Truth and Falsehood in Emacs Lisp nil explained nil has two meanings. Buffer Related Review Review. Buffer Exercises The Definition of mark-whole-buffer mark-whole-buffer overview Body of mark-whole-buffer Only three lines of code. The Definition of append-to-buffer append-to-buffer overview append interactive A two part interactive expression. Second Buffer Related Review optional Exercise The Definition of insert-buffer insert-buffer code insert-buffer interactive When you can read, but not write.
Insert or How the or expression works. Insert let Two save-excursion expressions. New insert-buffer The Interactive Expression in insert-buffer Read-only buffer When a buffer cannot be modified. Complete Definition of beginning-of-buffer Optional Arguments beginning-of-buffer opt arg Example with optional argument. Digression into C Minor note on C programming language macros.
Summing up zap-to-char Using point and search-forward. Lisp macro copy-region-as-kill Complete copy-region-as-kill The complete function definition.
- An Introduction to Programming in Emacs LISP by Robert J Chassell - .
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Loops and Recursion while Causing a stretch of code to repeat. Looping exercise while Looping with while Repeat so long as test returns true. Loop Example A while loop that uses a list. Incrementing Loop A loop with an incrementing counter. Inc Example parts The parts of the function definition. Inc Example altogether Putting the function definition together.
Dec Example parts The parts of the function definition. Dec Example altogether Putting the function definition together. Save your time: dolist and dotimes dolist dotimes Recursion Building Robots Same model, different serial number Recursive Definition Parts Walk until you stop Recursion with list Using a list as the test whether to recurse. Recursive triangle function Recursion with cond Recursive Patterns Often used templates.
No Deferment Don't store up work Regexp Review re-search Exercises forward-sentence Complete forward-sentence fwd-sentence while loops Two while loops. Counting Exercise The count-words-example Function Design count-words-example The definition using a while loop. Whitespace Bug The Whitespace Bug in count-words-example. Syntax What constitutes a word or symbol? Several defuns Counting several defuns in a file. Find a File Do you want to look at a file?
Several files Counting in definitions in different files. Several files recursively Recursively counting in different files. Prepare the data Prepare the data for display in a graph. Count Words in defuns in Different Files lengths-list-many-files Return a list of the lengths of defuns. Files List Making a list of files. Counting function definitions Readying a Graph Columns of a graph graph-body-print How to print the body of a graph. Beginning init File How to write a. Text and Auto-fill Automatically wrap lines.
An Introduction to Programming in Emacs Lisp
Mail Aliases Use abbreviations for email addresses. Keymaps More about key binding. Loading Files Load i. Autoload Make functions available. Simple Extension Define a function; bind it to a key. X11 Colors Colors in X. Miscellaneous Mode Line How to customize your mode line. Debugging debug How to use the built-in debugger. Print Whole Graph The function to print a complete graph.
Compute a Remainder How to compute the remainder of a division. Y Axis Element Construct a line for the Y axis. Y-axis-column Generate a list of Y axis labels. X Axis Tic Marks Create tic marks for the horizontal axis. Printing the Whole Graph The final version A few changes. Test print-graph Run a short test. Graphing words in defuns Executing the final code. Another Bug Yet another bug Final printed graph The graph itself!
Practicing Evaluation. Free Software and Free Manuals. Variable Number of Arguments.
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Typing editing commands or C-x C-e causes evaluation. Interactive multiply-by-seven. Uninitialized let Variables.
Template for save-excursion. Shows goto-char , point-min , and push-mark. Uses save-excursion and insert-buffer-substring. Body of mark-whole-buffer. Second Buffer Related Review. However, because errors in C code can easily lead to segmentation violations or to more subtle bugs, which crash the editor, and because writing C code that interacts correctly with the Emacs Lisp garbage collector is error-prone, the number of functions implemented as primitives is kept to a necessary minimum.
Byte-compiling can make Emacs Lisp code execute faster. Emacs contains a compiler which can translate Emacs Lisp source files into a special representation termed bytecode. Emacs Lisp bytecode files have the filename suffix ". Compared to source files, bytecode files load faster, occupy less space on the disk, use less memory when loaded, and run faster. Bytecode still runs more slowly than primitives, but functions loaded as bytecode can be easily modified and re-loaded.
In addition, bytecode files are platform-independent. The standard Emacs Lisp code distributed with Emacs is loaded as bytecode, although the matching source files are usually provided for the user's reference as well. User-supplied extensions are typically not byte-compiled, as they are neither as large nor as computationally intensive. Notably, the "cl" package implements a fairly large subset of Common Lisp. Emacs Lisp unlike some other Lisp implementations does not do tail-call optimization.
The apel library aids in writing portable Emacs Lisp code, with the help of the polysylabi platform bridge. Emacs Lisp is a Lisp-2 meaning that it has a function namespace which is separate from the namespace it uses for other variables. Like MacLisp, Emacs Lisp uses dynamic scope , offering static or lexical as an option starting from version In dynamic scoping, if a programmer declares a variable within the scope of a function, it is available to subroutines called from within that function.
Originally, this was intended as an optimization ; lexical scoping was still uncommon and of uncertain performance. However, dynamic scoping has several disadvantages. Firstly, it can easily lead to bugs in large programs, due to unintended interactions between variables in different functions. Secondly, accessing variables under dynamic scoping is generally slower than under lexical scoping. Also, the lexical-let macro in the "cl" package does provide effective lexical scope to Emacs Lisp programmers, but while "cl" is widely used, lexical-let is rarely used.
From Wikipedia, the free encyclopedia. Emacs Lisp Emacs logo. Archived from the original on Retrieved If you know Common Lisp, you will notice many similarities. However, many features of Common Lisp have been omitted or simplified in order to reduce the memory requirements of GNU Emacs. Sometimes the simplifications are so drastic that a Common Lisp user might be very confused. In doing this, I aimed to make the absolute minimal possible Lisp implementation.
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The size of the programs was a tremendous concern. There were people in those days, in , who had one-megabyte machines without virtual memory. They wanted to be able to use GNU Emacs. This meant I had to keep the program as small as possible. Lisp programming language. Automatic storage management Conditionals Dynamic typing Higher-order functions Linked lists M-expressions deprecated Read—eval—print loop Recursion S-expressions Self-hosting compiler Tree data structures.
Lisp machines TI Explorer. Edmund Berkeley Daniel G. Bobrow William Clinger R. Scott Fahlman Richard P. Gabriel David A. Moon Kent Pitman Guy L. Steele Jr. Daniel Weinreb. Shriram Krishnamurthi Guy L. Gerald Jay Sussman Julie Sussman. Category Category List. Conkeror Dissociated press Editor war Spacemacs. Emacs on Wikimedia Commons Emacs on Wikiquotes. Free and open-source software portal.
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An introduction to Emacs Lisp