stringproc

`adjust_external_format` () — Function

Prints information about the current external format of the Lisp reader and in case the external format encoding differs from the encoding of the application which runs Maxima adjust_external_format tries to adjust the encoding or prints some help or instruction. adjust_external_format returns true when the external format has been changed and false otherwise.

Functions like cint, unicode, octets_005fto_005fstring and string_005fto_005foctets need UTF-8 as the external format of the Lisp reader to work properly over the full range of Unicode characters.

Examples (Maxima on Windows, March 2016): Using adjust_external_format when the default external format is not equal to the encoding provided by the application.

Command line Maxima

In case a terminal session is preferred it is recommended to use Maxima compiled with SBCL. Here Unicode support is provided by default and calls to adjust_external_format are unnecessary.

If Maxima is compiled with CLISP or GCL it is recommended to change the terminal encoding from CP850 to CP1252. adjust_external_format prints some help.

CCL reads UTF-8 while the terminal input is CP850 by default. CP1252 is not supported by CCL. adjust_external_format prints instructions for changing the terminal encoding and external format both to iso-8859-1.

wxMaxima

In wxMaxima SBCL reads CP1252 by default but the input from the application is UTF-8 encoded. Adjustment is needed.

Calling adjust_external_format and restarting Maxima permanently changes the default external format to UTF-8.

(%i1)adjust_external_format();
The line
(setf sb-impl::*default-external-format* :utf-8)
has been appended to the init file
C:/Users/Username/.sbclrc
Please restart Maxima to set the external format to UTF-8.
(%i1) false

Restarting Maxima.

(%i1) adjust_external_format();
The external format is currently UTF-8
and has not been changed.
(%i1) false

See also: cint, unicode, octets_to_string, string_to_octets.

`alphacharp` (char) — Function

Returns true if char is an alphabetic character.

To identify a non-US-ASCII character as an alphabetic character the underlying Lisp must provide full Unicode support. E.g. a German umlaut is detected as an alphabetic character with SBCL in GNU/Linux but not with GCL. (In Windows Maxima, when compiled with SBCL, must be set to UTF-8. See adjust_005fexternal_005fformat for more.)

Example: Examination of non-US-ASCII characters.

The underlying Lisp (SBCL, GNU/Linux) is able to convert the typed character into a Lisp character and to examine.

(%i1) alphacharp("u");
(%o1)                          true

In GCL this is not possible. An error break occurs.

(%i1) alphacharp("u");
(%o1)                          true
(%i2) alphacharp("u");

package stringproc: u cannot be converted into a Lisp character.
 -- an error.

`alphanumericp` (char) — Function

Returns true if char is an alphabetic character or a digit (only corresponding US-ASCII characters are regarded as digits).

Note: See remarks on alphacharp.

See also: alphacharp.

`ascii` (int) — Function

Returns the US-ASCII character corresponding to the integer int which has to be less than 128.

See unicode for converting code points larger than 127.

Examples:

(%i1) for n from 0 thru 127 do ( 
        ch: ascii(n), 
        if alphacharp(ch) then sprint(ch),
        if n = 96 then newline() )$
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
a b c d e f g h i j k l m n o p q r s t u v w x y z

`cequal` (char_1, char_2) — Function

Returns true if char_1 and char_2 are the same character.

`cequalignore` (char_1, char_2) — Function

Like cequal but ignores case which is only possible for non-US-ASCII characters when the underlying Lisp is able to recognize a character as an alphabetic character. See remarks on alphacharp.

See also: alphacharp.

`cgreaterp` (char_1, char_2) — Function

Returns true if the code point of char_1 is greater than the code point of char_2.

`cgreaterpignore` (char_1, char_2) — Function

Like cgreaterp but ignores case which is only possible for non-US-ASCII characters when the underlying Lisp is able to recognize a character as an alphabetic character. See remarks on alphacharp.

See also: alphacharp.

`charat` (string, n) — Function

Returns the n-th character of string. The first character in string is returned with n = 1.

(%i1) charat("Lisp",1);
(%o1)                           L
(%i2) charlist("Lisp")[1];
(%o2)                           L

`charlist` (string) — Function

Returns the list of all characters in string.

