+++ /dev/null
-This is Info file ../../info/lispref.info, produced by Makeinfo version
-1.68 from the input file lispref.texi.
-
-INFO-DIR-SECTION XEmacs Editor
-START-INFO-DIR-ENTRY
-* Lispref: (lispref). XEmacs Lisp Reference Manual.
-END-INFO-DIR-ENTRY
-
- Edition History:
-
- GNU Emacs Lisp Reference Manual Second Edition (v2.01), May 1993 GNU
-Emacs Lisp Reference Manual Further Revised (v2.02), August 1993 Lucid
-Emacs Lisp Reference Manual (for 19.10) First Edition, March 1994
-XEmacs Lisp Programmer's Manual (for 19.12) Second Edition, April 1995
-GNU Emacs Lisp Reference Manual v2.4, June 1995 XEmacs Lisp
-Programmer's Manual (for 19.13) Third Edition, July 1995 XEmacs Lisp
-Reference Manual (for 19.14 and 20.0) v3.1, March 1996 XEmacs Lisp
-Reference Manual (for 19.15 and 20.1, 20.2, 20.3) v3.2, April, May,
-November 1997 XEmacs Lisp Reference Manual (for 21.0) v3.3, April 1998
-
- Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Free Software
-Foundation, Inc. Copyright (C) 1994, 1995 Sun Microsystems, Inc.
-Copyright (C) 1995, 1996 Ben Wing.
-
- Permission is granted to make and distribute verbatim copies of this
-manual provided the copyright notice and this permission notice are
-preserved on all copies.
-
- Permission is granted to copy and distribute modified versions of
-this manual under the conditions for verbatim copying, provided that the
-entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
- Permission is granted to copy and distribute translations of this
-manual into another language, under the above conditions for modified
-versions, except that this permission notice may be stated in a
-translation approved by the Foundation.
-
- Permission is granted to copy and distribute modified versions of
-this manual under the conditions for verbatim copying, provided also
-that the section entitled "GNU General Public License" is included
-exactly as in the original, and provided that the entire resulting
-derived work is distributed under the terms of a permission notice
-identical to this one.
-
- Permission is granted to copy and distribute translations of this
-manual into another language, under the above conditions for modified
-versions, except that the section entitled "GNU General Public License"
-may be included in a translation approved by the Free Software
-Foundation instead of in the original English.
-
-\1f
-File: lispref.info, Node: Big5 and Shift-JIS Functions, Prev: Detection of Textual Encoding, Up: Coding Systems
-
-Big5 and Shift-JIS Functions
-----------------------------
-
- These are special functions for working with the non-standard
-Shift-JIS and Big5 encodings.
-
- - Function: decode-shift-jis-char CODE
- This function decodes a JISX0208 character of Shift-JIS
- coding-system. CODE is the character code in Shift-JIS as a cons
- of type bytes. The corresponding character is returned.
-
- - Function: encode-shift-jis-char CH
- This function encodes a JISX0208 character CH to SHIFT-JIS
- coding-system. The corresponding character code in SHIFT-JIS is
- returned as a cons of two bytes.
-
- - Function: decode-big5-char CODE
- This function decodes a Big5 character CODE of BIG5 coding-system.
- CODE is the character code in BIG5. The corresponding character
- is returned.
-
- - Function: encode-big5-char CH
- This function encodes the Big5 character CHAR to BIG5
- coding-system. The corresponding character code in Big5 is
- returned.
-
-\1f
-File: lispref.info, Node: CCL, Next: Category Tables, Prev: Coding Systems, Up: MULE
-
-CCL
-===
-
- CCL (Code Conversion Language) is a simple structured programming
-language designed for character coding conversions. A CCL program is
-compiled to CCL code (represented by a vector of integers) and executed
-by the CCL interpreter embedded in Emacs. The CCL interpreter
-implements a virtual machine with 8 registers called `r0', ..., `r7', a
-number of control structures, and some I/O operators. Take care when
-using registers `r0' (used in implicit "set" statements) and especially
-`r7' (used internally by several statements and operations, especially
-for multiple return values and I/O operations).
-
- CCL is used for code conversion during process I/O and file I/O for
-non-ISO2022 coding systems. (It is the only way for a user to specify a
-code conversion function.) It is also used for calculating the code
-point of an X11 font from a character code. However, since CCL is
-designed as a powerful programming language, it can be used for more
-generic calculation where efficiency is demanded. A combination of
-three or more arithmetic operations can be calculated faster by CCL than
-by Emacs Lisp.
-
- *Warning:* The code in `src/mule-ccl.c' and
-`$packages/lisp/mule-base/mule-ccl.el' is the definitive description of
-CCL's semantics. The previous version of this section contained
-several typos and obsolete names left from earlier versions of MULE,
-and many may remain. (I am not an experienced CCL programmer; the few
-who know CCL well find writing English painful.)
-
- A CCL program transforms an input data stream into an output data
-stream. The input stream, held in a buffer of constant bytes, is left
-unchanged. The buffer may be filled by an external input operation,
-taken from an Emacs buffer, or taken from a Lisp string. The output
-buffer is a dynamic array of bytes, which can be written by an external
-output operation, inserted into an Emacs buffer, or returned as a Lisp
-string.
