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The following functions are provided by
(use-modules (ice-9 readline))
There are two ways to use readline from Scheme code, either make calls
to readline
directly to get line by line input, or use the
readline port below with all the usual reading functions.
Read a line of input from the user and return it as a string (without
a newline at the end). prompt is the prompt to show, or the
default is the string set in set-readline-prompt!
below.
(readline "Type something: ") ⇒ "hello"
Set the input and output port the readline function should read from and write to. port must be a file port (see File Ports), and should usually be a terminal.
The default is the current-input-port
and
current-output-port
(see Default Ports) when (ice-9
readline)
loads, which in an interactive user session means the Unix
“standard input” and “standard output”.
Return a buffered input port (see Buffered Input) which calls the
readline
function above to get input. This port can be used
with all the usual reading functions (read
, read-char
,
etc), and the user gets the interactive editing features of readline.
There’s only a single readline port created. readline-port
creates it when first called, and on subsequent calls just returns
what it previously made.
If the current-input-port
is a terminal (see isatty?
) then enable readline for all reading from
current-input-port
(see Default Ports) and enable readline
features in the interactive REPL (see The REPL).
(activate-readline) (read-char)
activate-readline
enables readline on current-input-port
simply by a set-current-input-port
to the readline-port
above. An application can do that directly if the extra REPL features
that activate-readline
adds are not wanted.
Set the prompt string to print when reading input. This is used when
reading through readline-port
, and is also the default prompt
for the readline
function above.
prompt1 is the initial prompt shown. If a user might enter an expression across multiple lines, then prompt2 is a different prompt to show further input required. In the Guile REPL for instance this is an ellipsis (‘...’).
See set-buffered-input-continuation?!
(see Buffered Input)
for an application to indicate the boundaries of logical expressions
(assuming of course an application has such a notion).
Call (thunk)
with completer as the readline tab
completion function to be used in any readline calls within that
thunk. completer can be #f
for no completion.
completer will be called as (completer text state)
,
as described in (see How Completing Works in GNU Readline
Library). text is a partial word to be completed, and each
completer call should return a possible completion string or
#f
when no more. state is #f
for the first call
asking about a new text then #t
while getting further
completions of that text.
Here’s an example completer for user login names from the
password file (see User Information), much like readline’s own
rl_username_completion_function
,
(define (username-completer-function text state) (if (not state) (setpwent)) ;; new, go to start of database (let more ((pw (getpwent))) (if pw (if (string-prefix? text (passwd:name pw)) (passwd:name pw) ;; this name matches, return it (more (getpwent))) ;; doesn't match, look at next (begin ;; end of database, close it and return #f (endpwent) #f))))
A completion function offering completions for Guile functions and
variables (all define
s). This is the default completion
function.
A completion function offering filename completions. This is
readline’s rl_filename_completion_function
(see Completion
Functions in GNU Readline Library).
Return a completion function which offers completions from the possibilities in string-list. Matching is case-sensitive.
Previous: Readline Options, Up: Readline Support [Contents][Index]