mirror of
https://github.com/ashinn/chibi-scheme.git
synced 2025-05-19 21:59:17 +02:00
dddc6d1806
Documentation looks much nicer now (or at least more familiar). Test cases become ugly because we need to double the escape in strings. Also escaping requires \"\\" which in a Scheme string gets written \\"\\\\". Consider \\ as a shortcut (which is still \\\\ in a string).
422 lines
15 KiB
Scheme
422 lines
15 KiB
Scheme
;; repl.scm - friendlier repl with line editing and signal handling
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;; Copyright (c) 2012-2013 Alex Shinn. All rights reserved.
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;; BSD-style license: http://synthcode.com/license.txt
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;;> A user-friendly REPL with line editing and signal handling.
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;;> The default REPL provided by chibi-scheme is very minimal,
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;;> meant primarily to be small and work on any platform. This
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;;> module provides an advanced REPL that handles vt100 line
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;;> editing and signal handling, so that C-c will interrupt a
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;;> computation and bring you back to the REPL prompt. To use
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;;> this repl, run
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;;> \command{chibi-scheme -mchibi.repl -e'(repl)'}
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;;> from the command line or within Emacs.
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(define (with-signal-handler sig handler thunk)
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(let ((old-handler #f))
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(dynamic-wind
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(lambda () (set! old-handler (set-signal-action! sig handler)))
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thunk
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(lambda () (set-signal-action! sig old-handler)))))
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(define (warn msg . args)
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(let ((out (current-error-port)))
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(display msg out)
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(for-each (lambda (x) (write-char #\space out) (write x out)) args)
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(newline out)))
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(define (write-to-string x)
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(call-with-output-string (lambda (out) (write x out))))
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(define (complete-sexp? str)
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(call-with-input-string str
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(lambda (in)
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(let lp () (if (not (eof-object? (read/ss in))) (lp))))))
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(define (read-line/complete-sexp in)
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(let lp ((res ""))
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(let ((line (read-line in)))
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(cond
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((eof-object? line)
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(if (equal? res "") line res))
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(else
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(let ((res (string-append res line "\n")))
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(if (protect (exn (else #f)) (complete-sexp? res))
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res
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(lp res))))))))
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(define (buffer-complete-sexp? buf)
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(complete-sexp? (buffer->string buf)))
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(define module? vector?)
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(define (module-env mod) (vector-ref mod 1))
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(define (all-exports env)
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(let lp ((env env) (res '()))
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(if (not env)
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res
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(lp (env-parent env) (append (env-exports env) res)))))
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(define (string-common-prefix-length strings)
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(if (null? strings)
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0
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(let lp ((len (string-length (car strings)))
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(prev (car strings))
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(ls (cdr strings)))
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(if (or (null? ls) (zero? len))
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len
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(lp (min len (string-mismatch prev (car ls)))
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(car ls)
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(cdr ls))))))
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(define (make-sexp-buffer-completer)
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(buffer-make-completer
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(lambda (buf word)
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(let* ((len (string-length word))
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(candidates
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(filter
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(lambda (w)
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(and (>= (string-length w) len)
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(equal? word (substring w 0 len))))
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(map symbol->string (all-exports (interaction-environment)))))
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(prefix-len (string-common-prefix-length candidates)))
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(if (> prefix-len len)
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(list (substring (car candidates) 0 prefix-len))
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(sort candidates))))))
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(define (describe x . o)
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(let ((out (if (pair? o) (car o) (current-output-port))))
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(cond
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((null? x)
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(display "empty list\n" out))
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((list? x)
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(display "list of length " out) (write (length x) out) (newline out)
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(let lp ((ls x) (i 0))
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(cond
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((pair? ls)
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(display " " out) (write i out) (display ": " out)
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(write/ss (car ls) out) (newline out)
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(lp (cdr ls) (+ i 1))))))
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((pair? x)
