150 lines
4.3 KiB
Org Mode
150 lines
4.3 KiB
Org Mode
* The Sex language
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Sex is a S-expressions language. Sex is written in Chicken, which is a
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[[https://call-cc.org][R5RS Scheme]].
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Sex is statically typed, compiled general purpose language.
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* Compilation
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First, get yourself a Chicken, then, some Chicken deps. You also will
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need a C compiler.
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** Install Chicken Eggs
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Tip: there's a way to make Chicken install eggs non-globally. You need
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to export ~CHICKEN_INSTALL_REPOSITORY~ and ~CHICKEN_REPOSITORY_PATH~
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environment variables. Refer to the documentation for more info:
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https://wiki.call-cc.org/man/5/Extension%20tools#changing-the-repository-location
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~chicken-install fmt getopt-long brev-separate test tree srfi-1 srfi-13 srfi-69 matchable~
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** Compilation
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~make~
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* Usage
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** Summary
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#+begin_src
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Usage: sexc [options] filename [-- options-for-c-compiler]
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Options:
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--c-compiler=ARG Select C compiler. Defaults to value of SEX_CC
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environment variable, or if it is empty, to cc
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-c, --compile-object Compile object file instead of executable program
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-C, --preprocess Emit C code
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--public-interface Get module's public interface
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-h, --help Show this help
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-m, --macro-expand Emit macro-expanded semantically processed Sex code
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(sort of IR). May be useful for debugging
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-o, --output=ARG Write output to file. Default file name is a.out.
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If -E or -m options are provided, defaults to stdout
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#+end_src
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** Compiling Hello World
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#+begin_src shell
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sexc ./examples/hello-world.sex -o hello
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#+end_src
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That's it. Now you should have executable named ~hello~ in your
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directory. Sex uses C under the hood, the default C compiler is ~cc~,
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but you can pass any using ~--c-compiler~ option, or by setting
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~SEX_CC~ environment variable.
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** Example
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An example of Sex source:
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#+begin_src scheme
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(include stdio.h)
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(pub fn int main ((int argc) (char **argv))
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(puts "Hello from Sex!")
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(var (array char 512) name)
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(puts "What is your name?")
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(scanf "%s" (cast char* &name))
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(printf "Hello, %s!\n" name)
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0)
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#+end_src
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Compile and run:
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#+begin_src shell
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~/dev/sex $ ./sexc ./example/hello-world.sex -o hello-world
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~/dev/sex $ ./hello-world
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Hello from Sex!
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What is your name?
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Alex
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Hello, Alex!
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#+end_src
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* Features
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** Full C interoperability
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Just ~(include "Your/Favourite/Library.h")~ and use it as you would
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have is C.
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*** Auto kebabification
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For hardcore fans of traditional Lisp naming convention,
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Sex offers automatic kebabification of all symbols, i.e. no more
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ugly ~GL_ARRAY_BUFFER~ s in your code, they may be written in their
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proper form: ~GL-ARRAY-BUFFER~.
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** Modules
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Each source file is a module. Module can provide public interface and
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be imported by using ~(import path/to/module)~ expression. Module
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search path consists of two parts: first is relative to the source
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being compiled location, and the second is ~SEX_MODULE_PATH~
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environment variable.
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Module's public interface consists of everything declared
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~pub~. Structures, function, macros, types, variables can be
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public.
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** Syntactic macros
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Sex has support for syntactic macros. Macro definitions look like
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functions: they have a name, an argument list and a body. Macro should
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return Sex code.
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*** Examples:
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**** Structure with templated value type
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#+begin_src scheme
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(pub defmacro (list-T type)
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(let ((list-type (cat 'list- type)))
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`(struct ,list-type
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((,type value)
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((* ,list-type) next)))))
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(list-T int)
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#+end_src
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->
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#+begin_src scheme
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(struct list_int
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((int value)
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((* list_int) next)))
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#+end_src
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**** Wrapper for checking return codes
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#+begin_src scheme
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(pub defmacro (check-sdl-return call message ret-code)
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`(if (< 0 ,call)
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(begin
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(puts ,message)
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(return ,ret-code)))))
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(pub fn int init ()
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(check-sdl-return
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(SDL-Init SDL-INIT-VIDEO) "Failed to initialize SDL" 1)
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...)
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#+end_src
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->
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#+begin_src c
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(%fun int init ()
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(if (< 0 (SDL_Init SDL_INIT_VIDEO))
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(%begin (puts "Failed to initialize SDL") (return 1)))
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...)
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}
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#+end_src
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** Use an established environment for development
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As Sex is S-expressions, you always have Emacs with paredit as your
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best option.
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*** sex-mode.el
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To harness the power of sex-mode, add the following lines to your
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~$HOME/.config/emacs/init.el~:
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#+begin_src emacs-lisp
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(use-package sex-mode
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:load-path "/path/to/sex"
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:mode ("\\.sex\\'"))
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#+end_src
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