(%i1) charlist("Lisp");
(%o1)                     [L, i, s, p]

`charp` (obj) — Function

Returns true if obj is a Maxima-character. See introduction for example.

`cint` (char) — Function

Returns the Unicode code point of char which must be a Maxima character, i.e. a string of length 1.

Examples: The hexadecimal code point of some characters (Maxima with SBCL on GNU/Linux).

(%i1) obase: 16.$
(%i2) map(cint, ["$","GBP","EUR"]);
(%o2)                           [24, 0A3, 20AC]

Warning: It is not possible to enter characters corresponding to code points larger than 16 bit in wxMaxima with SBCL on Windows when the external format has not been set to UTF-8. See adjust_005fexternal_005fformat.

CMUCL doesn’t process these characters as one character. cint then returns false.

Converting a character to a code point via UTF-8-octets may serve as a workaround:

utf8_to_unicode(string_to_octets(character));

See utf8_005fto_005funicode, string_005fto_005foctets.

See also: adjust_external_format, utf8_to_unicode, string_to_octets.

`clessp` (char_1, char_2) — Function

Returns true if the code point of char_1 is less than the code point of char_2.

`clesspignore` (char_1, char_2) — Function

Like clessp but ignores case which is only possible for non-US-ASCII characters when the underlying Lisp is able to recognize a character as an alphabetic character. See remarks on alphacharp.

See also: alphacharp.

`close` (stream) — Function

Closes stream and returns true if stream had been open.

`constituent` (char) — Function

Returns true if char is a graphic character but not a space character. A graphic character is a character one can see, plus the space character. (constituent is defined by Paul Graham. See Paul Graham, ANSI Common Lisp, 1996, page 67.)

(%i1) for n from 0 thru 255 do ( 
tmp: ascii(n), if constituent(tmp) then sprint(tmp) )$
! " #  %  ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ A B
C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ` a b c
d e f g h i j k l m n o p q r s t u v w x y z { | } ~

`digitcharp` (char) — Function

Returns true if char is a digit where only the corresponding US-ASCII-character is regarded as a digit.

`eval_string` (str) — Function

Parse the string str as a Maxima expression and evaluate it. The string str may or may not have a terminator (dollar sign $ or semicolon ;). Only the first expression is parsed and evaluated, if there is more than one.

Complain if str is not a string.

Examples:

(%i1) eval_string ("foo: 42; bar: foo^2 + baz");
(%o1)                       42
(%i2) eval_string ("(foo: 42, bar: foo^2 + baz)");
(%o2)                   baz + 1764

See also parse_005fstring and eval_005fstring_005flisp.

See also: parse_string, eval_string_lisp.

`flength` (stream) — Function

stream has to be an open stream from or to a file. flength then returns the number of bytes which are currently present in this file.

Example: See writebyte .

`flush_output` (stream) — Function

Flushes stream where stream has to be an output stream to a file.

Example: See writebyte .

`fposition` (stream) — Function

Returns the current position in stream, if pos is not used. If pos is used, fposition sets the position in stream. stream has to be a stream from or to a file and pos has to be a positive number.

Positions in data streams are like in strings or lists 1-indexed, i.e. the first element in stream is in position 1.

`freshline` () — Function

Writes a new line to the standard output stream if the position is not at the beginning of a line and returns true. Using the optional argument stream the new line is written to that stream. There are some cases, where freshline() does not work as expected.

`get_output_stream_string` (stream) — Function

Returns a string containing all the characters currently present in stream which must be an open string-output stream. The returned characters are removed from stream.

Example: See make_005fstring_005foutput_005fstream .

`lowercasep` (char) — Function

Returns true if char is a lowercase character.

Note: See remarks on alphacharp.

See also: alphacharp.

`make_string_input_stream` (string) — Function

Returns an input stream which contains parts of string and an end of file. Without optional arguments the stream contains the entire string and is positioned in front of the first character. start and end define the substring contained in the stream. The first character is available at position 1.