-
- A CCL program is a (Lisp) list containing two or three members. The
-first member is the "buffer magnification", which indicates the
-required minimum size of the output buffer as a multiple of the input
-buffer. It is followed by the "main block" which executes while there
-is input remaining, and an optional "EOF block" which is executed when
-the input is exhausted. Both the main block and the EOF block are CCL
-blocks.
-
- A "CCL block" is either a CCL statement or list of CCL statements.
-A "CCL statement" is either a "set statement" (either an integer or an
-"assignment", which is a list of a register to receive the assignment,
-an assignment operator, and an expression) or a "control statement" (a
-list starting with a keyword, whose allowable syntax depends on the
-keyword).
-
-* Menu:
-
-* CCL Syntax:: CCL program syntax in BNF notation.
-* CCL Statements:: Semantics of CCL statements.
-* CCL Expressions:: Operators and expressions in CCL.
-* Calling CCL:: Running CCL programs.
-* CCL Examples:: The encoding functions for Big5 and KOI-8.
-
-\1f
-File: lispref.info, Node: CCL Syntax, Next: CCL Statements, Prev: CCL, Up: CCL
-
-CCL Syntax
-----------
-
- The full syntax of a CCL program in BNF notation:
-
-CCL_PROGRAM :=
- (BUFFER_MAGNIFICATION
- CCL_MAIN_BLOCK
- [ CCL_EOF_BLOCK ])
-
-BUFFER_MAGNIFICATION := integer
-CCL_MAIN_BLOCK := CCL_BLOCK
-CCL_EOF_BLOCK := CCL_BLOCK
-
-CCL_BLOCK :=
- STATEMENT | (STATEMENT [STATEMENT ...])
-STATEMENT :=
- SET | IF | BRANCH | LOOP | REPEAT | BREAK | READ | WRITE
- | CALL | END
-
-SET :=
- (REG = EXPRESSION)
- | (REG ASSIGNMENT_OPERATOR EXPRESSION)
- | integer
-
-EXPRESSION := ARG | (EXPRESSION OPERATOR ARG)
-
-IF := (if EXPRESSION CCL_BLOCK [CCL_BLOCK])
-BRANCH := (branch EXPRESSION CCL_BLOCK [CCL_BLOCK ...])
-LOOP := (loop STATEMENT [STATEMENT ...])
-BREAK := (break)
-REPEAT :=
- (repeat)
- | (write-repeat [REG | integer | string])
- | (write-read-repeat REG [integer | ARRAY])
-READ :=
- (read REG ...)
- | (read-if (REG OPERATOR ARG) CCL_BLOCK CCL_BLOCK)
- | (read-branch REG CCL_BLOCK [CCL_BLOCK ...])
-WRITE :=
- (write REG ...)
- | (write EXPRESSION)
- | (write integer) | (write string) | (write REG ARRAY)
- | string
-CALL := (call ccl-program-name)
-END := (end)
-
-REG := r0 | r1 | r2 | r3 | r4 | r5 | r6 | r7
-ARG := REG | integer
-OPERATOR :=
- + | - | * | / | % | & | '|' | ^ | << | >> | <8 | >8 | //
- | < | > | == | <= | >= | != | de-sjis | en-sjis
-ASSIGNMENT_OPERATOR :=
- += | -= | *= | /= | %= | &= | '|=' | ^= | <<= | >>=
-ARRAY := '[' integer ... ']'
-
-\1f
-File: lispref.info, Node: CCL Statements, Next: CCL Expressions, Prev: CCL Syntax, Up: CCL
-
-CCL Statements
---------------
-
- The Emacs Code Conversion Language provides the following statement
-types: "set", "if", "branch", "loop", "repeat", "break", "read",
-"write", "call", and "end".
-
-Set statement:
-==============
-
- The "set" statement has three variants with the syntaxes `(REG =
-EXPRESSION)', `(REG ASSIGNMENT_OPERATOR EXPRESSION)', and `INTEGER'.
-The assignment operator variation of the "set" statement works the same
-way as the corresponding C expression statement does. The assignment
-operators are `+=', `-=', `*=', `/=', `%=', `&=', `|=', `^=', `<<=',
-and `>>=', and they have the same meanings as in C. A "naked integer"
-INTEGER is equivalent to a SET statement of the form `(r0 = INTEGER)'.
-
-I/O statements:
-===============
-
- The "read" statement takes one or more registers as arguments. It
-reads one byte (a C char) from the input into each register in turn.
-
- The "write" takes several forms. In the form `(write REG ...)' it
-takes one or more registers as arguments and writes each in turn to the
-output. The integer in a register (interpreted as an Emchar) is
-encoded to multibyte form (ie, Bufbytes) and written to the current
-output buffer. If it is less than 256, it is written as is. The forms
-`(write EXPRESSION)' and `(write INTEGER)' are treated analogously.
-The form `(write STRING)' writes the constant string to the output. A
-"naked string" `STRING' is equivalent to the statement `(write
-STRING)'. The form `(write REG ARRAY)' writes the REGth element of the
-ARRAY to the output.
-
-Conditional statements:
-=======================
-
- The "if" statement takes an EXPRESSION, a CCL BLOCK, and an optional
-SECOND CCL BLOCK as arguments. If the EXPRESSION evaluates to
-non-zero, the first CCL BLOCK is executed. Otherwise, if there is a
-SECOND CCL BLOCK, it is executed.
