interop with C is trivial; just drop down to it +#+BEGIN_SRC scheme + (import (chicken foreign)) + + (foreign-declare "#include <math.h>") + + (define twice-exp + (foreign-lambda* double ((double x)) + "double result = exp(x);" + "C_return(result * 2.0);")) + + (display (twice-exp 5)) ;; 296.826318205153 +#+END_SRC + +* CHICKEN 5: Overhaul of module system + +** Most user-visible change + Old CHICKENs had such memorable module names as + "utils" and "extras"... Most was in "chicken" + + Hard to remember, inconsistent + + Large libraries (but few imports needed) + +** Naming scheme (haha) inspired by R7RS + (scheme base) => (chicken base) + (scheme file) => (chicken file) etc + others: (chicken posix), (chicken foreign) etc +* CHICKEN 5: Overhaul of module system; examples + +** A few good examples to give you an idea: + "sort" procedure in CHICKEN 4: data-structures + "sort" procedure in CHICKEN 5: (chicken sort) + + "symbol-append" in CHICKEN 4: library?! chicken + "symbol-append" in CHICKEN 5: (chicken base) + + "->string" in CHICKEN 4: data-structures + "->string" in CHICKEN 5: (chicken string) + + "read-line" in CHICKEN 4: extras + "read-line" in CHICKEN 5: (chicken io) + +* CHICKEN 5: Numeric tower; old situation + +** Older CHICKENs had only "fixnums" and "flonums" + +*** Quite fast (compile to ~standard C float/int) + +*** Never felt very "complete" or "serious" to me + LISP/Scheme is awesome, dammit! + +*** Issues with C FFI + Only 62 (or 30) bits available for ints; + precision loss + +** So, I made it my mission to fix this + +* CHICKEN 5: Numeric tower; new situation + +** Most important: large integers ("bignums") + C FFI finally supports /size_t/ and friends! + +** Exact rational numbers are nice too; + Calculations will always be exact + +** Complex numbers mostly for completeness + Not that many use-cases(?) + +** Pretty fast, but a bit slower than CHICKEN 4 + Mostly due to pre-allocation. Working on it! +*** Enough self-promotion, on to other features +* CHICKEN 5: static compilation + +** Great for binary deployment / distribution + No need to mess around with "virtualenvs" etc + + Just plop the binary onto a server; done + + Killer feature of Go, for example + +** CHICKEN always supported static compilation! + Sucked for eggs (nobody tests it) + +** Solution: declarative egg format + Makes it harder to mess up +* CHICKEN 5: static compilation; old situation + +** Old (imperative) .setup-file format: +#+BEGIN_SRC scheme + (compile -s ncurses.scm -L -lncurses -j ncurses) + (compile -s ncurses.import.scm) + (compile -c ncurses.scm -L -lncurses + -unit ncurses) ; Almost nobody did this + + (install-extension + 'ncurses + '("ncurses.o" "ncurses.so" "ncurses.import.so") + '((version "1.6") + (static "ncurses.o"))) ; And this +#+END_SRC scheme + +* CHICKEN 5: static compilation; new situation + +** New (declarative) .egg-file format: +#+BEGIN_SRC scheme + ((synopsis "An interface to ncurses") + (category ui) + (license "BSD") + (build-dependencies bind) + (author "felix winkelmann") + (maintainer "The CHICKEN Team") + ;; This replaces the .setup file: + (components (extension ncurses + (link-options -L -lncurses)))) +#+END_SRC scheme + +* CHICKEN 5: declarative egg files; sh scripts + +** Generates sh scripts (batch files on Windows) +#+BEGIN_SRC sh + chicken-do ncurses.so ncurses.import.scm : \ + ncurses.scm ncurses.egg : \ + csc -host -J -s -setup-mode -I . -C -I. \ + -L -lncurses ncurses.scm -o ncurses.so + + chicken-do ncurses.static.o ncurses.link : \ + ncurses.scm ncurses.egg : \ + csc -setup-mode -static -I . -emit-link-file \ + ncurses.link -host -c -unit ncurses \ + -C -I. ncurses.scm -o ncurses.static.o +#+END_SRC + +* CHICKEN 5: declarative egg files; advantages + +** Advantages of declarative format + + Static linking is *always* built-in + + Cross-compilation is made easier + + Support for new features can be retroactively + added to all eggs + + Security + + Less typing! + +* CHICKEN 5: binary reproducible builds + +** Both CHICKEN itself and eggs + + Made output of Scheme to C conversion stable + C to binary is left to the C tool chain + +** Gives us verifiability + + See also [reproducible-builds.org] + +** Nice bonus: Faster builds with ccache + + Generated C is identical! + +* Final words + +** Most important eggs have already been ported! + CHICKEN 5 is recommended for new code + +** Start porting your CHICKEN 4 code + How-to guide: wiki.call-cc.org/porting-c4-to-c5 + +** CHICKEN 5.1 is upcoming +*** Bugfixes, perf improvements, cleanups + The usual + +*** New "c-objects" declaration in egg files + Some eggs will require 5.1! + +* Thank you! + [[./chicken-logo.png]] + +** CHICKEN website + call-cc.org + +** IRC channel + #chicken on Freenode + +** My blog + more-magic.net diff --git a/chicken-logo.png b/chicken-logo.png Binary files differnew file mode 100644 index 0000000..f936457 --- /dev/null +++ b/chicken-logo.png |
