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string-concatenate-reverse[/shared]. (Reverse/Append): Document the parameter `end' to string-concatenate-reverse.
1093 lines
37 KiB
Text
1093 lines
37 KiB
Text
@node SRFI-13/14
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@chapter SRFI-13 and SRFI-14
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This chapter documents the SRFI-13/14 library, which provides the string
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utility procedures defined in SRFI-13 and the character-set procedures
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defined in SRFI-14 for Guile.
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@menu
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* Introduction:: What is this all about?
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* Loading SRFI-13/14:: Loading the module into a running Guile.
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* String Functions:: Available string processing procedures.
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* Character-set Procedures:: Procedures for manipulating character sets.
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@end menu
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@c ===================================================================
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@node Introduction
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@section Introduction
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The SRFI-13/14 library is a shared library which provides the procedures
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defined in SRFI-13 (string library) and the procedures defined in
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SRFI-14 (character-set library). You should also refer to the SRFI
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documents, which provide some details I will not document here.
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If you don't know what SRFI means, and what all the numbers are about,
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you may want to refer to the SRFI home page at
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@url{http://srfi.schemers.org}.
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Note that only the procedures from SRFI-13 are documented here which are
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not already contained in Guile. For procedures not documented here
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please refer to the relevant chapters in the Guile Reference Manual, for
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example the documentation of strings and string procedures (REFFIXME).
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The SRFI-14 procedures are documented completely.
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@menu
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* What can be done:: What is possible with SRFI-13/14
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* What cannot be done:: and what is not?
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@end menu
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@c ===================================================================
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@node What can be done
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@subsection What can be done
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All of the procedures defined in SRFI-13, which are not already included
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in the Guile core library, are implemented in the module @code{(srfi
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srfi-13)}. The procedures which are both in Guile and in SRFI-13, but
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which are slightly extended, have been implemented in this module, and
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the bindings overwrite those in the Guile core.
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All procedures from SRFI-14 (character-set library) are implemented in
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the module @code{(srfi srfi-14)}, as well as the standard variables
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@code{char-set:letter}, @code{char-set:digit} etc.
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@c ===================================================================
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@node What cannot be done
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@subsection What cannot be done
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The procedures which are defined in the section @emph{Low-level
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procedures} of SRFI-13 for parsing optional string indices, substring
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specification checking and Knuth-Morris-Pratt-Searching are not
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implemented.
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The procedures @code{string-contains} and @code{string-contains-ci} are
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not implemented very efficiently at the moment. This will be changed as
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soon as possible.
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@c ===================================================================
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@node Loading SRFI-13/14
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@section Loading SRFI-13/14
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When Guile is properly installed, it can be loaded into a running Guile
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by using the @code{(srfi srfi-13)} module.
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@example
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$ guile
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guile> (use-modules (srfi srfi-13))
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guile>
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@end example
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When this step causes any errors, Guile is not properly installed.
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One possible reason is that Guile cannot find either the Scheme module
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file @file{srfi-13.scm}, or it cannot find the shared object file
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@file{libguile-srfi-srfi-13-14.so}. Make sure that the former is in the
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Guile load path and that the latter is either installed in some default
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location like @file{/usr/local/lib} or that the directory it was
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installed to is in your @code{LTDL_LIBRARY_PATH}. The same applies to
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@file{srfi-14.scm}.
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Now you can test whether the SRFI-13 procedures are working by calling
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the @code{string-concatenate} procedure.
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@example
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guile> (string-concatenate '("Hello" " " "World!"))
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"Hello World!"
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@end example
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The same goes for the SRFI-14 module, of course.
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@example
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$ guile
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guile> (use-modules (srfi srfi-14))
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guile> (char-set-union (char-set #\f #\o #\o) (string->char-set "bar"))
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#<charset @{#\a #\b #\f #\o #\r@}>
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guile>
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@end example
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@c ===================================================================
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@node String Functions
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@section String Functions
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In this section, we will describe all procedures defined in SRFI-13
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(string library) and implemented by the module @code{(srfi srfi-13)}.
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Except for the procedures in the section @emph{Low-level procedures} of
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SRFI-13, all string procedures defined there are implemented completely.
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@menu
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* Predicates:: Testing strings.
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* SRFI-13 Constructors:: Constructing strings.
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* SRFI-13 List/String Conversion:: Converstion from/to character lists.
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* SRFI-13 Selection:: Selecting portions from strings.
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* SRFI-13 Modification:: Modifying string in--place.
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* SRFI-13 Comparison:: Comparing strings.
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* Prefixes/Suffixes:: Checking for common pre-/suffixes.
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* Searching:: Searching in strings.
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* Case Mapping:: Changing the case of strings.
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* Reverse/Append:: Append, concatenate and reverse strings.