-
- The "read-if" variant of the "if" statement takes an EXPRESSION, a
-CCL BLOCK, and an optional SECOND CCL BLOCK as arguments. The
-EXPRESSION must have the form `(REG OPERATOR OPERAND)' (where OPERAND is
-a register or an integer). The `read-if' statement first reads from
-the input into the first register operand in the EXPRESSION, then
-conditionally executes a CCL block just as the `if' statement does.
-
- The "branch" statement takes an EXPRESSION and one or more CCL
-blocks as arguments. The CCL blocks are treated as a zero-indexed
-array, and the `branch' statement uses the EXPRESSION as the index of
-the CCL block to execute. Null CCL blocks may be used as no-ops,
-continuing execution with the statement following the `branch'
-statement in the containing CCL block. Out-of-range values for the
-EXPRESSION are also treated as no-ops.
-
- The "read-branch" variant of the "branch" statement takes an
-REGISTER, a CCL BLOCK, and an optional SECOND CCL BLOCK as arguments.
-The `read-branch' statement first reads from the input into the
-REGISTER, then conditionally executes a CCL block just as the `branch'
-statement does.
-
-Loop control statements:
-========================
-
- The "loop" statement creates a block with an implied jump from the
-end of the block back to its head. The loop is exited on a `break'
-statement, and continued without executing the tail by a `repeat'
-statement.
-
- The "break" statement, written `(break)', terminates the current
-loop and continues with the next statement in the current block.
-
- The "repeat" statement has three variants, `repeat', `write-repeat',
-and `write-read-repeat'. Each continues the current loop from its
-head, possibly after performing I/O. `repeat' takes no arguments and
-does no I/O before jumping. `write-repeat' takes a single argument (a
-register, an integer, or a string), writes it to the output, then jumps.
-`write-read-repeat' takes one or two arguments. The first must be a
-register. The second may be an integer or an array; if absent, it is
-implicitly set to the first (register) argument. `write-read-repeat'
-writes its second argument to the output, then reads from the input
-into the register, and finally jumps. See the `write' and `read'
-statements for the semantics of the I/O operations for each type of
-argument.
-
-Other control statements:
-=========================
-
- The "call" statement, written `(call CCL-PROGRAM-NAME)', executes a
-CCL program as a subroutine. It does not return a value to the caller,
-but can modify the register status.
-
- The "end" statement, written `(end)', terminates the CCL program
-successfully, and returns to caller (which may be a CCL program). It
-does not alter the status of the registers.
-
-\1f
-File: lispref.info, Node: CCL Expressions, Next: Calling CCL, Prev: CCL Statements, Up: CCL
-
-CCL Expressions
----------------
-
- CCL, unlike Lisp, uses infix expressions. The simplest CCL
-expressions consist of a single OPERAND, either a register (one of `r0',
-..., `r0') or an integer. Complex expressions are lists of the form `(
-EXPRESSION OPERATOR OPERAND )'. Unlike C, assignments are not
-expressions.
-
- In the following table, X is the target resister for a "set". In
-subexpressions, this is implicitly `r7'. This means that `>8', `//',
-`de-sjis', and `en-sjis' cannot be used freely in subexpressions, since
-they return parts of their values in `r7'. Y may be an expression,
-register, or integer, while Z must be a register or an integer.
-
-Name Operator Code C-like Description
-CCL_PLUS `+' 0x00 X = Y + Z
-CCL_MINUS `-' 0x01 X = Y - Z
-CCL_MUL `*' 0x02 X = Y * Z
-CCL_DIV `/' 0x03 X = Y / Z
-CCL_MOD `%' 0x04 X = Y % Z
-CCL_AND `&' 0x05 X = Y & Z
-CCL_OR `|' 0x06 X = Y | Z
-CCL_XOR `^' 0x07 X = Y ^ Z
-CCL_LSH `<<' 0x08 X = Y << Z
-CCL_RSH `>>' 0x09 X = Y >> Z
-CCL_LSH8 `<8' 0x0A X = (Y << 8) | Z
-CCL_RSH8 `>8' 0x0B X = Y >> 8, r[7] = Y & 0xFF
-CCL_DIVMOD `//' 0x0C X = Y / Z, r[7] = Y % Z
-CCL_LS `<' 0x10 X = (X < Y)
-CCL_GT `>' 0x11 X = (X > Y)
-CCL_EQ `==' 0x12 X = (X == Y)
-CCL_LE `<=' 0x13 X = (X <= Y)
-CCL_GE `>=' 0x14 X = (X >= Y)
-CCL_NE `!=' 0x15 X = (X != Y)
-CCL_ENCODE_SJIS `en-sjis' 0x16 X = HIGHER_BYTE (SJIS (Y, Z))
- r[7] = LOWER_BYTE (SJIS (Y, Z)
-CCL_DECODE_SJIS `de-sjis' 0x17 X = HIGHER_BYTE (DE-SJIS (Y, Z))
- r[7] = LOWER_BYTE (DE-SJIS (Y, Z))
-
- The CCL operators are as in C, with the addition of CCL_LSH8,
-CCL_RSH8, CCL_DIVMOD, CCL_ENCODE_SJIS, and CCL_DECODE_SJIS. The
-CCL_ENCODE_SJIS and CCL_DECODE_SJIS treat their first and second bytes
-as the high and low bytes of a two-byte character code. (SJIS stands
-for Shift JIS, an encoding of Japanese characters used by Microsoft.