(%i1) istream : make_string_input_stream("text", 1, 4);
(%o1)              #<string-input stream from "text">
(%i2) (while (c : readchar(istream)) # false do sprint(c), newline())$
t e x 
(%i3) close(istream)$

`make_string_output_stream` () — Function

Returns an output stream that accepts characters. Characters currently present in this stream can be retrieved by get_005foutput_005fstream_005fstring.

(%i1) ostream : make_string_output_stream();
(%o1)               #<string-output stream 09622ea0>
(%i2) printf(ostream, "foo")$

(%i3) printf(ostream, "bar")$

(%i4) string : get_output_stream_string(ostream);
(%o4)                            foobar
(%i5) printf(ostream, "baz")$

(%i6) string : get_output_stream_string(ostream);
(%o6)                              baz
(%i7) close(ostream)$

`newline` () — Function

Writes a new line to the standard output stream. Using the optional argument stream the new line is written to that stream. There are some cases, where newline() does not work as expected.

See sprint for an example of using newline().

`opena` (file) — Function

Returns a character output stream to file. If an existing file is opened, opena appends elements at the end of file.

For binary output see Functions-and-Variables-for-binary-input-and-output .

See also: Functions-and-Variables-for-binary-input-and-output.

`openr` (file) — Function

Returns a character input stream to file. openr assumes that file already exists. If reading the file results in a lisp error about its encoding passing the correct string as the argument encoding might help. The available encodings and their names depend on the lisp being used. For sbcl a list of suitable strings can be found at http://www.sbcl.org/manual/#External-Formats.

For binary input see Functions-and-Variables-for-binary-input-and-output . See also close and openw.

(%i1) istream : openr("data.txt","EUC-JP");
(%o1)     #<FD-STREAM for "file /home/gunter/data.txt" {10099A3AE3}>
(%i2) close(istream);
(%o2)                                true

See also: Functions-and-Variables-for-binary-input-and-output, close, openw.

`openw` (file) — Function

Returns a character output stream to file. If file does not exist, it will be created. If an existing file is opened, openw destructively modifies file.

For binary output see Functions-and-Variables-for-binary-input-and-output .

`parse_string` (str) — Function

Parse the string str as a Maxima expression (do not evaluate it). The string str may or may not have a terminator (dollar sign $ or semicolon ;). Only the first expression is parsed, if there is more than one.

Complain if str is not a string.

Examples:

(%i1) parse_string ("foo: 42; bar: foo^2 + baz");
(%o1)                    foo : 42
(%i2) parse_string ("(foo: 42, bar: foo^2 + baz)");
                                   2
(%o2)          (foo : 42, bar : foo  + baz)

`printf` (dest, string) — Function

Produces formatted output by outputting the characters of control-string string and observing that a tilde introduces a directive. The character after the tilde, possibly preceded by prefix parameters and modifiers, specifies what kind of formatting is desired. Most directives use one or more elements of the arguments expr_1, …, expr_n to create their output.

If dest is a stream or true, then printf returns false. Otherwise, printf returns a string containing the output. By default the streams stdin, stdout and stderr are defined. If Maxima is running as a network client (which is the normal case if Maxima is communicating with a graphical user interface, which must be the server) setup-client will define old_stdout and old_stderr, too.

printf provides the Common Lisp function format in Maxima. The following example illustrates the general relation between these two functions.

(%i1) printf(true, "R~dD~d~%", 2, 2);
R2D2
(%o1)                                false
(%i2) :lisp (format t "R~dD~d~%" 2 2)
R2D2
NIL

The following description is limited to a rough sketch of the possibilities of printf. The Lisp function format is described in detail in many reference books. Of good help is e.g. the free available online-manual “Common Lisp the Language” by Guy L. Steele. See chapter 22.3.3 there.

In addition, printf recognizes two format directives which are not known to Lisp format. The format directive ~m indicates Maxima pretty printer output. The format directive ~h indicates a bigfloat number.