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* Fold/Unfold/Map:: Fold/Unfold/Map over strings.
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* Replicate/Rotate:: String replication and rotation.
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* Miscellaneous:: Miscellaneous string procedures.
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* Filtering/Deleting:: Deleting characters from strings.
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@end menu
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@c ===================================================================
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@node Predicates
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@subsection Predicates
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In addition to the primitives @code{string?} and @code{string-null?},
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which are already in the Guile core, the string predicates
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@code{string-any} and @code{string-every} are defined by SRFI-13.
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@deffn primitive string-any pred s [start end]
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Check if the predicate @var{pred} is true for any character in
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the string @var{s}, proceeding from left (index @var{start}) to
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right (index @var{end}). If @code{string-any} returns true,
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the returned true value is the one produced by the first
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successful application of @var{pred}.
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@end deffn
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@deffn primitive string-every pred s [start end]
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Check if the predicate @var{pred} is true for every character
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in the string @var{s}, proceeding from left (index @var{start})
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to right (index @var{end}). If @code{string-every} returns
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true, the returned true value is the one produced by the final
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application of @var{pred} to the last character of @var{s}.
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@end deffn
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@c ===================================================================
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@node SRFI-13 Constructors
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@subsection Constructors
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SRFI-13 defines several procedures for constructing new strings. In
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addition to @code{make-string} and @code{string} (available in the Guile
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core library), the procedure @code{string-tabulate} does exist.
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@deffn primitive string-tabulate proc len
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@var{proc} is an integer->char procedure. Construct a string
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of size @var{len} by applying @var{proc} to each index to
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produce the corresponding string element. The order in which
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@var{proc} is applied to the indices is not specified.
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@end deffn
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@c ===================================================================
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@node SRFI-13 List/String Conversion
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@subsection List/String Conversion
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The procedure @code{string->list} is extended by SRFI-13, that is why it
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is included in @code{(srfi srfi-13)}. The other procedures are new.
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The Guile core already contains the procedure @code{list->string} for
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converting a list of characters into a string (REFFIXME).
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@deffn primitive string->list str [start end]
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Convert the string @var{str} into a list of characters.
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@end deffn
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@deffn primitive reverse-list->string chrs
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An efficient implementation of @code{(compose string->list
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reverse)}:
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@smalllisp
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(reverse-list->string '(#\a #\B #\c)) @result{} "cBa"
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@end smalllisp
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@end deffn
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@deffn primitive string-join ls [delimiter grammar]
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Append the string in the string list @var{ls}, using the string
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@var{delim} as a delimiter between the elements of @var{ls}.
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@var{grammar} is a symbol which specifies how the delimiter is
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placed between the strings, and defaults to the symbol
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@code{infix}.
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@table @code
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@item infix
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Insert the separator between list elements. An empty string
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will produce an empty list.
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@item string-infix
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Like @code{infix}, but will raise an error if given the empty
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list.
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@item suffix
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Insert the separator after every list element.
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@item prefix
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Insert the separator before each list element.
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@end table
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@end deffn
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@c ===================================================================
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@node SRFI-13 Selection
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@subsection Selection
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These procedures are called @dfn{selectors}, because they access
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information about the string or select pieces of a given string.
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Additional selector procedures are documented in the Strings section
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(REFFIXME), like @code{string-length} or @code{string-ref}.
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@code{string-copy} is also available in core Guile, but this version
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accepts additional start/end indices.
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@deffn primitive string-copy str [start end]
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Return a freshly allocated copy of the string @var{str}. If
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given, @var{start} and @var{end} delimit the portion of
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@var{str} which is copied.
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@end deffn
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@deffn primitive substring/shared str start [end]
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Like @code{substring}, but the result may share memory with the
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argument @var{str}.
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@end deffn
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@deffn primitive string-copy! target tstart s [start end]
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Copy the sequence of characters from index range [@var{start},
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@var{end}) in string @var{s} to string @var{target}, beginning
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at index @var{tstart}. The characters are copied left-to-right
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or right-to-left as needed -- the copy is guaranteed to work,
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even if @var{target} and @var{s} are the same string. It is an
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error if the copy operation runs off the end of the target
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string.
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@end deffn
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@deffn primitive string-take s n
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@deffnx primitive string-take-right s n
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Return the @var{n} first/last characters of @var{s}.
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@end deffn
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@deffn primitive string-drop s n
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@deffnx primitive string-drop-right s n
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Return all but the first/last @var{n} characters of @var{s}.
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@end deffn
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@deffn primitive string-pad s len [chr start end]
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@deffnx primitive string-pad-right s len [chr start end]
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Take that characters from @var{start} to @var{end} from the
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string @var{s} and return a new string, right(left)-padded by the
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character @var{chr} to length @var{len}. If the resulting
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string is longer than @var{len}, it is truncated on the right (left).