-CCL_ENCODE_SJIS is a complicated transformation of the Japanese
-standard JIS encoding to Shift JIS. CCL_DECODE_SJIS is its inverse.)
-It is somewhat odd to represent the SJIS operations in infix form.
-
-\1f
-File: lispref.info, Node: Calling CCL, Next: CCL Examples, Prev: CCL Expressions, Up: CCL
-
-Calling CCL
------------
-
- CCL programs are called automatically during Emacs buffer I/O when
-the external representation has a coding system type of `shift-jis',
-`big5', or `ccl'. The program is specified by the coding system (*note
-Coding Systems::.). You can also call CCL programs from other CCL
-programs, and from Lisp using these functions:
-
- - Function: ccl-execute CCL-PROGRAM STATUS
- Execute CCL-PROGRAM with registers initialized by STATUS.
- CCL-PROGRAM is a vector of compiled CCL code created by
- `ccl-compile'. It is an error for the program to try to execute a
- CCL I/O command. STATUS must be a vector of nine values,
- specifying the initial value for the R0, R1 .. R7 registers and
- for the instruction counter IC. A `nil' value for a register
- initializer causes the register to be set to 0. A `nil' value for
- the IC initializer causes execution to start at the beginning of
- the program. When the program is done, STATUS is modified (by
- side-effect) to contain the ending values for the corresponding
- registers and IC.
-
- - Function: ccl-execute-on-string CCL-PROGRAM STATUS STR &optional
- CONTINUE
- Execute CCL-PROGRAM with initial STATUS on STRING. CCL-PROGRAM is
- a vector of compiled CCL code created by `ccl-compile'. STATUS
- must be a vector of nine values, specifying the initial value for
- the R0, R1 .. R7 registers and for the instruction counter IC. A
- `nil' value for a register initializer causes the register to be
- set to 0. A `nil' value for the IC initializer causes execution
- to start at the beginning of the program. An optional fourth
- argument CONTINUE, if non-nil, causes the IC to remain on the
- unsatisfied read operation if the program terminates due to
- exhaustion of the input buffer. Otherwise the IC is set to the end
- of the program. When the program is done, STATUS is modified (by
- side-effect) to contain the ending values for the corresponding
- registers and IC. Returns the resulting string.
-
- To call a CCL program from another CCL program, it must first be
-registered:
-
- - Function: register-ccl-program NAME CCL-PROGRAM
- Register NAME for CCL program PROGRAM in `ccl-program-table'.
- PROGRAM should be the compiled form of a CCL program, or nil.
- Return index number of the registered CCL program.
-
- Information about the processor time used by the CCL interpreter can
-be obtained using these functions:
-
- - Function: ccl-elapsed-time
- Returns the elapsed processor time of the CCL interpreter as cons
- of user and system time, as floating point numbers measured in
- seconds. If only one overall value can be determined, the return
- value will be a cons of that value and 0.
-
- - Function: ccl-reset-elapsed-time
- Resets the CCL interpreter's internal elapsed time registers.
-
-\1f
-File: lispref.info, Node: CCL Examples, Prev: Calling CCL, Up: CCL
-
-CCL Examples
-------------
-
- This section is not yet written.
-
-\1f
-File: lispref.info, Node: Category Tables, Prev: CCL, Up: MULE
-
-Category Tables
-===============
-
- A category table is a type of char table used for keeping track of
-categories. Categories are used for classifying characters for use in
-regexps - you can refer to a category rather than having to use a
-complicated [] expression (and category lookups are significantly
-faster).
-
- There are 95 different categories available, one for each printable
-character (including space) in the ASCII charset. Each category is
-designated by one such character, called a "category designator". They
-are specified in a regexp using the syntax `\cX', where X is a category
-designator. (This is not yet implemented.)
-
- A category table specifies, for each character, the categories that
-the character is in. Note that a character can be in more than one
-category. More specifically, a category table maps from a character to
-either the value `nil' (meaning the character is in no categories) or a
-95-element bit vector, specifying for each of the 95 categories whether
-the character is in that category.
-
- Special Lisp functions are provided that abstract this, so you do not
-have to directly manipulate bit vectors.
-
- - Function: category-table-p OBJ
- This function returns `t' if ARG is a category table.
-
- - Function: category-table &optional BUFFER
- This function returns the current category table. This is the one
- specified by the current buffer, or by BUFFER if it is non-`nil'.
-
- - Function: standard-category-table
- This function returns the standard category table. This is the
- one used for new buffers.
-
- - Function: copy-category-table &optional TABLE
- This function constructs a new category table and return it. It
- is a copy of the TABLE, which defaults to the standard category
- table.
-
- - Function: set-category-table TABLE &optional BUFFER
- This function selects a new category table for BUFFER. One
- argument, a category table. BUFFER defaults to the current buffer
- if omitted.
-
- - Function: category-designator-p OBJ
- This function returns `t' if ARG is a category designator (a char
- in the range `' '' to `'~'').
-
- - Function: category-table-value-p OBJ
- This function returns `t' if ARG is a category table value. Valid
- values are `nil' or a bit vector of size 95.
-
-\1f
-File: lispref.info, Node: Tips, Next: Building XEmacs and Object Allocation, Prev: MULE, Up: Top
-
-Tips and Standards
-******************
-
- This chapter describes no additional features of XEmacs Lisp.
