@menu
* Scheme Syntax:: Standard and extended Scheme syntax.
* Scheme Read:: Reading Scheme code.
+* Scheme Write:: Writing Scheme values to a port.
* Fly Evaluation:: Procedures for on the fly evaluation.
* Compilation:: How to compile Scheme files and procedures.
* Loading:: Loading Scheme code from file.
* Character Encoding of Source Files:: Loading non-ASCII Scheme code from file.
* Delayed Evaluation:: Postponing evaluation until it is needed.
-* Evaluator Behaviour:: Modifying Guile's evaluator.
* VM Behaviour:: Modifying Guile's virtual machine.
@end menu
are the same in R5RS Scheme, but are different in Guile.
It is possible to turn off case sensitivity in Guile by setting the
-reader option @code{case-insensitive}. More on reader options can be
-found at (@pxref{Reader options}).
+reader option @code{case-insensitive}. For more information on reader
+options, @xref{Scheme Read}.
@lisp
(read-enable 'case-insensitive)
@end deffn
The behaviour of Guile's Scheme reader can be modified by manipulating
-its read options. For more information about options, @xref{User level
-options interfaces}. If you want to know which reader options are
-available, @xref{Reader options}.
-
-@c FIXME::martin: This is taken from libguile/options.c. Is there
-@c actually a difference between 'help and 'full?
+its read options.
+@cindex options - read
+@cindex read options
@deffn {Scheme Procedure} read-options [setting]
Display the current settings of the read options. If @var{setting} is
omitted, only a short form of the current read options is printed.
-Otherwise, @var{setting} should be one of the following symbols:
-@table @code
-@item help
-Display the complete option settings.
-@item full
-Like @code{help}, but also print programmer options.
-@end table
+Otherwise if @var{setting} is the symbol @code{help}, a complete options
+description is displayed.
@end deffn
+The set of available options, and their default values, may be had by
+invoking @code{read-options} at the prompt.
+
+@smalllisp
+scheme@@(guile-user)> (read-options)
+(square-brackets keywords #f positions)
+scheme@@(guile-user)> (read-options 'help)
+copy no Copy source code expressions.
+positions yes Record positions of source code expressions.
+case-insensitive no Convert symbols to lower case.
+keywords #f Style of keyword recognition: #f, 'prefix or 'postfix.
+r6rs-hex-escapes no Use R6RS variable-length character and string hex escapes.
+square-brackets yes Treat `[' and `]' as parentheses, for R6RS compatibility.
+@end smalllisp
+
+The boolean options may be toggled with @code{read-enable} and
+@code{read-disable}. The non-boolean @code{keywords} option must be set
+using @code{read-set!}.
+
@deffn {Scheme Procedure} read-enable option-name
@deffnx {Scheme Procedure} read-disable option-name
@deffnx {Scheme Procedure} read-set! option-name value
@code{read-set!} can be used to set an option to a specific value.
@end deffn
-@deffn {Scheme Procedure} read-options-interface [setting]
-@deffnx {C Function} scm_read_options (setting)
-Option interface for the read options. Instead of using
-this procedure directly, use the procedures @code{read-enable},
-@code{read-disable}, @code{read-set!} and @code{read-options}.
+For example, to make @code{read} fold all symbols to their lower case
+(perhaps for compatibility with older Scheme code), you can enter:
+
+@lisp
+(read-enable 'case-insensitive)
+@end lisp
+
+For more information on the effect of the @code{r6rs-hex-escapes} option, see
+(@pxref{String Syntax}).
+
+
+@node Scheme Write
+@subsection Writing Scheme Values
+
+Any scheme value may be written to a port. Not all values may be read
+back in (@pxref{Scheme Read}), however.
+
+@rnindex write
+@rnindex print
+@deffn {Scheme Procedure} write obj [port]
+Send a representation of @var{obj} to @var{port} or to the current
+output port if not given.
+
+The output is designed to be machine readable, and can be read back
+with @code{read} (@pxref{Scheme Read}). Strings are printed in
+double quotes, with escapes if necessary, and characters are printed in
+@samp{#\} notation.
+@end deffn
+
+@rnindex display
+@deffn {Scheme Procedure} display obj [port]
+Send a representation of @var{obj} to @var{port} or to the current
+output port if not given.
+
+The output is designed for human readability, it differs from
+@code{write} in that strings are printed without double quotes and
+escapes, and characters are printed as per @code{write-char}, not in
+@samp{#\} form.
+@end deffn
+
+As was the case with the Scheme reader, there are a few options that
+affect the behavior of the Scheme printer.
+
+@cindex options - print
+@cindex print options
+@deffn {Scheme Procedure} print-options [setting]
+Display the current settings of the read options. If @var{setting} is
+omitted, only a short form of the current read options is
+printed. Otherwise if @var{setting} is the symbol @code{help}, a
+complete options description is displayed.
+@end deffn
+
+The set of available options, and their default values, may be had by
+invoking @code{print-options} at the prompt.
+
+@smalllisp
+scheme@@(guile-user)> (print-options)
+(quote-keywordish-symbols reader highlight-suffix "@}" highlight-prefix "@{")
+scheme@@(guile-user)> (print-options 'help)
+highlight-prefix @{ The string to print before highlighted values.
+highlight-suffix @} The string to print after highlighted values.
+quote-keywordish-symbols reader How to print symbols that have a colon
+ as their first or last character. The
+ value '#f' does not quote the colons;
+ '#t' quotes them; 'reader' quotes them
+ when the reader option 'keywords' is
+ not '#f'.
+@end smalllisp
+
+These options may be modified with the print-set! procedure.
+
+@deffn {Scheme Procedure} print-set! option-name value
+Modify the print options.
@end deffn
@end deffn
-@node Evaluator Behaviour
-@subsection Evaluator Behaviour
-
-@c FIXME::martin: Maybe this node name is bad, but the old name clashed with
-@c `Evaluator options' under `Options and Config'.
-
-The behaviour of Guile's evaluator can be modified by manipulating the
-evaluator options. For more information about options, @xref{User level
-options interfaces}.
-
-@c FIXME::martin: Why aren't these procedure named like the other options
-@c procedures?
-
-@deffn {Scheme Procedure} traps [setting]
-Display the current settings of the evaluator traps options. If
-@var{setting} is omitted, only a short form of the current evaluator
-traps options is printed. Otherwise, @var{setting} should be one of the
-following symbols:
-@table @code
-@item help
-Display the complete option settings.
-@item full
-Like @code{help}, but also print programmer options.
-@end table
-@end deffn
-
-@deffn {Scheme Procedure} trap-enable option-name
-@deffnx {Scheme Procedure} trap-disable option-name
-@deffnx {Scheme Procedure} trap-set! option-name value
-Modify the evaluator options. @code{trap-enable} should be used with boolean
-options and switches them on, @code{trap-disable} switches them off.
-@code{trap-set!} can be used to set an option to a specific value.
-
-See @ref{Evaluator trap options} for more information on the available
-trap handlers.
-@end deffn
-
-@deffn {Scheme Procedure} evaluator-traps-interface [setting]
-@deffnx {C Function} scm_evaluator_traps (setting)
-Option interface for the evaluator trap options.
-@end deffn
-
@node VM Behaviour
@subsection VM Behaviour
HCoop / bpt / guile.git / blobdiff