Emac Manual User Guide. Emac Manual User Guide: Fill & Download for Free

A Common Lisp system is a very interesting environment.It’s similar to a virtual machine (not like JavaVM, but like VmWare or VirtualBox) - you connect to it with your editor, do whatever it is that you want to do, then you can disconnect and the program will continue running. The state of the system at any point in time can also be saved and loaded from disk (like a VM snapshot or Docker container) - you don’t need to create executables, you can just “freeze” the live system and ship the image (very useful when programs are supposed to modify themselves and can have complex dependencies between their code and data - remember, Lisps are from before the AI winter; one of their design goals was to enable Expert systems, Symbolic artificial intelligence).The system itself is organized in packages and symbols, where, in OS terms, the packages would be folders and the symbols would be files. A symbol doesn’t actually have to be some kind of graphical scribble - it can just be a word, like defclass or my-variable. Symbols are also used to represent most Lisp code - for example an expression like (print (+ 100 (get-age person))) can be looked at as a list of two elements - the symbol print and a list of three elements (the symbol +, the number 100, and a list of two symbols, get-age and person).When you’re writing code, referring to symbols that already exist in the current package gives you back those specific symbols - if they don’t exist, they will automatically get added:CL-USER> 'hello HELLO  CL-USER> (describe 'hello) HELLO Type: SYMBOL Class: #<BUILT-IN-CLASS SYMBOL> INTERNAL in package: #<Package "COMMON-LISP-USER"> Print name: "HELLO" Value: #<Unbound> Function: #<Unbound> Plist: NIL  CL-USER> (describe 'defclass) DEFCLASS Type: SYMBOL Class: #<BUILT-IN-CLASS SYMBOL> Macro EXTERNAL in package: #<Package "COMMON-LISP"> Print name: "DEFCLASS" Value: #<Unbound> Function: #<Compiled-function DEFCLASS Macroexpander #x481E4E6> Arglist: (CLASS-NAME SUPERCLASSES SLOTS &REST CLASS-OPTIONS) Plist: NIL The “COMMON-LISP-USER”, or “CL-USER”, is just the default package where you land when you start your Lisp system. The reason we see defclass is because “CL-USER” imports “CL” (a.k.a. “COMMON-LISP”), the “root package” of the Common Lisp standard library.As you can see, symbols have various properties, one of which is their value - what you get when you try to evaluate them (when not quoted):CL-USER> (setf hello 3) 3  CL-USER> hello 3  CL-USER> (describe 'hello) [...] Value: 3 Function: #<Unbound> Plist: NIL Notice the “Plist” slot - this is a place where you can attach arbitrary property-value pairs to the symbol. For example here’s a library that exports a “small” symbol:CL-USER> shapes:small 20  CL-USER> (get 'shapes:small 'shapes:unit) SHAPES::PX  CL-USER> (describe 'shapes:small) SHAPES:SMALL Type: SYMBOL Class: #<BUILT-IN-CLASS SYMBOL> Non-special Variable EXTERNAL in package: #<Package "SHAPES"> Print name: "SMALL" Value: 20 Function: #<Unbound> Plist: (SHAPES::UNIT SHAPES::PX) It’s telling you not only that the value is 20, it’s also telling you what kind of unit of measure is associated with this symbol (pixels). This information is accessible to anybody that works with that symbol, including functions and macros, at run time and compile time.Now, Common Lisp’s macro system is “unhygienic” (in contrast to Scheme’s hygienic macros) - if you don’t use gensym to generate unique non-interned symbols for use in macro expansions, you may get bugs due to accidental capture of variables:CL-USER> (defpackage :my-package (:export :my-macro)) #<Package "MY-PACKAGE">  CL-USER> (in-package :my-package) #<Package "MY-PACKAGE">  MY-PACKAGE> (defmacro my-macro (&body body)  `(let ((a 42))  ,@body  a)) MY-MACRO  MY-PACKAGE> (my-macro (setf a -1)) -1  MY-PACKAGE> (macroexpand '(my-macro (setf a -1))) (LET ((A 42)) (SETF A -1) A) However, that’s where packages come in:MY-PACKAGE> (in-package :cl-user) #<Package "COMMON-LISP-USER">  CL-USER> (my-package:my-macro (setf a -1)) ;Compiler warnings : ; In an anonymous lambda form: Undeclared free variable A 42  CL-USER> (macroexpand '(my-package:my-macro (setf a -1))) (LET ((MY-PACKAGE::A 42)) (SETF A -1) MY-PACKAGE::A)  CL-USER> (describe 'a) [...] INTERNAL in package: #<Package "COMMON-LISP-USER"> Print name: "A" Value: -1 [...] From outside of my-package, you cannot mess with the a in the macroexpansion, since that’s a symbol that’s not accessible to you:CL-USER> (in-package :my-package) #<Package "MY-PACKAGE">  MY-PACKAGE> (describe 'a) [...] INTERNAL in package: #<Package "MY-PACKAGE"> [...]  