-Instead it gives advice on making effective use of the features
-described in the previous chapters.
-
-* Menu:
-
-* Style Tips:: Writing clean and robust programs.
-* Compilation Tips:: Making compiled code run fast.
-* Documentation Tips:: Writing readable documentation strings.
-* Comment Tips:: Conventions for writing comments.
-* Library Headers:: Standard headers for library packages.
-
-\1f
-File: lispref.info, Node: Style Tips, Next: Compilation Tips, Up: Tips
-
-Writing Clean Lisp Programs
-===========================
-
- Here are some tips for avoiding common errors in writing Lisp code
-intended for widespread use:
-
- * Since all global variables share the same name space, and all
- functions share another name space, you should choose a short word
- to distinguish your program from other Lisp programs. Then take
- care to begin the names of all global variables, constants, and
- functions with the chosen prefix. This helps avoid name conflicts.
-
- This recommendation applies even to names for traditional Lisp
- primitives that are not primitives in XEmacs Lisp--even to `cadr'.
- Believe it or not, there is more than one plausible way to define
- `cadr'. Play it safe; append your name prefix to produce a name
- like `foo-cadr' or `mylib-cadr' instead.
-
- If you write a function that you think ought to be added to Emacs
- under a certain name, such as `twiddle-files', don't call it by
- that name in your program. Call it `mylib-twiddle-files' in your
- program, and send mail to `bug-gnu-emacs@prep.ai.mit.edu'
- suggesting we add it to Emacs. If and when we do, we can change
- the name easily enough.
-
- If one prefix is insufficient, your package may use two or three
- alternative common prefixes, so long as they make sense.
-
- Separate the prefix from the rest of the symbol name with a hyphen,
- `-'. This will be consistent with XEmacs itself and with most
- Emacs Lisp programs.
-
- * It is often useful to put a call to `provide' in each separate
- library program, at least if there is more than one entry point to
- the program.
-
- * If a file requires certain other library programs to be loaded
- beforehand, then the comments at the beginning of the file should
- say so. Also, use `require' to make sure they are loaded.
-
- * If one file FOO uses a macro defined in another file BAR, FOO
- should contain this expression before the first use of the macro:
-
- (eval-when-compile (require 'BAR))
-
- (And BAR should contain `(provide 'BAR)', to make the `require'
- work.) This will cause BAR to be loaded when you byte-compile
- FOO. Otherwise, you risk compiling FOO without the necessary
- macro loaded, and that would produce compiled code that won't work
- right. *Note Compiling Macros::.
-
- Using `eval-when-compile' avoids loading BAR when the compiled
- version of FOO is *used*.
-
- * If you define a major mode, make sure to run a hook variable using
- `run-hooks', just as the existing major modes do. *Note Hooks::.
-
- * If the purpose of a function is to tell you whether a certain
- condition is true or false, give the function a name that ends in
- `p'. If the name is one word, add just `p'; if the name is
- multiple words, add `-p'. Examples are `framep' and
- `frame-live-p'.
-
- * If a user option variable records a true-or-false condition, give
- it a name that ends in `-flag'.
-
- * Please do not define `C-c LETTER' as a key in your major modes.
- These sequences are reserved for users; they are the *only*
- sequences reserved for users, so we cannot do without them.
-
- Instead, define sequences consisting of `C-c' followed by a
- non-letter. These sequences are reserved for major modes.
-
- Changing all the major modes in Emacs 18 so they would follow this
- convention was a lot of work. Abandoning this convention would
- make that work go to waste, and inconvenience users.
-
- * Sequences consisting of `C-c' followed by `{', `}', `<', `>', `:'
- or `;' are also reserved for major modes.
-
- * Sequences consisting of `C-c' followed by any other punctuation
- character are allocated for minor modes. Using them in a major
- mode is not absolutely prohibited, but if you do that, the major
- mode binding may be shadowed from time to time by minor modes.
-
- * You should not bind `C-h' following any prefix character (including
- `C-c'). If you don't bind `C-h', it is automatically available as
- a help character for listing the subcommands of the prefix
- character.
-
- * You should not bind a key sequence ending in <ESC> except following
- another <ESC>. (That is, it is ok to bind a sequence ending in
- `<ESC> <ESC>'.)
-
- The reason for this rule is that a non-prefix binding for <ESC> in
- any context prevents recognition of escape sequences as function
- keys in that context.
-
- * Applications should not bind mouse events based on button 1 with
- the shift key held down. These events include `S-mouse-1',
- `M-S-mouse-1', `C-S-mouse-1', and so on. They are reserved for
- users.
-
- * Modes should redefine `mouse-2' as a command to follow some sort of
- reference in the text of a buffer, if users usually would not want
- to alter the text in that buffer by hand. Modes such as Dired,
- Info, Compilation, and Occur redefine it in this way.
-
- * When a package provides a modification of ordinary Emacs behavior,
- it is good to include a command to enable and disable the feature,
- Provide a command named `WHATEVER-mode' which turns the feature on
- or off, and make it autoload (*note Autoload::.). Design the
- package so that simply loading it has no visible effect--that
- should not enable the feature. Users will request the feature by
- invoking the command.
-
- * It is a bad idea to define aliases for the Emacs primitives. Use
- the standard names instead.