~%       new line
   ~&       fresh line
   ~t       tab
   ~$       monetary
   ~d       decimal integer
   ~b       binary integer
   ~o       octal integer
   ~x       hexadecimal integer
   ~br      base-b integer
   ~r       spell an integer
   ~p       plural
   ~f       floating point
   ~e       scientific notation
   ~g       ~f or ~e, depending upon magnitude
   ~h       bigfloat
   ~a       uses Maxima function string
   ~m       Maxima pretty printer output
   ~s       like ~a, but output enclosed in "double quotes"
   ~~       ~
   ~<       justification, ~> terminates
   ~(       case conversion, ~) terminates 
   ~[       selection, ~] terminates 
   ~{       iteration, ~} terminates

Note that the directive ~* is not supported.

If dest is a stream or true, then printf returns false. Otherwise, printf returns a string containing the output.

(%i1) printf( false, "~a ~a ~4f ~a ~@r", 
              "String",sym,bound,sqrt(12),144), bound = 1.234;
(%o1)                 String sym 1.23 2*sqrt(3) CXLIV
(%i2) printf( false,"~{~a ~}",["one",2,"THREE"] );
(%o2)                          one 2 THREE 
(%i3) printf(true,"~{~{~9,1f ~}~%~}",mat ),
          mat = args(matrix([1.1,2,3.33],[4,5,6],[7,8.88,9]))$
      1.1       2.0       3.3 
      4.0       5.0       6.0 
      7.0       8.9       9.0 
(%i4) control: "~:(~r~) bird~p ~[is~;are~] singing."$
(%i5) printf( false,control, n,n,if n=1 then 1 else 2 ), n=2;
(%o5)                    Two birds are singing.

The directive ~h has been introduced to handle bigfloats.

~w,d,e,x,o,p@H
 w : width
 d : decimal digits behind floating point
 e : minimal exponent digits
 x : preferred exponent
 o : overflow character
 p : padding character
 @ : display sign for positive numbers

(%i1) fpprec : 1000$
(%i2) printf(true, "|~h|~%", 2.b0^-64)$
|0.0000000000000000000542101086242752217003726400434970855712890625|
(%i3) fpprec : 26$
(%i4) printf(true, "|~h|~%", sqrt(2))$
|1.4142135623730950488016887|
(%i5) fpprec : 24$
(%i6) printf(true, "|~h|~%", sqrt(2))$
|1.41421356237309504880169|
(%i7) printf(true, "|~28h|~%", sqrt(2))$
|   1.41421356237309504880169|
(%i8) printf(true, "|~28,,,,,'*h|~%", sqrt(2))$
|***1.41421356237309504880169|
(%i9) printf(true, "|~,18h|~%", sqrt(2))$
|1.414213562373095049|
(%i10) printf(true, "|~,,,-3h|~%", sqrt(2))$
|1414.21356237309504880169b-3|
(%i11) printf(true, "|~,,2,-3h|~%", sqrt(2))$
|1414.21356237309504880169b-03|
(%i12) printf(true, "|~20h|~%", sqrt(2))$
|1.41421356237309504880169|
(%i13) printf(true, "|~20,,,,'+h|~%", sqrt(2))$
|++++++++++++++++++++|

For conversion of objects to strings also see concat, sconcat, string and simplode.

See also: concat, sconcat, string, simplode.

`readbyte` (stream) — Function

Removes and returns the first byte in stream which must be a binary input stream. If the end of file is encountered readbyte returns false.

Example: Read the first 16 bytes from a file encrypted with AES in OpenSSL.

(%i1) ibase: obase: 16.$

(%i2) in: openr_binary("msg.bin");
(%o2)                       #<input stream msg.bin>
(%i3) (L:[],  thru 16. do push(readbyte(in), L),  L:reverse(L));
(%o3) [53, 61, 6C, 74, 65, 64, 5F, 5F, 88, 56, 0DE, 8A, 74, 0FD,
       0AD, 0F0]
(%i4) close(in);
(%o4)                                true
(%i5) map(ascii, rest(L,-8));
(%o5)                      [S, a, l, t, e, d, _, _]
(%i6) salt: octets_to_number(rest(L,8));
(%o6)                          8856de8a74fdadf0

`readchar` (stream) — Function

Removes and returns the first character in stream. If the end of file is encountered readchar returns false.

Example: See make_005fstring_005finput_005fstream.

`readline` (stream) — Function

Returns a string containing all characters starting at the current position in stream up to the end of the line or false if the end of the file is encountered.