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@end deffn
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@deffn primitive string-trim s [char_pred start end]
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@deffnx primitive string-trim-right s [char_pred start end]
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@deffnx primitive string-trim-both s [char_pred start end]
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Trim @var{s} by skipping over all characters on the left/right/both
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sides of the string that satisfy the parameter @var{char_pred}:
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@itemize @bullet
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@item
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if it is the character @var{ch}, characters equal to
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@var{ch} are trimmed,
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@item
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if it is a procedure @var{pred} characters that
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satisfy @var{pred} are trimmed,
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@item
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if it is a character set, characters in that set are trimmed.
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@end itemize
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If called without a @var{char_pred} argument, all whitespace is
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trimmed.
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@end deffn
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@c ===================================================================
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@node SRFI-13 Modification
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@subsection Modification
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The procedure @code{string-fill!} is extended from R5RS because it
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accepts optional start/end indices. This bindings shadows the procedure
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of the same name in the Guile core. The second modification procedure
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@code{string-set!} is documented in the Strings section (REFFIXME).
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@deffn primitive string-fill! str chr [start end]
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Stores @var{chr} in every element of the given @var{str} and
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returns an unspecified value.
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@end deffn
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@c ===================================================================
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@node SRFI-13 Comparison
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@subsection Comparison
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The procedures in this section are used for comparing strings in
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different ways. The comparison predicates differ from those in R5RS in
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that they do not only return @code{#t} or @code{#f}, but the mismatch
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index in the case of a true return value.
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@code{string-hash} and @code{string-hash-ci} are for calculating hash
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values for strings, useful for implementing fast lookup mechanisms.
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@deffn primitive string-compare s1 s2 proc_lt proc_eq proc_gt [start1 end1 start2 end2]
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@deffnx primitive string-compare-ci s1 s2 proc_lt proc_eq proc_gt [start1 end1 start2 end2]
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Apply @var{proc_lt}, @var{proc_eq}, @var{proc_gt} to the
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mismatch index, depending upon whether @var{s1} is less than,
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equal to, or greater than @var{s2}. The mismatch index is the
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largest index @var{i} such that for every 0 <= @var{j} <
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@var{i}, @var{s1}[@var{j}] = @var{s2}[@var{j}] -- that is,
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@var{i} is the first position that does not match. The
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character comparison is done case-insensitively.
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@end deffn
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@deffn primitive string= s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string<> s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string< s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string> s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string<= s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string>= s1 s2 [start1 end1 start2 end2]
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Compare @var{s1} and @var{s2} and return @code{#f} if the predicate
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fails. Otherwise, the mismatch index is returned (or @var{end1} in the
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case of @code{string=}.
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@end deffn
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@deffn primitive string-ci= s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-ci<> s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-ci< s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-ci> s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-ci<= s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-ci>= s1 s2 [start1 end1 start2 end2]
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Compare @var{s1} and @var{s2} and return @code{#f} if the predicate
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fails. Otherwise, the mismatch index is returned (or @var{end1} in the
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case of @code{string=}. These are the case-insensitive variants.
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@end deffn
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@deffn primitive string-hash s [bound start end]
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@deffnx primitive string-hash-ci s [bound start end]
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Return a hash value of the string @var{s} in the range 0 @dots{}
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@var{bound} - 1. @code{string-hash-ci} is the case-insensitive variant.
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@end deffn
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@c ===================================================================
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@node Prefixes/Suffixes
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@subsection Prefixes/Suffixes
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Using these procedures you can determine whether a given string is a
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prefix or suffix of another string or how long a common prefix/suffix
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is.
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@deffn primitive string-prefix-length s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-prefix-length-ci s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-suffix-length s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-suffix-length-ci s1 s2 [start1 end1 start2 end2]
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Return the length of the longest common prefix/suffix of the two
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strings. @code{string-prefix-length-ci} and
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@code{string-suffix-length-ci} are the case-insensitive variants.
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@end deffn
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@deffn primitive string-prefix? s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-prefix-ci? s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-suffix? s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-suffix-ci? s1 s2 [start1 end1 start2 end2]
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Is @var{s1} a prefix/suffix of @var{s2}. @code{string-prefix-ci?} and
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@code{string-suffix-ci?} are the case-insensitive variants.
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@end deffn
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@c ===================================================================
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@node Searching
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@subsection Searching
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Use these procedures to find out whether a string contains a given
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character or a given substring, or a character from a set of characters.