-
- * Redefining an Emacs primitive is an even worse idea. It may do
- the right thing for a particular program, but there is no telling
- what other programs might break as a result.
-
- * If a file does replace any of the functions or library programs of
- standard XEmacs, prominent comments at the beginning of the file
- should say which functions are replaced, and how the behavior of
- the replacements differs from that of the originals.
-
- * Please keep the names of your XEmacs Lisp source files to 13
- characters or less. This way, if the files are compiled, the
- compiled files' names will be 14 characters or less, which is
- short enough to fit on all kinds of Unix systems.
-
- * Don't use `next-line' or `previous-line' in programs; nearly
- always, `forward-line' is more convenient as well as more
- predictable and robust. *Note Text Lines::.
-
- * Don't call functions that set the mark, unless setting the mark is
- one of the intended features of your program. The mark is a
- user-level feature, so it is incorrect to change the mark except
- to supply a value for the user's benefit. *Note The Mark::.
-
- In particular, don't use these functions:
-
- * `beginning-of-buffer', `end-of-buffer'
-
- * `replace-string', `replace-regexp'
-
- If you just want to move point, or replace a certain string,
- without any of the other features intended for interactive users,
- you can replace these functions with one or two lines of simple
- Lisp code.
-
- * Use lists rather than vectors, except when there is a particular
- reason to use a vector. Lisp has more facilities for manipulating
- lists than for vectors, and working with lists is usually more
- convenient.
-
- Vectors are advantageous for tables that are substantial in size
- and are accessed in random order (not searched front to back),
- provided there is no need to insert or delete elements (only lists
- allow that).
-
- * The recommended way to print a message in the echo area is with
- the `message' function, not `princ'. *Note The Echo Area::.
-
- * When you encounter an error condition, call the function `error'
- (or `signal'). The function `error' does not return. *Note
- Signaling Errors::.
-
- Do not use `message', `throw', `sleep-for', or `beep' to report
- errors.
-
- * An error message should start with a capital letter but should not
- end with a period.
-
- * Try to avoid using recursive edits. Instead, do what the Rmail `e'
- command does: use a new local keymap that contains one command
- defined to switch back to the old local keymap. Or do what the
- `edit-options' command does: switch to another buffer and let the
- user switch back at will. *Note Recursive Editing::.
-
- * In some other systems there is a convention of choosing variable
- names that begin and end with `*'. We don't use that convention
- in Emacs Lisp, so please don't use it in your programs. (Emacs
- uses such names only for program-generated buffers.) The users
- will find Emacs more coherent if all libraries use the same
- conventions.
-
- * Indent each function with `C-M-q' (`indent-sexp') using the
- default indentation parameters.
-
- * Don't make a habit of putting close-parentheses on lines by
- themselves; Lisp programmers find this disconcerting. Once in a
- while, when there is a sequence of many consecutive
- close-parentheses, it may make sense to split them in one or two
- significant places.
-
- * Please put a copyright notice on the file if you give copies to
- anyone. Use the same lines that appear at the top of the Lisp
- files in XEmacs itself. If you have not signed papers to assign
- the copyright to the Foundation, then place your name in the
- copyright notice in place of the Foundation's name.
-
-\1f
-File: lispref.info, Node: Compilation Tips, Next: Documentation Tips, Prev: Style Tips, Up: Tips
-
-Tips for Making Compiled Code Fast
-==================================
-
- Here are ways of improving the execution speed of byte-compiled Lisp
-programs.
-
- * Use the `profile' library to profile your program. See the file
- `profile.el' for instructions.
-
- * Use iteration rather than recursion whenever possible. Function
- calls are slow in XEmacs Lisp even when a compiled function is
- calling another compiled function.
-
- * Using the primitive list-searching functions `memq', `member',
- `assq', or `assoc' is even faster than explicit iteration. It may
- be worth rearranging a data structure so that one of these
- primitive search functions can be used.
-
- * Certain built-in functions are handled specially in byte-compiled
- code, avoiding the need for an ordinary function call. It is a
- good idea to use these functions rather than alternatives. To see
- whether a function is handled specially by the compiler, examine
- its `byte-compile' property. If the property is non-`nil', then
- the function is handled specially.
-
- For example, the following input will show you that `aref' is
- compiled specially (*note Array Functions::.) while `elt' is not
- (*note Sequence Functions::.):
-
- (get 'aref 'byte-compile)
- => byte-compile-two-args
-
- (get 'elt 'byte-compile)
- => nil
-
- * If calling a small function accounts for a substantial part of
- your program's running time, make the function inline. This
- eliminates the function call overhead. Since making a function
- inline reduces the flexibility of changing the program, don't do
- it unless it gives a noticeable speedup in something slow enough
- that users care about the speed. *Note Inline Functions::.
-
-\1f
-File: lispref.info, Node: Documentation Tips, Next: Comment Tips, Prev: Compilation Tips, Up: Tips
-
-Tips for Documentation Strings
-==============================
-
- Here are some tips for the writing of documentation strings.
-
- * Every command, function, or variable intended for users to know
- about should have a documentation string.
-
- * An internal variable or subroutine of a Lisp program might as well
- have a documentation string. In earlier Emacs versions, you could
- save space by using a comment instead of a documentation string,
- but that is no longer the case.