MY-PACKAGE> (in-package :cl-user) #<Package "COMMON-LISP-USER">  CL-USER> (my-package:my-macro (setf my-package:a -1))  [Debugger pops up]  Reader error: No external symbol named "A" in package #<Package "MY-PACKAGE"> . In Scheme you wouldn’t have had that problem at all, because it manages symbol scope automatically - but the cost is that macros that “pierce” the scope become harder to write. In effect, macros become a bit like a domain-specific language - while CL just sticks to CL for its macros.That bit with the packages can be an interesting source of confusion, though - symbols that are in different packages, even if they have the same textual representation, are not eq:CL-USER> (eq 'my-macro 'my-package:my-macro) NIL Combined with the fact that symbols get automatically interned the first time you use them, in whatever package you currently happen to be, and that you can import packages so their symbols become visible like your own (like how “CL-USER” imports “CL”), without the package name in front:CL-USER> (describe 'eq) EQ Type: SYMBOL Class: #<BUILT-IN-CLASS SYMBOL> Function EXTERNAL in package: #<Package "COMMON-LISP"> Print name: "EQ" Value: #<Unbound> Function: #<Compiled-function EQ #x409803E> Arglist: (CCL::X CCL::Y) Plist: NIL …you can get in a situation where you’ve used a name for something once, and now you can’t import some external package because it contains the same name. Of course, there’s the unintern command, but that’s manual cleanup……Wait, you’re still reading this?Go grab Lispbox and a copy of “Practical Common Lisp” already… after that, maybe “On Lisp” and “Let Over Lambda”. Or maybe “Object Oriented Programming in Common Lisp: A Programmer’s Guide to CLOS” and start trolling the OOP topics on Quora (e.g. “Why do some people use languages that don’t have multimethods?” or “How do I do :before/:after/:around methods in C#?”). And squeeze in an Emacs manual somewhere in there, because commercial Common Lisp IDEs and compilers are friggin’ expensive (and yet, the companies that make them haven’t gone out of business… makes you wonder ;)).NOTE: Some empty lines were added in the code samples, for readability purposes in bland and colorless (or even wrongly-colored) environments like the Quora code blocks. It looks much better in color:

I’m sure someone hit these already, but since I got an A2A:Because you have it precisely backwards. Let’s compare Emacs (which I use every day) with Eclipse (which I at least have used long enough to know where things are in their manual)Manual file management — Define “manual?” I find some of the Emacs file management tools, including good ol’ Tramp and DirEd, much much less “manual” than the tools in Eclipse.No instant error checking — Actually. Eclipse does do a bit of validation for Java code at least, but it’s nowhere near as complete as some of the advanced linting tools in EmacsNo mouse functionality — Um, Emacs has supported a mouse since at least 1981, probably a bit earlier. I think Smalltalk was probably the only system using a mouse in an IDE before that.Irritating UI — Well, I do find that a big problem with eg Eclipse or (so very much) Visual Studio, but at least with Emacs I was able to customize it a great deal to my own comfort. Of course, it’s had a lot longer to work out the kinks.A large number of commands to remember — Wait, what? You’ll love this other invention we added back in the mid-1970’s … all the internal and user commands are cross-referenced by name and description, and most of them have detailed instructions on how to use them interactively, or from Emacs Lisp, right there online.It’s actually so cool, it’s in the first line in the manual: “Emacs is the extensible, customizable, self-documenting real-time display editor.”Just hit your Help key (or F1 or C-h if you don’t have one) and when the minibuffer prompt comes up, hit Help (or F1 or C-h) again for a guide to some of the ways to locate documentation. Depending on your current buffer’s mode, you might also get online documentation for that language or cross-referencing in your own project’s documentation, but you’ll at least get options like the tutorial, the Info documentation reader to read both your operating system and Emacs manuals, as well as things like the “apropos” command to try to see if there’s some command that does what you want.Oh, but most of the time, for most things, I just use that mouse and click on the toolbars or menus.etc. etc.Things Emacs has that no other IDE (except maybe a Vim on a good day) has replicated ensuite:Gracefully manages many hundreds of active buffers.Uniform handling (for the most part) of text and text-like content in hundreds of coding