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@deffn primitive string-index s char_pred [start end]
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@deffnx primitive string-index-right s char_pred [start end]
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Search through the string @var{s} from left to right (right to left),
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returning the index of the first (last) occurence of a character which
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@itemize
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@item
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equals @var{char_pred}, if it is character,
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@item
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satisifies the predicate @var{char_pred}, if it is a
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procedure,
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@item
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is in the set @var{char_pred}, if it is a character set.
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@end itemize
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@end deffn
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@deffn primitive string-skip s char_pred [start end]
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@deffnx primitive string-skip-right s char_pred [start end]
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Search through the string @var{s} from left to right (right to left),
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returning the index of the first (last) occurence of a character which
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@itemize
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@item
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does not equal @var{char_pred}, if it is character,
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@item
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does not satisify the predicate @var{char_pred}, if it is
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a procedure.
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@item
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is not in the set if @var{char_pred} is a character set.
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@end itemize
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@end deffn
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@deffn primitive string-count s char_pred [start end]
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Return the count of the number of characters in the string
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@var{s} which
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@itemize @bullet
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@item
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equals @var{char_pred}, if it is character,
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@item
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satisifies the predicate @var{char_pred}, if it is a procedure.
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@item
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is in the set @var{char_pred}, if it is a character set.
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@end itemize
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@end deffn
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@deffn primitive string-contains s1 s2 [start1 end1 start2 end2]
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@deffnx primitive string-contains-ci s1 s2 [start1 end1 start2 end2]
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Does string @var{s1} contain string @var{s2}? Return the index
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in @var{s1} where @var{s2} occurs as a substring, or false.
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The optional start/end indices restrict the operation to the
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indicated substrings.
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@code{string-contains-ci} is the case-insensitive variant.
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@end deffn
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@c ===================================================================
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|
|
|
@node Case Mapping
|
|
@subsection Alphabetic Case Mapping
|
|
|
|
These procedures convert the alphabetic case of strings. They are
|
|
similar to the procedures in the Guile core, but are extended to handle
|
|
optional start/end indices.
|
|
|
|
@deffn primitive string-upcase s [start end]
|
|
@deffnx primitive string-upcase! s [start end]
|
|
Upcase every character in @var{s}. @code{string-upcase!} is the
|
|
side-effecting variant.
|
|
@end deffn
|
|
|
|
@deffn primitive string-downcase s [start end]
|
|
@deffnx primitive string-downcase! s [start end]
|
|
Downcase every character in @var{s}. @code{string-downcase!} is the
|
|
side--effecting variant.
|
|
@end deffn
|
|
|
|
@deffn primitive string-titlecase s [start end]
|
|
@deffnx primitive string-titlecase! s [start end]
|
|
Upcase every first character in every word in @var{s}, downcase the
|
|
other characters. @code{string-titlecase!} is the side--effecting
|
|
variant.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Reverse/Append
|
|
@subsection Reverse/Append
|
|
|
|
One appending procedure, @code{string-append} is the same in R5RS and in
|
|
SRFI-13, so it is not redefined.
|
|
|
|
@deffn primitive string-reverse str [start end]
|
|
@deffnx primitive string-reverse! str [start end]
|
|
Reverse the string @var{str}. The optional arguments
|
|
@var{start} and @var{end} delimit the region of @var{str} to
|
|
operate on.
|
|
|
|
@code{string-reverse!} modifies the argument string and returns an
|
|
unspecified value.
|
|
@end deffn
|
|
|
|
@deffn primitive string-append/shared ls @dots{}
|
|
Like @code{string-append}, but the result may share memory
|
|
with the argument strings.
|
|
@end deffn
|
|
|
|
@deffn primitive string-concatenate ls
|
|
Append the elements of @var{ls} (which must be strings)
|
|
together into a single string. Guaranteed to return a freshly
|
|
allocated string.
|
|
@end deffn
|
|
|
|
@deffn primitive string-concatenate/shared ls
|
|
Like @code{string-concatenate}, but the result may share memory
|
|
with the strings in the list @var{ls}.
|
|
@end deffn
|
|
|
|
@deffn primitive string-concatenate-reverse ls final_string end
|
|
Without optional arguments, this procedure is equivalent to
|
|
|
|
@smalllisp
|
|
(string-concatenate (reverse ls))
|
|
@end smalllisp
|
|
|
|
If the optional argument @var{final_string} is specified, it is
|
|
consed onto the beginning to @var{ls} before performing the
|
|
list-reverse and string-concatenate operations. If @var{end}
|
|
is given, only the characters of @var{final_string} up to index
|
|
@var{end} are used.
|
|
|
|
Guaranteed to return a freshly allocated string.