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(display "pair with car " out) (write/ss (car x) out) (newline out)
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(display "and cdr " out) (write/ss (cdr x) out) (newline out))
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((vector? x)
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(let ((len (vector-length x)))
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(display "vector of length " out) (write len out) (newline out)
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(let lp ((i 0))
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(cond
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((< i len)
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(display " " out) (write i out) (display ": " out)
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(write/ss (vector-ref x i) out) (newline out)
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(lp (+ i 1)))))))
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((boolean? x)
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(display (if x "boolean true\n" "boolean false\n") out))
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((char? x)
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(let ((n (char->integer x)))
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(display "character " out) (write x out)
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(display ", code: " out) (write n out)
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(display ", #x" out) (display (number->string n 16) out)
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(display ", #o" out) (display (number->string n 8) out)
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(newline out)))
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((and (integer? x) (exact? x))
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(display "exact integer " out) (write x out)
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(display "\n #x" out) (display (number->string x 16) out)
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(display "\n #o" out) (display (number->string x 8) out)
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(display "\n #b" out) (display (number->string x 2) out)
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(newline out))
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(else
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(write/ss x out) (newline out)))))
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;;> Runs an interactive REPL. Repeatedly displays a prompt,
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;;> then Reads an expression, Evaluates the expression, Prints
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;;> the result then Loops. Terminates when the end of input is
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;;> reached or the \scheme|{\exit}| command is given.
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;;>
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;;> Basic Emacs-style line editing with persistent history
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;;> completion is provided. C-c can be used to interrupt the
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;;> current computation and drop back to the prompt. The
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;;> following keyword arguments customize the REPL:
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;;>
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;;> \itemlist[
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;;> \item{\scheme{in:} - the input port (default \scheme{(current-input-port)})}
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;;> \item{\scheme{out:} - the output port (default \scheme{(current-output-port)})}
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;;> \item{\scheme{module:} - the initial module}
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;;> \item{\scheme{environment:} - the initial environment (default \scheme{(interaction-environment)})}
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;;> \item{\scheme{escape:} - the command escape character (default \scheme|{#\\}|)}
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;;> \item{\scheme{make-prompt:} - a procedure taking one argument (the current module name as a list) and returning a string to be used as the prompt}
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;;> \item{\scheme{history:} - the initial command history}
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;;> \item{\scheme{history-file:} - the file to save history to (default ~/.chibi-repl-history)}
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;;> ]
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;;>
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;;> The module: and environment: keyword arguments should not both be given.
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;;>
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;;> REPL commands in the style of \hyperlink["http://s48.org/"]{Scheme48}
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;;> are available to control out-of-band properties. By default a
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;;> command is written as an identifier beginning with an "@"
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;;> character, but this can be customized with the \scheme{escape:}
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;;> keyword. The following commands are available:
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;;>
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;;> \itemlist[
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;;> \item{\scheme|{\import <import-spec>}| - import the \var{<import-spec>} in the \scheme{interaction-environment}, useful if the \scheme{import} binding is not available}
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;;> \item{\scheme|{\import-only <import-spec>}| - replace the \scheme{interaction-environment} with the given \var{<import-spec>}}
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;;> \item{\scheme|{\in [<module>]}| - switch to \var{<module>}, or the \scheme{interaction-environment} if \var{<module>} is not specified}
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;;> \item{\scheme|{\meta <expr>}| - evaluate \var{<expr>} in the \scheme{(meta)} module}
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;;> \item{\scheme|{\meta-module-is <module>}| - switch the meta module to \var{<module>}}
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;;> \item{\scheme|{\exit}| - exit the REPL}
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;;> ]
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(define-record-type Repl
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(make-repl
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in out escape module env meta-env make-prompt history-file history raw?)
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repl?
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(in repl-in repl-in-set!)
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(out repl-out repl-out-set!)
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(escape repl-escape repl-escape-set!)
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(module repl-module repl-module-set!)
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(env repl-env repl-env-set!)
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(meta-env repl-meta-env repl-meta-env-set!)
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(make-prompt repl-make-prompt repl-make-prompt-set!)
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(history-file repl-history-file repl-history-file-set!)