-
- * The first line of the documentation string should consist of one
- or two complete sentences that stand on their own as a summary.
- `M-x apropos' displays just the first line, and if it doesn't
- stand on its own, the result looks bad. In particular, start the
- first line with a capital letter and end with a period.
-
- The documentation string can have additional lines that expand on
- the details of how to use the function or variable. The
- additional lines should be made up of complete sentences also, but
- they may be filled if that looks good.
-
- * For consistency, phrase the verb in the first sentence of a
- documentation string as an infinitive with "to" omitted. For
- instance, use "Return the cons of A and B." in preference to
- "Returns the cons of A and B." Usually it looks good to do
- likewise for the rest of the first paragraph. Subsequent
- paragraphs usually look better if they have proper subjects.
-
- * Write documentation strings in the active voice, not the passive,
- and in the present tense, not the future. For instance, use
- "Return a list containing A and B." instead of "A list containing
- A and B will be returned."
-
- * Avoid using the word "cause" (or its equivalents) unnecessarily.
- Instead of, "Cause Emacs to display text in boldface," write just
- "Display text in boldface."
-
- * Do not start or end a documentation string with whitespace.
-
- * Format the documentation string so that it fits in an Emacs window
- on an 80-column screen. It is a good idea for most lines to be no
- wider than 60 characters. The first line can be wider if
- necessary to fit the information that ought to be there.
-
- However, rather than simply filling the entire documentation
- string, you can make it much more readable by choosing line breaks
- with care. Use blank lines between topics if the documentation
- string is long.
-
- * *Do not* indent subsequent lines of a documentation string so that
- the text is lined up in the source code with the text of the first
- line. This looks nice in the source code, but looks bizarre when
- users view the documentation. Remember that the indentation
- before the starting double-quote is not part of the string!
-
- * A variable's documentation string should start with `*' if the
- variable is one that users would often want to set interactively.
- If the value is a long list, or a function, or if the variable
- would be set only in init files, then don't start the
- documentation string with `*'. *Note Defining Variables::.
-
- * The documentation string for a variable that is a yes-or-no flag
- should start with words such as "Non-nil means...", to make it
- clear that all non-`nil' values are equivalent and indicate
- explicitly what `nil' and non-`nil' mean.
-
- * When a function's documentation string mentions the value of an
- argument of the function, use the argument name in capital letters
- as if it were a name for that value. Thus, the documentation
- string of the function `/' refers to its second argument as
- `DIVISOR', because the actual argument name is `divisor'.
-
- Also use all caps for meta-syntactic variables, such as when you
- show the decomposition of a list or vector into subunits, some of
- which may vary.
-
- * When a documentation string refers to a Lisp symbol, write it as it
- would be printed (which usually means in lower case), with
- single-quotes around it. For example: `lambda'. There are two
- exceptions: write t and nil without single-quotes. (In this
- manual, we normally do use single-quotes for those symbols.)
-
- * Don't write key sequences directly in documentation strings.
- Instead, use the `\\[...]' construct to stand for them. For
- example, instead of writing `C-f', write `\\[forward-char]'. When
- Emacs displays the documentation string, it substitutes whatever
- key is currently bound to `forward-char'. (This is normally `C-f',
- but it may be some other character if the user has moved key
- bindings.) *Note Keys in Documentation::.
-
- * In documentation strings for a major mode, you will want to refer
- to the key bindings of that mode's local map, rather than global
- ones. Therefore, use the construct `\\<...>' once in the
- documentation string to specify which key map to use. Do this
- before the first use of `\\[...]'. The text inside the `\\<...>'
- should be the name of the variable containing the local keymap for
- the major mode.
-
- It is not practical to use `\\[...]' very many times, because
- display of the documentation string will become slow. So use this
- to describe the most important commands in your major mode, and
- then use `\\{...}' to display the rest of the mode's keymap.
-
-\1f
-File: lispref.info, Node: Comment Tips, Next: Library Headers, Prev: Documentation Tips, Up: Tips
-
-Tips on Writing Comments
-========================
-
- We recommend these conventions for where to put comments and how to
-indent them:
-
-`;'
- Comments that start with a single semicolon, `;', should all be
- aligned to the same column on the right of the source code. Such
- comments usually explain how the code on the same line does its
- job. In Lisp mode and related modes, the `M-;'
- (`indent-for-comment') command automatically inserts such a `;' in
- the right place, or aligns such a comment if it is already present.
-
- This and following examples are taken from the Emacs sources.
-
- (setq base-version-list ; there was a base
- (assoc (substring fn 0 start-vn) ; version to which
- file-version-assoc-list)) ; this looks like
- ; a subversion
-
-`;;'
- Comments that start with two semicolons, `;;', should be aligned to
- the same level of indentation as the code. Such comments usually
- describe the purpose of the following lines or the state of the
- program at that point. For example:
-
- (prog1 (setq auto-fill-function
- ...
- ...
- ;; update modeline
- (redraw-modeline)))
-
- Every function that has no documentation string (because it is use
- only internally within the package it belongs to), should have
- instead a two-semicolon comment right before the function,
- explaining what the function does and how to call it properly.
- Explain precisely what each argument means and how the function
- interprets its possible values.
-
-`;;;'
- Comments that start with three semicolons, `;;;', should start at
- the left margin. Such comments are used outside function
- definitions to make general statements explaining the design
- principles of the program. For example:
-
- ;;; This Lisp code is run in XEmacs
- ;;; when it is to operate as a server
- ;;; for other processes.