`scopy` (string) — Function

Returns a copy of string as a new string.

`sdowncase` (string) — Function

Like supcase but uppercase characters are converted to lowercase.

`sequal` (string_1, string_2) — Function

Returns true if string_1 and string_2 contain the same sequence of characters.

`sequalignore` (string_1, string_2) — Function

Like sequal but ignores case which is only possible for non-US-ASCII characters when the underlying Lisp is able to recognize a character as an alphabetic character. See remarks on alphacharp.

See also: alphacharp.

`sexplode` (string) — Function

sexplode is an alias for function charlist.

`simplode` (list) — Function

simplode takes a list of expressions and concatenates them into a string. If no delimiter delim is specified, simplode uses no delimiter. delim can be any string.

See also concat, sconcat, string and printf.

Examples:

(%i1) simplode(["xx[",3,"]:",expand((x+y)^3)]);
(%o1)             xx[3]:y^3+3*x*y^2+3*x^2*y+x^3
(%i2) simplode( sexplode("stars")," * " );
(%o2)                   s * t * a * r * s
(%i3) simplode( ["One","more","coffee."]," " );
(%o3)                   One more coffee.

See also: concat, sconcat, string, printf.

`sinsert` (seq, string, pos) — Function

Returns a string that is a concatenation of substring(string, 1, pos-1), the string seq and substring (string, pos). Note that the first character in string is in position 1.

Examples:

(%i1) s: "A submarine."$
(%i2) concat( substring(s,1,3),"yellow ",substring(s,3) );
(%o2)                  A yellow submarine.
(%i3) sinsert("hollow ",s,3);
(%o3)                  A hollow submarine.

`sinvertcase` (string) — Function

Returns string except that each character from position start to end is inverted. If end is not given, all characters from start to the end of string are replaced.

Examples:

(%i1) sinvertcase("sInvertCase");
(%o1)                      SiNVERTcASE

`slength` (string) — Function

Returns the number of characters in string.

`smake` (num, char) — Function

Returns a new string with a number of num characters char.

Example:

(%i1) smake(3,"w");
(%o1)                          www

`smismatch` (string_1, string_2) — Function

Returns the position of the first character of string_1 at which string_1 and string_2 differ or false. Default test function for matching is sequal. If smismatch should ignore case, use sequalignore as test.

Example:

(%i1) smismatch("seven","seventh");
(%o1)                           6

`space` — Variable

The space character.

`split` (string) — Function

Returns the list of all tokens in string. Each token is an unparsed string. split uses delim as delimiter. If delim is not given, the space character is the default delimiter. multiple is a boolean variable with true by default. Multiple delimiters are read as one. This is useful if tabs are saved as multiple space characters. If multiple is set to false, each delimiter is noted.

Examples:

(%i1) split("1.2   2.3   3.4   4.5");
(%o1)                 [1.2, 2.3, 3.4, 4.5]
(%i2) split("first;;third;fourth",";",false);
(%o2)               [first, , third, fourth]

`sposition` (char, string) — Function

Returns the position of the first character in string which matches char. The first character in string is in position 1. For matching characters ignoring case see ssearch.

`sprint` (expr_1, …, expr_n) — Function

Evaluates and displays its arguments one after the other ‘on a line’ starting at the leftmost position. The expressions are printed with a space character right next to the number, and it disregards line length.
newline() might be used for line breaking.

Example: Sequential printing with sprint. Creating a new line with newline().

(%i1) for n:0 thru 19 do sprint(fib(n))$
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181
(%i2) for n:0 thru 22 do ( 
         sprint(fib(n)), 
         if mod(n,10) = 9 then newline() )$
0 1 1 2 3 5 8 13 21 34 
55 89 144 233 377 610 987 1597 2584 4181 
6765 10946 17711

`sremove` (seq, string) — Function

Returns a string like string but without all substrings matching seq. Default test function for matching is sequal. If sremove should ignore case while searching for seq, use sequalignore as test. Use start and end to limit searching. Note that the first character in string is in position 1.

Examples:

(%i1) sremove("n't","I don't like coffee.");
(%o1)                   I do like coffee.
(%i2) sremove ("DO ",%,'sequalignore);
(%o2)                    I like coffee.