systems and languagesEach mode can be customized or share common features. Perhaps I want bigger headlines in one language buffer than another.Each file’s buffer can likewise be customized. Sometimes that’s just, “Here, let me jack up my zoom to 400% so you can read my screen from over there.”Integration with best available compilers and debuggers for over 100 programming and markup languagesIntegrated back-ends for remote filesystem access over eg. SSH or FTPBuilt-in vector and bitmap graphics functions within “text” buffers for annotationsAlmost 100% remappable keyboard bindings (aside from C-g)Automatic, on-the-fly code formatting, auto-completion, and (at least shallow) static analysis for most languages.Paredit mode and its kin. (Addictive!)Glasses-mode, to split up ugly CamelCaseNames into More⋅Legible⋅Words on the flyTools that auto-correct typos in code. I particularly rely upon a feature that helps reformat names that I type in ususal-hyphenated style into CamelCase or snake_case for me when I’m in “weird” language modes that use ugly names like that ☺Insert-Char, which has a complete dictionary of named Unicode symbols, so I can easily add something like C-x 8 Ret Japan Spc P Spc Spc Ret → “Japanese Post Office” \U0001f3e3. Of course, that (like most auto-completing hint tools) pops up a nice preview window with possible completion names and the glyphs alongside them.Integrated applications that are often useful enough. I won’t argue that all of them are super-complete and compete with, say, LibreOffice, but things like Org-mode are great partly because they’re easy to integrate into the workflow. Tbl mode is a “good enough” spreadsheet for 80% of my needs and easy to export to Calc or Sheets when (if) something outgrows it.Built-in communications and messaging. Yes, I can read and compose e-mail, net news, chat, and more.99.9% customizable in Emacs Lisp.Mean time between failures: about 2 weeks. But I’m an abusive user, most users report much longer, I think.Integration with RCS, CVS, Subversion, Git, Bazaar, and other vcs software.Interactive Customize system for setting most preferences and often some very deep customization of features without scripting.One key (combo) to send a selection to a Unix program and capture the output.Remote-control from scripts. Script has an error? See if I have Emacs open and report it there.So, on a typical day, I might have some Unix-style Groff manual pages open (in Woman mode), the Info hypertext manual browser, probably a Common Lisp Slime session or two with some associated Lisp and ASDF source files, REPLs, debuggers, inspectors, and the windows that those programs might have opened, maybe some OpenGL canvas or CLIM windows; probably a few services running in Emacs that I’m testing on the other screen in Firefox or something, which is being “puppetted” by Emacs remote-controlling it through MozREPL and Selenium; perhaps some scripts in Perl, Bourne Shell, Ruby, and Python, HTML and CSS files, LaTeΧ markup source files, a C program with its own debugger processes, a couple of Makefiles and their compilation traces, all hypertext-linked from each warning back to related source code, regardless of the compiler or language, and maybe some good ol’ 6502 or x86–64 assembly language. Plus, an e-mail I’m composing with a patch to someone’s code attached that I copied from the integrated Git version control processes, some terminal shell windows, some graphs, a GraphVis chart, and two different kinds of project management systems, plus chat windows.But all that has a price. That weighs in at almost 500M of RAM.

Emacs community is healthy and active right now.It’s simply because you misunderstood the graph, here is the text quoted from google trends manual,The numbers that appear show total searches for a term relative to the total number of searches done on Google over time. A line trending downward means that a search term's relative popularity is decreasing. But that doesn’t necessarily mean the total number of searches for that term is decreasing. It just means its popularity is decreasing compared to other searches.For example, currently there more job opportunities for Linux junior developers/administrators. Junior people will search vi because it’s bundled with Linux. That’s why Emacs looks less popular than Vi. Both users are increasing, but Emacs users are increasing slowly.That’s actually an advantage. The high chance to talk with experienced developers is the reason I love Emacs community.If you want to know why Emacs is popular in Elite developers and how to be one of them, please read “Master Emacs in One Year” (redguardtoo/mastering-emacs-in-one-year-guide).