+(in-package #:syntax-checker)
+
+; Rules
+; * Elements on new line in each form must be indented the same amount
+; * No space/newline after open parens
+; * No form longer than 50 lines
+; * Top level multiline forms must be separated by exactly one space
+; * No line longer than 120 characters
+; * No use of unexported symbols in other packages
+; * No tabs
+; * Only one space between elements in a form on a single line
+; * in-package must be first line in file unless file is package.lisp
+; * No whitespace at end of line
+; * No lines that are only whitespace
+; * No empty lines at end of file
+; * Never have two empty lines in a row
+; * Only one in-package per file
+; * No hanging close parens
+;
+; Exceptions
+; * comments
+; * multiline strings
+; * exclude in-package check from package.lisp
+
+; Some thoughts
+; - form starting reader macros will have to be hand added to this code
+; - exceptions will eventually arise, and the rule file will have to be changed
+; - the proper formatting of "loop" is weird
+
+(define-condition check-failure nil ((msg :initarg :msg :reader check-failure-msg)
+ (line-no :initarg :line-no :reader check-failure-line-no)
+ (col-no :initarg :col-no :reader check-failure-col-no)))
+
+(defvar *state* nil)
+(defvar *line-no* nil)
+(defvar *col-no* nil)
+(defvar *evaluators* nil)
+(defvar *form-stack* nil)
+(defvar *form-ended-on-same-line* nil)
+
+(eval-when (:compile-toplevel :load-toplevel :execute)
+ (defparameter *possible-states*
+ '(:begin ; start of file
+ :normal ; normal processing
+ :beginning-of-line
+ :beginning-of-line-with-separator ; empty space in there
+ :beginning-of-symbols
+ :beginning-of-symbols-with-separator
+ :comment-with-separator ; weird edge case for pre-function comments
+ :beginning-of-line-with-comment-and-separator ; weird edge case part 2
+ :first-symbol ; first symbol of form/line
+ :all ; matches everything
+ :in-string)))
+
+(defun set-state (state)
+ (when (not (find state *possible-states*))
+ (error "Can't set state to ~A" state))
+ (setf *state* state)
+ nil)
+
+(defmacro defevaluator (state match func)
+ (when (not (find state *possible-states*)) (error "~A is an invalid state" state))
+ (let
+ ((scanner (gensym)))
+ `(let
+ ((,scanner (when (stringp ,match) (cl-ppcre:create-scanner ,match))))
+ (pushnew
+ (list
+ (lambda (state text)
+ (and
+ (or (eql :all ,state) (eql ,state state))
+ (or
+ (and (symbolp text) (eql text ,match))
+ (and
+ ,scanner
+ (stringp text)
+ (multiple-value-bind (start end) (cl-ppcre:scan ,scanner text)
+ (and start end (= 0 start)))))))
+ (lambda (text) (second (multiple-value-list (cl-ppcre:scan ,scanner text))))
+ ,func)
+ *evaluators*))))
+
+(defun evaluate (text)
+ (if (string= "" text)
+ (let*
+ ((evaluator (find-if (lambda (f) (funcall f *state* :eof)) *evaluators* :from-end t :key #'car))
+ (problem (when evaluator (funcall (third evaluator)))))
+ (when problem (error (make-condition 'check-failure :msg problem :line-no *line-no* :col-no *col-no*))))
+ (let
+ ((evaluator (find-if (lambda (f) (funcall f *state* text)) *evaluators* :from-end t :key #'car)))
+ (when (not evaluator)
+ (error
+ (make-condition 'check-failure
+ :msg (format nil "Can't check in state ~S: ~S..."
+ *state* (subseq text 0 (min (length text) 10))) :line-no *line-no* :col-no *col-no*)))
+ (let
+ ((problem (funcall (third evaluator))))
+ (when problem
+ (error (make-condition 'check-failure :msg problem :line-no *line-no* :col-no *col-no*)))
+ (let
+ ((length-of-match (funcall (cadr evaluator) text)))
+ (incf *col-no* length-of-match)
+ (when (< 120 *col-no*)
+ (error (make-condition 'check-failure :msg "Line longer than 120 characters" :line-no *line-no* :col-no 0)))
+ (evaluate (subseq text length-of-match)))))))
+
+(defun slurp-file (filename &key (element-type 'character) (sequence-type 'string))
+ (with-open-file (str filename :element-type element-type)
+ (let ((seq (make-sequence sequence-type (file-length str)))) (read-sequence seq str) seq)))
+
+(defun check-file (file)
+ (if (string= "package" (pathname-name file))
+ (set-state :normal)
+ (set-state :begin))
+ (setf *line-no* 0)
+ (setf *col-no* 0)
+ (setf *form-stack* nil)
+ (setf *form-ended-on-same-line* nil)
+ (handler-case
+ (progn
+ (evaluate (slurp-file file))
+ (list :success file))
+ (check-failure (cf)
+ (list :failure file (check-failure-msg cf) (check-failure-line-no cf) (check-failure-col-no cf)))))
+
+(defun check-directory (dir)
+ (mapcar #'check-file (directory (format nil "~A/**/*.lisp" dir))))
+
+(defun any-failures (checks)
+ (find :failure checks :key #'car))
+
+(defun print-failure (failure)
+ (format nil
+ "Style error in ~A at ~A:~A: ~A~%- ~A~%~VT^"