`sremovefirst` (seq, string) — Function

Like sremove except that only the first substring that matches seq is removed.

`sreverse` (string) — Function

Returns a string with all the characters of string in reverse order.

`ssearch` (seq, string) — Function

Returns the position of the first substring of string that matches the string seq. Default test function for matching is sequal. If ssearch should ignore case, use sequalignore as test. Use start and end to limit searching. Note that the first character in string is in position 1.

Example:

(%i1) ssearch("~s","~{~S ~}~%",'sequalignore);
(%o1)                                  4

`ssort` (string) — Function

Returns a string that contains all characters from string in an order such there are no two successive characters c and d such that test (c, d) is false and test (d, c) is true. Default test function for sorting is clessp. The set of test functions is {clessp, clesspignore, cgreaterp, cgreaterpignore, cequal, cequalignore}.

Examples:

(%i1) ssort("I don't like Mondays.");
(%o1)                    '.IMaddeiklnnoosty
(%i2) ssort("I don't like Mondays.",'cgreaterpignore);
(%o2)                 ytsoonnMlkIiedda.'

`ssubst` (new, old, string) — Function

Returns a string like string except that all substrings matching old are replaced by new. old and new need not to be of the same length. Default test function for matching is sequal. If ssubst should ignore case while searching for old, use sequalignore as test. Use start and end to limit searching. Note that the first character in string is in position 1.

Examples:

(%i1) ssubst("like","hate","I hate Thai food. I hate green tea.");
(%o1)          I like Thai food. I like green tea.
(%i2) ssubst("Indian","thai",%,'sequalignore,8,12);
(%o2)         I like Indian food. I like green tea.

`ssubstfirst` (new, old, string) — Function

Like subst except that only the first substring that matches old is replaced.

`strim` (seq, string) — Function

Returns a string like string, but with all characters that appear in seq removed from both ends.

Examples:

(%i1) "/* comment */"$
(%i2) strim(" /*",%);
(%o2)                        comment
(%i3) slength(%);
(%o3)                           7

`striml` (seq, string) — Function

Like strim except that only the left end of string is trimmed.

`strimr` (seq, string) — Function

Like strim except that only the right end of string is trimmed.

`stringp` (obj) — Function

Returns true if obj is a string. See introduction for example.

`substring` (string, start) — Function

Returns the substring of string beginning at position start and ending at position end. The character at position end is not included. If end is not given, the substring contains the rest of the string. Note that the first character in string is in position 1.

Examples:

(%i1) substring("substring",4);
(%o1)                        string
(%i2) substring(%,4,6);
(%o2)                          in

`supcase` (string) — Function

Returns string except that lowercase characters from position start to end are replaced by the corresponding uppercase ones. If end is not given, all lowercase characters from start to the end of string are replaced.

Example:

(%i1) supcase("english",1,2);
(%o1)                        English

`tab` — Variable

The tab character.

`tokens` (string) — Function

Returns a list of tokens, which have been extracted from string. The tokens are substrings whose characters satisfy a certain test function. If test is not given, constituent is used as the default test. {constituent, alphacharp, digitcharp, lowercasep, uppercasep, charp, characterp, alphanumericp} is the set of test functions. (The Lisp-version of tokens is written by Paul Graham. ANSI Common Lisp, 1996, page 67.)

Examples:

(%i1) tokens("24 October 2005");
(%o1)                  [24, October, 2005]
(%i2) tokens("05-10-24",'digitcharp);
(%o2)                     [05, 10, 24]
(%i3) map(parse_string,%);
(%o3)                      [5, 10, 24]

`unicode` (arg) — Function

Returns the character defined by arg which might be a Unicode code point or a name string if the underlying Lisp provides full Unicode support.

Example: Characters defined by hexadecimal code points (Maxima with SBCL on GNU/Linux).

(%i1) ibase: 16.$
(%i2) map(unicode, [24, 0A3, 20AC]);
(%o2)                            [$, GBP, EUR]

Warning: In wxMaxima with SBCL on Windows it is not possible to convert code points larger than 16 bit to characters when the external format has not been set to UTF-8. See adjust_005fexternal_005fformat for more information.