|
|
@end deffn
|
|
|
|
@deffn primitive string-concatenate-reverse/shared ls final_string end
|
|
Like @code{string-concatenate-reverse}, but the result may
|
|
share memory with the the strings in the @var{ls} arguments.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Fold/Unfold/Map
|
|
@subsection Fold/Unfold/Map
|
|
|
|
@code{string-map}, @code{string-for-each} etc. are for iterating over
|
|
the characters a string is composed of. The fold and unfold procedures
|
|
are list iterators and constructors.
|
|
|
|
@deffn primitive string-map proc s [start end]
|
|
@var{proc} is a char->char procedure, it is mapped over
|
|
@var{s}. The order in which the procedure is applied to the
|
|
string elements is not specified.
|
|
@end deffn
|
|
|
|
@deffn primitive string-map! proc s [start end]
|
|
@var{proc} is a char->char procedure, it is mapped over
|
|
@var{s}. The order in which the procedure is applied to the
|
|
string elements is not specified. The string @var{s} is
|
|
modified in-place, the return value is not specified.
|
|
@end deffn
|
|
|
|
@deffn primitive string-fold kons knil s [start end]
|
|
@deffnx primitive string-fold-right kons knil s [start end]
|
|
Fold @var{kons} over the characters of @var{s}, with @var{knil} as the
|
|
terminating element, from left to right (or right to left, for
|
|
@code{string-fold-right}). @var{kons} must expect two arguments: The
|
|
actual character and the last result of @var{kons}' application.
|
|
@end deffn
|
|
|
|
@deffn primitive string-unfold p f g seed [base make_final]
|
|
@deffnx primitive string-unfold-right p f g seed [base make_final]
|
|
These are the fundamental string constructors.
|
|
@itemize
|
|
@item @var{g} is used to generate a series of @emph{seed}
|
|
values from the initial @var{seed}: @var{seed}, (@var{g}
|
|
@var{seed}), (@var{g}^2 @var{seed}), (@var{g}^3 @var{seed}),
|
|
@dots{}
|
|
@item @var{p} tells us when to stop -- when it returns true
|
|
when applied to one of these seed values.
|
|
@item @var{f} maps each seed value to the corresponding
|
|
character in the result string. These chars are assembled into the
|
|
string in a left-to-right (right-to-left) order.
|
|
@item @var{base} is the optional initial/leftmost (rightmost)
|
|
portion of the constructed string; it default to the empty string.
|
|
@item @var{make_final} is applied to the terminal seed
|
|
value (on which @var{p} returns true) to produce the final/rightmost
|
|
(leftmost) portion of the constructed string. It defaults to
|
|
@code{(lambda (x) "")}.
|
|
@end itemize
|
|
@end deffn
|
|
|
|
@deffn primitive string-for-each proc s [start end]
|
|
@var{proc} is mapped over @var{s} in left-to-right order. The
|
|
return value is not specified.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Replicate/Rotate
|
|
@subsection Replicate/Rotate
|
|
|
|
These procedures are special substring procedures, which can also be
|
|
used for replicating strings. They are a bit tricky to use, but
|
|
consider this code fragment, which replicates the input string
|
|
@code{"foo"} so often that the resulting string has a length of six.
|
|
|
|
@lisp
|
|
(xsubstring "foo" 0 6)
|
|
@result{}
|
|
"foofoo"
|
|
@end lisp
|
|
|
|
@deffn primitive xsubstring s from [to start end]
|
|
This is the @emph{extended substring} procedure that implements
|
|
replicated copying of a substring of some string.
|
|
|
|
@var{s} is a string, @var{start} and @var{end} are optional
|
|
arguments that demarcate a substring of @var{s}, defaulting to
|
|
0 and the length of @var{s}. Replicate this substring up and
|
|
down index space, in both the positive and negative directions.
|
|
@code{xsubstring} returns the substring of this string
|
|
beginning at index @var{from}, and ending at @var{to}, which
|
|
defaults to @var{from} + (@var{end} - @var{start}).
|
|
@end deffn
|
|
|
|
@deffn primitive string-xcopy! target tstart s sfrom [sto start end]
|
|
Exactly the same as @code{xsubstring}, but the extracted text
|
|
is written into the string @var{target} starting at index
|
|
@var{tstart}. The operation is not defined if @code{(eq?
|
|
@var{target} @var{s})} or these arguments share storage -- you
|
|
cannot copy a string on top of itself.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Miscellaneous
|
|
@subsection Miscellaneous
|
|
|
|
@code{string-replace} is for replacing a portion of a string with
|
|
another string and @code{string-tokenize} splits a string into a list of
|
|
strings, breaking it up at a specified character.
|
|
|
|
@deffn primitive string-replace s1 s2 [start1 end1 start2 end2]
|
|
Return the string @var{s1}, but with the characters
|
|
@var{start1} @dots{} @var{end1} replaced by the characters
|
|
@var{start2} @dots{} @var{end2} from @var{s2}.