-
- Another use for triple-semicolon comments is for commenting out
- lines within a function. We use triple-semicolons for this
- precisely so that they remain at the left margin.
-
- (defun foo (a)
- ;;; This is no longer necessary.
- ;;; (force-mode-line-update)
- (message "Finished with %s" a))
-
-`;;;;'
- Comments that start with four semicolons, `;;;;', should be aligned
- to the left margin and are used for headings of major sections of a
- program. For example:
-
- ;;;; The kill ring
-
-The indentation commands of the Lisp modes in XEmacs, such as `M-;'
-(`indent-for-comment') and <TAB> (`lisp-indent-line') automatically
-indent comments according to these conventions, depending on the number
-of semicolons. *Note Manipulating Comments: (emacs)Comments.
-
-\1f
-File: lispref.info, Node: Library Headers, Prev: Comment Tips, Up: Tips
-
-Conventional Headers for XEmacs Libraries
-=========================================
-
- XEmacs has conventions for using special comments in Lisp libraries
-to divide them into sections and give information such as who wrote
-them. This section explains these conventions. First, an example:
-
- ;;; lisp-mnt.el --- minor mode for Emacs Lisp maintainers
-
- ;; Copyright (C) 1992 Free Software Foundation, Inc.
-
- ;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
- ;; Maintainer: Eric S. Raymond <esr@snark.thyrsus.com>
- ;; Created: 14 Jul 1992
- ;; Version: 1.2
- ;; Keywords: docs
-
- ;; This file is part of XEmacs.
- COPYING PERMISSIONS...
-
- The very first line should have this format:
-
- ;;; FILENAME --- DESCRIPTION
-
-The description should be complete in one line.
-
- After the copyright notice come several "header comment" lines, each
-beginning with `;; HEADER-NAME:'. Here is a table of the conventional
-possibilities for HEADER-NAME:
-
-`Author'
- This line states the name and net address of at least the principal
- author of the library.
-
- If there are multiple authors, you can list them on continuation
- lines led by `;;' and a tab character, like this:
-
- ;; Author: Ashwin Ram <Ram-Ashwin@cs.yale.edu>
- ;; Dave Sill <de5@ornl.gov>
- ;; Dave Brennan <brennan@hal.com>
- ;; Eric Raymond <esr@snark.thyrsus.com>
-
-`Maintainer'
- This line should contain a single name/address as in the Author
- line, or an address only, or the string `FSF'. If there is no
- maintainer line, the person(s) in the Author field are presumed to
- be the maintainers. The example above is mildly bogus because the
- maintainer line is redundant.
-
- The idea behind the `Author' and `Maintainer' lines is to make
- possible a Lisp function to "send mail to the maintainer" without
- having to mine the name out by hand.
-
- Be sure to surround the network address with `<...>' if you
- include the person's full name as well as the network address.
-
-`Created'
- This optional line gives the original creation date of the file.
- For historical interest only.
-
-`Version'
- If you wish to record version numbers for the individual Lisp
- program, put them in this line.
-
-`Adapted-By'
- In this header line, place the name of the person who adapted the
- library for installation (to make it fit the style conventions, for
- example).
-
-`Keywords'
- This line lists keywords for the `finder-by-keyword' help command.
- This field is important; it's how people will find your package
- when they're looking for things by topic area. To separate the
- keywords, you can use spaces, commas, or both.
-
- Just about every Lisp library ought to have the `Author' and
-`Keywords' header comment lines. Use the others if they are
-appropriate. You can also put in header lines with other header
-names--they have no standard meanings, so they can't do any harm.
-
- We use additional stylized comments to subdivide the contents of the
-library file. Here is a table of them:
-
-`;;; Commentary:'
- This begins introductory comments that explain how the library
- works. It should come right after the copying permissions.
-
-`;;; Change log:'
- This begins change log information stored in the library file (if
- you store the change history there). For most of the Lisp files
- distributed with XEmacs, the change history is kept in the file
- `ChangeLog' and not in the source file at all; these files do not
- have a `;;; Change log:' line.
-
-`;;; Code:'
- This begins the actual code of the program.
-
-`;;; FILENAME ends here'
- This is the "footer line"; it appears at the very end of the file.
- Its purpose is to enable people to detect truncated versions of
- the file from the lack of a footer line.
-
-\1f
-File: lispref.info, Node: Building XEmacs and Object Allocation, Next: Standard Errors, Prev: Tips, Up: Top
-
-Building XEmacs; Allocation of Objects
-**************************************
-
- This chapter describes how the runnable XEmacs executable is dumped
-with the preloaded Lisp libraries in it and how storage is allocated.
-
- There is an entire separate document, the `XEmacs Internals Manual',
-devoted to the internals of XEmacs from the perspective of the C
-programmer. It contains much more detailed information about the build
-process, the allocation and garbage-collection process, and other
-aspects related to the internals of XEmacs.
-
-* Menu:
-
-* Building XEmacs:: How to preload Lisp libraries into XEmacs.
-* Pure Storage:: A kludge to make preloaded Lisp functions sharable.
-* Garbage Collection:: Reclaiming space for Lisp objects no longer used.
-
projects / chise / xemacs-chise.git.1 / blobdiff