-;;; Print an error message for a non-EOF error on STREAM. OLD-POS is a
-;;; preceding file position that hopefully comes before the beginning
-;;; of the line. Of course, this only works on streams that support
-;;; the file-position operation.
-(defun normal-read-error (stream old-pos condition)
- (declare (type stream stream) (type unsigned-byte old-pos))
- (let ((pos (file-position stream)))
- (file-position stream old-pos)
- (let ((start old-pos))
- (loop
- (let ((line (read-line stream nil))
- (end (file-position stream)))
- (when (>= end pos)
- ;; FIXME: READER-ERROR also prints the file position. Do we really
- ;; need to try to give position information here?
- (compiler-abort "read error at ~D:~% \"~A/\\~A\"~%~A"
- pos
- (string-left-trim " "
- (subseq line 0 (- pos start)))
- (subseq line (- pos start))
- condition)
- (return))
- (setq start end)))))
- (values))
-
-;;; Back STREAM up to the position Pos, then read a form with
-;;; *READ-SUPPRESS* on, discarding the result. If an error happens
-;;; during this read, then bail out using COMPILER-ERROR (fatal in
-;;; this context).
-(defun ignore-error-form (stream pos)
- (declare (type stream stream) (type unsigned-byte pos))
- (file-position stream pos)
- (handler-case (let ((*read-suppress* t))
- (read stream))
- (error (condition)
- (declare (ignore condition))
- (compiler-error "unable to recover from read error"))))
-
-;;; Print an error message giving some context for an EOF error. We
-;;; print the first line after POS that contains #\" or #\(, or
-;;; lacking that, the first non-empty line.
-(defun unexpected-eof-error (stream pos condition)
- (declare (type stream stream) (type unsigned-byte pos))
- (let ((res nil))
- (file-position stream pos)
- (loop
- (let ((line (read-line stream nil nil)))
- (unless line (return))
- (when (or (find #\" line) (find #\( line))
- (setq res line)
- (return))
- (unless (or res (zerop (length line)))
- (setq res line))))
- (compiler-abort "read error in form starting at ~D:~%~@[ \"~A\"~%~]~A"
- pos
- res
- condition))
- (file-position stream (file-length stream))
- (values))
-
-;;; Read a form from STREAM, returning EOF at EOF. If a read error
-;;; happens, then attempt to recover if possible, returning a proxy
-;;; error form.
-;;;
-;;; FIXME: This seems like quite a lot of complexity, and it seems
-;;; impossible to get it quite right. (E.g. the `(CERROR ..) form
-;;; returned here won't do the right thing if it's not in a position
-;;; for an executable form.) I think it might be better to just stop
-;;; trying to recover from read errors, punting all this noise
-;;; (including UNEXPECTED-EOF-ERROR and IGNORE-ERROR-FORM) and doing a
-;;; COMPILER-ABORT instead.
-(defun careful-read (stream eof pos)
- (handler-case (read stream nil eof)
- (error (condition)
- (let ((new-pos (file-position stream)))
- (cond ((= new-pos (file-length stream))
- (unexpected-eof-error stream pos condition))
- (t
- (normal-read-error stream pos condition)
- (ignore-error-form stream pos))))
- '(cerror "Skip this form."
- "compile-time read error"))))
+;;; Read a form from STREAM; or for EOF, use the trick popularized by
+;;; Kent Pitman of returning STREAM itself. If an error happens, then
+;;; convert it to standard abort-the-compilation error condition
+;;; (possibly recording some extra location information).
+(defun read-for-compile-file (stream position)
+ (handler-case (read stream nil stream)
+ (reader-error (condition)
+ (error 'input-error-in-compile-file
+ :error condition
+ ;; We don't need to supply :POSITION here because
+ ;; READER-ERRORs already know their position in the file.
+ ))
+ ;; ANSI, in its wisdom, says that READ should return END-OF-FILE
+ ;; (and that this is not a READER-ERROR) when it encounters end of
+ ;; file in the middle of something it's trying to read.
+ (end-of-file (condition)
+ (error 'input-error-in-compile-file
+ :error condition
+ ;; We need to supply :POSITION here because the END-OF-FILE
+ ;; condition doesn't carry the position that the user
+ ;; probably cares about, where the failed READ began.
+ :position position))))