|
|
@end deffn
|
|
|
|
@deffn primitive string-tokenize s [token_char start end]
|
|
Split the string @var{s} into a list of substrings, where each
|
|
substring is a maximal non-empty contiguous sequence of
|
|
characters equal to the character @var{token_char}, or
|
|
whitespace, if @var{token_char} is not given. If
|
|
@var{token_char} is a character set, it is used for finding the
|
|
token borders.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Filtering/Deleting
|
|
@subsection Filtering/Deleting
|
|
|
|
@dfn{Filtering} means to remove all characters from a string which do
|
|
not match a given criteria, @dfn{deleting} means the opposite.
|
|
|
|
@deffn primitive string-filter s char_pred [start end]
|
|
Filter the string @var{s}, retaining only those characters that
|
|
satisfy the @var{char_pred} argument. If the argument is a
|
|
procedure, it is applied to each character as a predicate, if
|
|
it is a character, it is tested for equality and if it is a
|
|
character set, it is tested for membership.
|
|
@end deffn
|
|
|
|
@deffn primitive string-delete s char_pred [start end]
|
|
Filter the string @var{s}, retaining only those characters that
|
|
do not satisfy the @var{char_pred} argument. If the argument
|
|
is a procedure, it is applied to each character as a predicate,
|
|
if it is a character, it is tested for equality and if it is a
|
|
character set, it is tested for membership.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Character-set Procedures
|
|
@section Character-set Procedures
|
|
|
|
SRFI-14 defines the data type @dfn{character set}, and also defines a
|
|
lot of procedures for handling this character type, and a few standard
|
|
character sets like whitespace, alphabetic characters and others.
|
|
|
|
@menu
|
|
* Character Set Data Type:: Description of the character set data type.
|
|
* Predicates/Comparison:: Testing character sets.
|
|
* Iterating Over Character Sets:: Iterating over the members of a set.
|
|
* Creating Character Sets:: Creating new character sets.
|
|
* Querying Character Sets:: Extracting information from character sets.
|
|
* Character-Set Algebra:: Set-algebra on character sets.
|
|
* Standard Character Sets:: Variables containg standard character sets.
|
|
@end menu
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Character Set Data Type
|
|
@subsection Character Set Data Type
|
|
|
|
The data type @dfn{charset} implements sets of characters (REFFIXME).
|
|
Because the internal representation of character sets is not visible to
|
|
the user, a lot of procedures for handling them are provided.
|
|
|
|
Character sets can be created, extended, tested for the membership of a
|
|
characters and be compared to other character sets.
|
|
|
|
The Guile implementation of character sets deals with 8-bit characters.
|
|
In the standard variables, only the ASCII part of the character range is
|
|
really used, so that for example @dfn{Umlaute} and other accented
|
|
characters are not considered to be letters. In the future, as Guile
|
|
may get support for international character sets, this will change, so
|
|
don't rely on these ``features''.
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Predicates/Comparison
|
|
@subsection Predicates/Comparison
|
|
|
|
Use these procedures for testing whether an object is a character set,
|
|
or whether several character sets are equal or subsets of each other.
|
|
@code{char-set-hash} can be used for calculating a hash value, maybe for
|
|
usage in fast lookup procedures.
|
|
|
|
@deffn primitive char-set? obj
|
|
Return @code{#t} if @var{obj} is a character set, @code{#f}
|
|
otherwise.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set= cs1 @dots{}
|
|
Return @code{#t} if all given character sets are equal.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set<= cs1 @dots{}
|
|
Return @code{#t} if every character set @var{cs}i is a subset
|
|
of character set @var{cs}i+1.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-hash cs [bound]
|
|
Compute a hash value for the character set @var{cs}. If
|
|
@var{bound} is given and not @code{#f}, it restricts the
|
|
returned value to the range 0 @dots{} @var{bound - 1}.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Iterating Over Character Sets
|
|
@subsection Iterating Over Character Sets
|
|
|
|
Character set cursors are a means for iterating over the members of a
|
|
character sets. After creating a character set cursor with
|
|
@code{char-set-cursor}, a cursor can be dereferenced with
|
|
@code{char-set-ref}, advanced to the next member with
|
|
@code{char-set-cursor-next}. Whether a cursor has passed past the last
|
|
element of the set can be checked with @code{end-of-char-set?}.
|
|
|
|
Additionally, mapping and (un-)folding procedures for character sets are
|
|
provided.
|
|
|
|
@deffn primitive char-set-cursor cs
|
|
Return a cursor into the character set @var{cs}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-ref cs cursor
|
|
Return the character at the current cursor position
|
|
@var{cursor} in the character set @var{cs}. It is an error to
|
|
pass a cursor for which @code{end-of-char-set?} returns true.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-cursor-next cs cursor
|
|
Advance the character set cursor @var{cursor} to the next
|
|
character in the character set @var{cs}. It is an error if the
|
|
cursor given satisfies @code{end-of-char-set?}.