+ (second failure)
+ (1+ (fourth failure))
+ (1+ (fifth failure))
+ (third failure)
+ (with-open-file (str (second failure)) (loop :repeat (fourth failure) :do (read-line str)) (read-line str))
+ (+ (fifth failure) 2)))
+
+(defun pretty-print-check-directory (dir)
+ (let
+ ((checks (check-directory dir)))
+ (format t "In ~A: Checked ~A files with ~A failures~%~%"
+ dir (length checks) (length (remove :success checks :key #'car)))
+ (format t "~{~A~%~}" (mapcar #'print-failure (remove :success checks :key #'car)))
+ (not (any-failures checks))))
+
+; These are in reverse order
+(defevaluator :beginning-of-symbols " *;[^\\n]*"
+ (lambda () (set-state :normal)))
+
+(defevaluator :beginning-of-symbols-with-separator " *;[^\\n]*"
+ (lambda () (set-state :comment-with-separator)))
+
+(defevaluator :normal " *;[^\\n]*"
+ (lambda () (set-state :normal)))
+
+(defevaluator :normal "\\("
+ (lambda ()
+ (push (list *line-no* *col-no*) *form-stack*)
+ (set-state :first-symbol)))
+
+(defevaluator :first-symbol "\\("
+ (lambda ()
+ (cond
+ ((and (not *form-stack*) (not (zerop *col-no*))) "Top level forms must begin on first column")
+ ((and *form-stack* (/= (1+ (cadr (car *form-stack*))) *col-no*))
+ "All form elements must be indented equally")
+ (t
+ (push (list *line-no* *col-no*) *form-stack*)
+ (set-state :first-symbol)))))
+
+(defevaluator :all "\\t" (constantly "Must not use tabs"))
+
+(defevaluator :begin "\\(in-package[^\\)]*\\)" (lambda () (set-state :normal)))
+
+(defevaluator :beginning-of-line-with-separator :eof
+ (lambda ()
+ (incf *line-no* -1)
+ "Must not end with empty line"))
+
+(defevaluator :beginning-of-line-with-separator "\\n" (constantly "Must not have two empty lines in a row"))
+
+(defevaluator :begin ".*" (constantly "Must begin with in-package form"))
+
+(defevaluator :all "\\( *in-package " (constantly "Only one in-package per file"))
+
+(defevaluator :normal "\\n"
+ (lambda ()
+ (incf *line-no*)
+ (setf *col-no* -1)
+ (set-state :beginning-of-line)))
+
+(defevaluator :comment-with-separator "\\n"
+ (lambda ()
+ (incf *line-no*)
+ (setf *col-no* -1)
+ (set-state :beginning-of-line-with-comment-and-separator)
+ nil))
+
+(defevaluator :normal " +\\n" (constantly "No whitespace at end of line"))
+
+(defevaluator :beginning-of-line " *" (lambda () (set-state :beginning-of-symbols)))
+
+(defevaluator :beginning-of-line-with-separator " *" (lambda () (set-state :beginning-of-symbols-with-separator)))
+
+(defevaluator :beginning-of-line-with-comment-and-separator "\\n"
+ (lambda ()
+ (progn
+ (incf *line-no*)
+ (setf *col-no* -1)
+ (set-state :beginning-of-line-with-separator))))
+
+(defevaluator :beginning-of-line-with-comment-and-separator " *"
+ (lambda () (set-state :beginning-of-symbols-with-separator)))
+
+(defevaluator :beginning-of-symbols "\\n"
+ (lambda ()
+ (if
+ (< 0 *col-no*)
+ "No whitespace only lines"
+ (progn
+ (incf *line-no*)
+ (setf *col-no* -1)
+ (set-state :beginning-of-line-with-separator)))))
+
+(defevaluator :beginning-of-symbols "\\)" (constantly "No hanging close parens"))
+
+(defevaluator :beginning-of-symbols-with-separator "\\)" (constantly "No hanging close parens"))
+
+(defevaluator :beginning-of-symbols ""
+ (lambda ()
+ (if
+ (and (not *form-stack*) (not *form-ended-on-same-line*))
+ "Multiline top level forms must be separated by a space"
+ (set-state :first-symbol))))
+
+(defevaluator :beginning-of-symbols-with-separator ""
+ (lambda ()
+ (set-state :first-symbol)))
+
+(defevaluator :normal "\\)"
+ (lambda ()
+ (let
+ ((form (pop *form-stack*)))
+ (cond
+ ((not form) "Unmatched ending paren")
+ ((< 50 (- *line-no* (car form))) "Forms can't be over 50 lines long")
+ (t (setf *form-ended-on-same-line* (= *line-no* (car form))) nil)))))
+
+(defevaluator :normal "::" (constantly "No internal symbols from other packages"))
+
+(defevaluator :in-string "\\\\\"" (constantly nil))
+
+(defevaluator :normal "\"" (lambda () (set-state :in-string)))
+
+(defevaluator :in-string "\"" (lambda () (set-state :normal)))
+
+(defevaluator :in-string "\\n"
+ (lambda ()
+ (incf *line-no*)
+ (setf *col-no* -1)
+ nil))
+
+(defevaluator :in-string "." (constantly nil))
+
+(defevaluator :first-symbol "\\n" (constantly "No new line after opening form"))
+
+(defevaluator :first-symbol " " (constantly "No space after opening parens"))
+
+(defevaluator :first-symbol ""
+ (lambda ()
+ (cond
+ ((and *form-stack* (/= (1+ (cadr (car *form-stack*))) *col-no*))
+ "All form elements must be indented equally")
+ (t (set-state :normal)))))
+
+(defevaluator :normal " " (constantly "Only one space between items of a form"))
+
+(defevaluator :normal "." (constantly nil))