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(history repl-history repl-history-set!)
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(raw? repl-raw? repl-raw?-set!))
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(define (repl/import-aux rp args meta continue only?)
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(let* ((mod-name (cadr args))
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(mod+imps (eval `(resolve-import ',mod-name) (repl-meta-env rp))))
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(cond
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((pair? mod+imps)
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(protect
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(exn
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(else
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(print-exception exn (current-error-port))
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(warn "error loading module:" mod-name)
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(continue rp)))
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(let ((env (if only? (make-environment) (repl-env rp)))
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(imp-env
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(module-env
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(eval `(load-module ',(car mod+imps)) (repl-meta-env rp)))))
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(%import env imp-env (cdr mod+imps) #f)
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(repl-env-set! rp env)
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(continue rp))))
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(else
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(warn "couldn't find module:" mod-name)
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(continue rp)))))
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(define (repl/import rp args meta continue)
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(repl/import-aux rp args meta continue #f))
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(define (repl/import-only rp args meta continue)
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(repl/import-aux rp args meta continue #t))
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(define (repl/in rp args meta continue)
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(cond
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((null? (cdr args))
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(repl-module-set! rp #f)
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(repl-env-set! rp (interaction-environment)))
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((eval `(load-module ',(cadr args)) (repl-meta-env rp))
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=> (lambda (m)
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(repl-module-set! rp (cadr args))
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(repl-env-set! rp (module-env m))))
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(else
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(warn "couldn't find module:" (cadr args))))
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(continue rp))
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(define (repl/meta rp args meta continue)
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(cond
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((null? (cdr args))
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(warn "usage: @meta <expr>")
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(continue rp))
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((and (symbol? (cadr args))
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(eqv? (repl-escape rp) (string-ref (symbol->string (cadr args)) 0)))
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(meta rp (cdr args) (lambda _ (continue rp))))
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(else
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(eval (cadr args) (repl-meta-env rp))
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(continue rp))))
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(define (repl/meta-module-is rp args meta continue)
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(cond
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((null? (cdr args))
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(warn "usage: @meta-module-is <module>"))
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((eval `(load-module ',(cadr args)) (repl-meta-env rp))
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=> (lambda (m) (repl-meta-env-set! rp (module-env m))))
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(else
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(warn "couldn't find module:" (cadr args))))
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(continue rp))
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(define (repl/help rp args meta continue)
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(let ((out (repl-out rp)))
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(cond
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((null? (cdr args))
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(display "Try @help <identifier> [<module>]\n" out))
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((null? (cddr args))
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(let* ((failed (list 'failed))
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(val (protect (exn (else (print-exception exn) failed))
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(eval (second args) (repl-env rp))))
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(mod (and (procedure? val) (containing-module val))))
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(cond
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(mod
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(write val out) (newline out) (newline out)
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(print-module-binding-docs (car mod) (second args) out))
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((not (eq? val failed))
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(describe val out)))))
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(else
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(protect (exn (else (print-exception exn (current-error-port))))
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(print-module-binding-docs (third args) (second args) out))))
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(continue rp)))
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(define (repl/exit rp args meta continue)
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;; To exit the repl simply don't call continue.
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#f)
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;; Utility to read all objects from a port accumulated into a list.
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(define (read/ss/all port)
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(let loop ((l '()))
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(let ((x (read/ss port)))
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(if (eof-object? x)
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(reverse l)
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(loop (cons x l))))))
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(define (string->sexp-list str)
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(call-with-input-string str read/ss/all))
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(define (repl/eval rp expr-list)
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(let ((out (repl-out rp)))
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(protect (exn (else (print-exception exn out)))
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(let ((thread
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(make-thread
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(lambda ()
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;; The inner protect in the child thread catches errors
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;; from eval.