|
|
@end deffn
|
|
|
|
@deffn primitive end-of-char-set? cursor
|
|
Return @code{#t} if @var{cursor} has reached the end of a
|
|
character set, @code{#f} otherwise.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-fold kons knil cs
|
|
Fold the procedure @var{kons} over the character set @var{cs},
|
|
initializing it with @var{knil}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-unfold p f g seed [base_cs]
|
|
@deffnx primitive char-set-unfold! p f g seed base_cs
|
|
This is a fundamental constructor for character sets.
|
|
@itemize
|
|
@item @var{g} is used to generate a series of ``seed'' values
|
|
from the initial seed: @var{seed}, (@var{g} @var{seed}),
|
|
(@var{g}^2 @var{seed}), (@var{g}^3 @var{seed}), @dots{}
|
|
@item @var{p} tells us when to stop -- when it returns true
|
|
when applied to one of the seed values.
|
|
@item @var{f} maps each seed value to a character. These
|
|
characters are added to the base character set @var{base_cs} to
|
|
form the result; @var{base_cs} defaults to the empty set.
|
|
@end itemize
|
|
|
|
@code{char-set-unfold!} is the side-effecting variant.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-for-each proc cs
|
|
Apply @var{proc} to every character in the character set
|
|
@var{cs}. The return value is not specified.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-map proc cs
|
|
Map the procedure @var{proc} over every character in @var{cs}.
|
|
@var{proc} must be a character -> character procedure.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Creating Character Sets
|
|
@subsection Creating Character Sets
|
|
|
|
New character sets are produced with these procedures.
|
|
|
|
@deffn primitive char-set-copy cs
|
|
Return a newly allocated character set containing all
|
|
characters in @var{cs}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set char1 @dots{}
|
|
Return a character set containing all given characters.
|
|
@end deffn
|
|
|
|
@deffn primitive list->char-set char_list [base_cs]
|
|
@deffnx primitive list->char-set! char_list base_cs
|
|
Convert the character list @var{list} to a character set. If
|
|
the character set @var{base_cs} is given, the character in this
|
|
set are also included in the result.
|
|
|
|
@code{list->char-set!} is the side-effecting variant.
|
|
@end deffn
|
|
|
|
@deffn primitive string->char-set s [base_cs]
|
|
@deffnx primitive string->char-set! s base_cs
|
|
Convert the string @var{str} to a character set. If the
|
|
character set @var{base_cs} is given, the characters in this
|
|
set are also included in the result.
|
|
|
|
@code{string->char-set!} is the side-effecting variant.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-filter pred cs [base_cs]
|
|
@deffnx primitive char-set-filter! pred cs base_cs
|
|
Return a character set containing every character from @var{cs}
|
|
so that it satisfies @var{pred}. If provided, the characters
|
|
from @var{base_cs} are added to the result.
|
|
|
|
@code{char-set-filter!} is the side-effecting variant.
|
|
@end deffn
|
|
|
|
@deffn primitive ucs-range->char-set lower upper [error? base_cs]
|
|
@deffnx primitive uce-range->char-set! lower upper error? base_cs
|
|
Return a character set containing all characters whose
|
|
character codes lie in the half-open range
|
|
[@var{lower},@var{upper}).
|
|
|
|
If @var{error} is a true value, an error is signalled if the
|
|
specified range contains characters which are not contained in
|
|
the implemented character range. If @var{error} is @code{#f},
|
|
these characters are silently left out of the resultung
|
|
character set.
|
|
|
|
The characters in @var{base_cs} are added to the result, if
|
|
given.
|
|
|
|
@code{ucs-range->char-set!} is the side-effecting variant.
|
|
@end deffn
|
|
|
|
@deffn procedure ->char-set x
|
|
Coerce @var{x} into a character set. @var{x} may be a string, a
|
|
character or a character set.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Querying Character Sets
|
|
@subsection Querying Character Sets
|
|
|
|
Access the elements and other information of a character set with these
|
|
procedures.