CMUCL doesn’t process code points larger than 16 bit. In these cases unicode returns false.

Converting a code point to a character via UTF-8 octets may serve as a workaround:

octets_to_string(unicode_to_utf8(code_point));

See octets_005fto_005fstring, unicode_005fto_005futf8.

In case the underlying Lisp provides full Unicode support the character might be specified by its name. The following is possible in ECL, CLISP and SBCL, where in SBCL on Windows the external format has to be set to UTF-8. unicode(name) is supported by CMUCL too but again limited to 16 bit characters.

The string argument to unicode is basically the same string returned by printf using the “~@c” specifier. But as shown below the prefix “#" must be omitted. Underlines might be replaced by spaces and uppercase letters by lowercase ones.

Example (continued): Characters defined by names (Maxima with SBCL on GNU/Linux).

(%i3) printf(false, "~@c", unicode(0DF));
(%o3)                    #\LATIN_SMALL_LETTER_SHARP_S
(%i4) unicode("LATIN_SMALL_LETTER_SHARP_S");
(%o4)                                  ß
(%i5) unicode("Latin small letter sharp s");
(%o5)                                  ß

See also: adjust_external_format, octets_to_string, unicode_to_utf8.

`unicode_to_utf8` (code_point) — Function

Returns a list containing the UTF-8 code corresponding to the Unicode code_point.

Examples: Converting Unicode code points to UTF-8 and vice versa.

(%i1) ibase: obase: 16.$
(%i2) map(cint, ["$","GBP","EUR"]);
(%o2)                           [24, 0A3, 20AC]
(%i3) map(unicode_to_utf8, %);
(%o3)                 [[24], [0C2, 0A3], [0E2, 82, 0AC]]
(%i4) map(utf8_to_unicode, %);
(%o4)                           [24, 0A3, 20AC]

`uppercasep` (char) — Function

Returns true if char is an uppercase character.

Note: See remarks on alphacharp.

See also: alphacharp.

`us_ascii_only` — Variable

This option variable affects Maxima when the character encoding provided by the application which runs Maxima is UTF-8 but the external format of the Lisp reader is not equal to UTF-8.

On GNU/Linux this is true when Maxima is built with GCL and on Windows in wxMaxima with GCL- and SBCL-builds. With SBCL it is recommended to change the external format to UTF-8. Setting us_ascii_only is unnecessary then. See adjust_005fexternal_005fformat for details.

us_ascii_only is false by default. Maxima itself then (i.e. in the above described situation) parses the UTF-8 encoding.

When us_ascii_only is set to true it is assumed that all strings used as arguments to string processing functions do not contain Non-US-ASCII characters. Given that promise, Maxima avoids parsing UTF-8 and strings can be processed more efficiently.

`utf8_to_unicode` (list) — Function

Returns a Unicode code point corresponding to the list which must contain the UTF-8 encoding of a single character.

Examples: See unicode_005fto_005futf8.

`writebyte` (byte, stream) — Function

Writes byte to stream which must be a binary output stream. writebyte returns byte.

Example: Write some bytes to a binary file output stream. In this example all bytes correspond to printable characters and are printed by printfile. The bytes remain in the stream until flush_output or close have been called.

(%i1) ibase: obase: 16.$

(%i2) bytes: map(cint, charlist("GNU/Linux"));
(%o2)                [47, 4E, 55, 2F, 4C, 69, 6E, 75, 78]
(%i3) out: openw_binary("test.bin");
(%o3)                      #<output stream test.bin>
(%i4) for i thru 3 do writebyte(bytes[i], out);
(%o4)                                done
(%i5) printfile("test.bin")$

(%i6) flength(out);
(%o6)                                  0
(%i7) flush_output(out);
(%o7)                                true
(%i8) flength(out);
(%o8)                                  3
(%i9) printfile("test.bin")$
GNU
(%i0A) for b in rest(bytes,3) do writebyte(b, out);
(%o0A)                               done
(%i0B) close(out);
(%o0B)                               true
(%i0C) printfile("test.bin")$
GNU/Linux

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