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(protect (exn (else (print-exception exn out)))
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(for-each
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(lambda (expr)
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(call-with-values (lambda () (eval expr (repl-env rp)))
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(lambda res-list
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(cond
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((not (or (null? res-list)
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(equal? res-list (list (if #f #f)))))
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(write/ss (car res-list) out)
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(for-each
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(lambda (res)
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(write-char #\space out)
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(write/ss res out))
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(cdr res-list))
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(newline out))))))
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expr-list))))))
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;; If an interrupt occurs while the child thread is
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;; still running, terminate it, otherwise wait for it
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;; to complete.
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(with-signal-handler
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signal/interrupt
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(lambda (n)
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(display "\nInterrupt\n" out)
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(thread-terminate! thread))
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(lambda () (thread-join! (thread-start! thread))))))))
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(define (repl/eval-string rp str)
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(repl/eval
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rp
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(protect (exn (else (print-exception exn (current-error-port))))
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;; Ugly wrapper to account for the implicit state mutation
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;; implied by the #!fold-case read syntax.
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(let ((in (repl-in rp))
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(in2 (open-input-string str)))
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(set-port-fold-case! in2 (port-fold-case? in))
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(set-port-line! in2 (port-line in))
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(let ((expr-list (read/ss/all in2)))
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(set-port-fold-case! in (port-fold-case? in2))
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expr-list)))))
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(define (keywords->repl ls)
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(let-keywords* ls
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((in in: (current-input-port))
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(out out: (current-output-port))
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(escape escape: #\@)
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(module module: #f)
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(env
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environment:
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(if module
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(module-env
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(if (module? module) module (load-module module)))
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(interaction-environment)))
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(make-prompt
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make-prompt:
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(lambda (module)
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(string-append (if module (write-to-string module) "") "> ")))
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(history-file
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history-file:
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(string-append (get-environment-variable "HOME")
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"/.chibi-repl-history"))
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(history
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history:
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(or (protect (exn (else #f))
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(list->history (call-with-input-file history-file read)))
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(make-history)))
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(raw? raw?:
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(member (get-environment-variable "TERM") '("emacs" "dumb")))
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(meta-env meta-env: (module-env (load-module '(meta)))))
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(make-repl
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in out escape module env meta-env make-prompt history-file history raw?)))
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(define (repl/edit-line rp)
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(let ((prompt ((repl-make-prompt rp) (repl-module rp)))
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(in (repl-in rp))
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(out (repl-out rp)))
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(cond
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((repl-raw? rp)
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(display prompt out)
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(flush-output out)
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(read-line/complete-sexp in))
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(else
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(edit-line in out
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'prompt: prompt
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'history: (repl-history rp)
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'complete?: buffer-complete-sexp?
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'completion: (make-sexp-buffer-completer))))))
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(define repl-commands
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`((import . ,repl/import)
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(import-only . ,repl/import-only)
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(in . ,repl/in)
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(meta . ,repl/meta)
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(meta-module-is . ,repl/meta-module-is)
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(? . ,repl/help)
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(h . ,repl/help)
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(help . ,repl/help)
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(exit . ,repl/exit)))
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(define (repl . o)
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(let ((rp (keywords->repl o)))
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(let lp ((rp rp))
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(let ((line (repl/edit-line rp)))
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(cond
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((or (not line) (eof-object? line)))
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((equal? line "")
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(history-reset! (repl-history rp))
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(lp rp))
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(else
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(history-commit! (repl-history rp) line)
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(cond
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((and (> (string-length line) 1)
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(eqv? (repl-escape rp) (string-ref line 0)))
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;; @ escaped command
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(let meta ((rp rp)
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(args (string->sexp-list (substring line 1)))
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(continue lp))
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(cond
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((null? args)
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(warn "empty repl command")
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(continue rp))
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((assq (car args) repl-commands)
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=> (lambda (x) ((cdr x) rp args meta continue)))
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(else
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(warn "unknown repl command" (car args))
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(continue rp)))))
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(else
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;; Normal expression to eval.
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(repl/eval-string rp line)
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(lp rp)))))))
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;; Update the history file on completion.
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(if (repl-history-file rp)
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(call-with-output-file (repl-history-file rp)
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(lambda (out) (write (history->list (repl-history rp)) out))))))
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