|
|
|
|
@deffn primitive char-set-size cs
|
|
Return the number of elements in character set @var{cs}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-count pred cs
|
|
Return the number of the elements int the character set
|
|
@var{cs} which satisfy the predicate @var{pred}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set->list cs
|
|
Return a list containing the elements of the character set
|
|
@var{cs}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set->string cs
|
|
Return a string containing the elements of the character set
|
|
@var{cs}. The order in which the characters are placed in the
|
|
string is not defined.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-contains? cs char
|
|
Return @code{#t} iff the character @var{ch} is contained in the
|
|
character set @var{cs}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-every pred cs
|
|
Return a true value if every character in the character set
|
|
@var{cs} satisfies the predicate @var{pred}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-any pred cs
|
|
Return a true value if any character in the character set
|
|
@var{cs} satisfies the predicate @var{pred}.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Character-Set Algebra
|
|
@subsection Character-Set Algebra
|
|
|
|
Character sets can be manipulated with the common set algebra operation,
|
|
such as union, complement, intersection etc. All of these procedures
|
|
provide side--effecting variants, which modify their character set
|
|
argument(s).
|
|
|
|
@deffn primitive char-set-adjoin cs char1 @dots{}
|
|
@deffnx primitive char-set-adjoin! cs char1 @dots{}
|
|
Add all character arguments to the first argument, which must
|
|
be a character set.
|
|
@end deffn
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|
|
|
@deffn primitive char-set-delete cs char1 @dots{}
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|
@deffnx primitive char-set-delete! cs char1 @dots{}
|
|
Delete all character arguments from the first argument, which
|
|
must be a character set.
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|
@end deffn
|
|
|
|
@deffn primitive char-set-complement cs
|
|
@deffnx primitive char-set-complement! cs
|
|
Return the complement of the character set @var{cs}.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-union cs1 @dots{}
|
|
@deffnx primitive char-set-union! cs1 @dots{}
|
|
Return the union of all argument character sets.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-intersection cs1 @dots{}
|
|
@deffnx primitive char-set-intersection! cs1 @dots{}
|
|
Return the intersection of all argument character sets.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-difference cs1 @dots{}
|
|
@deffnx primitive char-set-difference! cs1 @dots{}
|
|
Return the difference of all argument character sets.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-xor cs1 @dots{}
|
|
@deffnx primitive char-set-xor! cs1 @dots{}
|
|
Return the exclusive--or of all argument character sets.
|
|
@end deffn
|
|
|
|
@deffn primitive char-set-diff+intersection cs1 @dots{}
|
|
@deffnx primitive char-set-diff+intersection! cs1 @dots{}
|
|
Return the difference and the intersection of all argument
|
|
character sets.
|
|
@end deffn
|
|
|
|
|
|
@c ===================================================================
|
|
|
|
@node Standard Character Sets
|
|
@subsection Standard Character Sets
|
|
|
|
In order to make the use of the character set data type and procedures
|
|
useful, several predefined character set variables exist.
|
|
|
|
@defvar char-set:lower-case
|
|
All lower--case characters.
|
|
@end defvar
|
|
|
|
@defvar char-set:upper-case
|
|
All upper--case characters.
|
|
@end defvar
|
|
|
|
@defvar char-set:title-case
|
|
This is empty, because ASCII has no titlecase characters.
|
|
@end defvar
|
|
|
|
@defvar char-set:letter
|
|
All letters, e.g. the union of @code{char-set:lower-case} and
|
|
@code{char-set:upper-case}.
|
|
@end defvar
|
|
|
|
@defvar char-set:digit
|
|
All digits.
|
|
@end defvar
|
|
|
|
@defvar char-set:letter+digit
|
|
The union of @code{char-set:letter} and @code{char-set:digit}.
|
|
@end defvar
|
|
|
|
@defvar char-set:graphic
|
|
All characters which would put ink on the paper.
|
|
@end defvar
|
|
|
|
@defvar char-set:printing
|
|
The union of @code{char-set:graphic} and @code{char-set:whitespace}.
|
|
@end defvar
|
|
|
|
@defvar char-set:whitespace
|
|
All whitespace characters.
|
|
@end defvar
|
|
|
|
@defvar char-set:blank
|
|
All horizontal whitespace characters, that is @code{#\space} and
|
|
@code{#\tab}.
|
|
@end defvar
|
|
|
|
@defvar char-set:iso-control
|
|
The ISO control characters with the codes 0--31 and 127.
|
|
@end defvar
|
|
|
|
@defvar char-set:punctuation
|
|
The characters @code{!"#%&'()*,-./:;?@@[\\]_@{@}}
|
|
@end defvar
|
|
|
|
@defvar char-set:symbol
|
|
The characters @code{$+<=>^`|~}.
|
|
@end defvar
|
|
|
|
@defvar char-set:hex-digit
|
|
The hexadecimal digits @code{0123456789abcdefABCDEF}.
|
|
@end defvar
|
|
|
|
@defvar char-set:ascii
|
|
All ASCII characters.
|
|
@end defvar
|
|
|
|
@defvar char-set:empty
|
|
The empty character set.
|
|
@end defvar
|
|
|
|
@defvar char-set:full
|
|
This character set contains all possible characters.
|
|
@end defvar
|