Create the scanner monad and experiment with it

This commit is contained in:
Greg Sexton 2014-03-19 21:45:52 +00:00
parent 3d727df657
commit 5b97990a0d

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@ -4,7 +4,7 @@
;; Version: 1.0
;; Keywords: folding
;; URL: https://github.com/gregsexton/
;; Package-Requires: ((emacs "24"))
;; Package-Requires: ((s "1.9.0") (dash "2.5.0") (emacs "24"))
;; The MIT License (MIT)
@ -32,7 +32,8 @@
;;; Code:
;;; customisation
(require 'dash)
(require 's)
;;; fold structure
@ -59,15 +60,16 @@ used to nil out data. This mutates the node."
(aset node 4 data)
(aref node 4)))
(defun origami-fold-open-set (node value)
(origami-fold-node (origami-fold-beg node)
(origami-fold-end node)
value
(origami-fold-children node)
(origami-fold-data node)))
;;; need to rewrite the fold tree structure from the node downwards
;; (defun origami-fold-open-set (node value)
;; (origami-fold-node (origami-fold-beg node)
;; (origami-fold-end node)
;; value
;; (origami-fold-children node)
;; (origami-fold-data node)))
(defun origami-fold-open-toggle (node)
(origami-fold-open-set node (not (origami-fold-open-p node))))
;; (defun origami-fold-open-toggle (node)
;; (origami-fold-open-set node (not (origami-fold-open-p node))))
(defun origami-fold-range-equal (a b)
(and (equal (origami-fold-beg a) (origami-fold-beg b))
@ -77,8 +79,6 @@ used to nil out data. This mutates the node."
(equal (origami-fold-open-p a) (origami-fold-open-p b)))
(defun origami-fold-diff (old new on-add on-remove on-change)
"Diff the two structures calling ON-ADD for nodes that have
been added and ON-REMOVE for nodes that have been removed."
(cl-labels ((diff-children (old-children new-children)
(let ((old (car old-children))
(new (car new-children)))
@ -143,6 +143,74 @@ been added and ON-REMOVE for nodes that have been removed."
;; TODO:
)
;;; content structure
(defun origami-content (consumed string)
"Create a content structure from STRING and the count of CONSUMED characters."
(cons consumed string))
(defun origami-content-consumed-count (content) (car content))
(defun origami-content-string (content) (cdr content))
(defun origami-content-from (content consumed)
"Create a new content after consuming CONSUMED chars."
(origami-content (+ (origami-content-consumed-count content) consumed)
(substring (origami-content-string content) consumed)))
;;; scanner
(defun origami-scanner-bind (h f)
"State monad composed with the maybe monad."
(if (null h) nil
(lambda (s)
(let ((new-result (funcall h s)))
(if (null new-result) nil
(destructuring-bind (new-value . new-state) new-result
(funcall (funcall f new-value) new-state)))))))
;;; TODO: reimplement this as a macro so that intermediate results are
;;; visible. Basically implement proper do notation.
(defun origami-scanner-bind-chain (scanner &rest funs)
(-reduce-from (lambda (acc f) (origami-scanner-bind acc f)) scanner funs))
(defun origami-scanner-return (x)
(lambda (s) (cons x s)))
(defun origami-run-scanner (scanner content)
(funcall scanner content))
(defun origami-scan (buffer scanner)
(with-current-buffer buffer
(let ((contents (buffer-string)))
(origami-run-scanner scanner (origami-content 0 contents)))))
(defun origami-scanner-consume (prefix content)
(lambda (state)
(when (s-prefix-p prefix (origami-content-string content))
(cons (origami-content-from content (length prefix)) state))))
(defun origami-pair-scanner (start end skip)
(lambda (content)
(origami-scanner-bind-chain
(origami-scanner-consume start content)
;; skip
(lambda (skip-content) (origami-scanner-consume end skip-content))
(lambda (new-content)
(lambda (state)
(cons new-content (cons (list (origami-content-consumed-count content)
(origami-content-consumed-count new-content))
state)))))))
;;; TODO: maybe scan and build up a simple list of (start end) values,
;;; in the next pass transform this in to the proper fold structure?
(origami-run-scanner
(origami-scanner-bind
(origami-scanner-return (origami-content 0 "{}"))
(origami-pair-scanner "{" "}" nil))
'foo) ;=> ((2 . "") . foo)
;;; commands
(defun origami-reset (buffer)