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Merge pull request #47 from MoisMoshev/main
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Implement indentation
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@andorsk
andorsk authored Jul 7, 2024
2 parents 6dc1ae9 + 9f2e3c1 commit 69374e0
Showing 1 changed file with 170 additions and 5 deletions.
175 changes: 170 additions & 5 deletions d2-mode.el
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Original file line number Diff line number Diff line change
Expand Up @@ -124,14 +124,178 @@
(org-babel-eval cmd "")
nil))

(defun d2--locate-declaration (str)
(defun d2--locate-declaration (str tag)
"Locate a certain declaration and return the line difference and indentation.
STR is the declaration."
STR is the declaration.
TAG is a symbol, which is prepended to the declaration data."
(let ((l (line-number-at-pos)))
(save-excursion
(if (re-search-backward str (point-min) t)
(cons (- l (line-number-at-pos)) (current-indentation))
(cons -1 -1)))))
(cons tag (cons (- l (line-number-at-pos)) (current-indentation)))
(cons tag (cons -1 -1))))))

(defun d2--combine-tokens-by-level (tokens)
"Combine TOKENS that are at the same level.
Collect the tags from both into a list.
Use the newer token's line and column."
(reverse
(cl-reduce (lambda (acc el)
(if (and (not (null acc))
(equal (d2--decl-line (car acc))
(d2--decl-line el)))
;; when tokens are on the same line, combine them
(progn
(setf (car acc)
;; we don't care about duplicate tags
(cons (cons (d2--decl-tag el) (d2--decl-tag (car acc)))
(cons (d2--decl-line el)
(d2--decl-column el))))
acc)
;; otherwise add a new token; set its tag to be a list
(cons (cons (list (d2--decl-tag el))
(cons (d2--decl-line el)
(d2--decl-column el)))
acc)))
tokens
:initial-value ())))

(defun d2--sort-tokens-by-line (tokens)
"Sort TOKENS by line number."
(sort tokens
(lambda (token1 token2)
(< (d2--decl-line token1)
(d2--decl-line token2)))))

(defun d2--filter-not-found-tokens (tokens)
"Filter TOKENS that were not detected.
They have a line number of -1"
(cl-remove-if
(lambda (token) (< (d2--decl-line token) 0))
tokens))

(defun d2--parse-from-line ()
"Parse by starting at current line and searching backward."
(let ((node (d2--locate-declaration
(rx (group (one-or-more (any alnum "_")))
(? (group ":"
(one-or-more space)))
(? (group
(one-or-more (not (any ?{ ?}))))))
'node))
(subnode-start (d2--locate-declaration
(rx (group (one-or-more (any alnum "_" "<->"
"->" "--" "<-"))
(? (group ":" (one-or-more space)))
(? (group (one-or-more (not (any ?{ ?})))))
"{"))
'subnode))
(end (d2--locate-declaration "^ *} *$"
'end))
(connection (d2--locate-declaration
(rx (group (one-or-more (any alnum "_" "-"))
(any "->"
"<->"
"--"
"<-")
(? (seq
":"
(one-or-more space)))
(? (one-or-more graph))))
'connection)))
(list node subnode-start end connection)))

;;; declaration part handling
(defun d2--decl-tag (decl)
"Get tag from the declaration DECL. It is the list head."
(car decl))
(defun d2--decl-line (decl)
"Get the text of the declaration DECL. It is the second item in the list."
(cadr decl))
(gv-define-setter d2--decl-line (val decl)
"Allow line VAL to be setf in declaration DECL."
`(setf (cadr ,decl) ,val))
(defun d2--decl-column (decl)
"Get the column number from DECL. It is the third item."
(cddr decl))
(defun d2--decl-tags-contain (decl tag)
"Check if any of the tags in DECL matches TAG."

Check failure on line 221 in d2-mode.el

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GitHub Actions / build (ubuntu-latest, 27.2) 

Probably "matches" should be imperative "match"

Check failure on line 221 in d2-mode.el

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GitHub Actions / build (windows-latest, 26.3) 

Probably "matches" should be imperative "match"
(seq-find (lambda (tag2)
(equal tag2 tag))
(d2--decl-tag decl)))

(defun d2--calculate-desired-indentation ()
"Calculate indentation of the current line.
Scan the tokens backwards and accumulate a list.
Only one token from each type is in this list.
To accommodate nested structures, we scan twice.
This way two tokens of the same type can be detected in sequence.
Once this information is collected, the indentation is chosen based
on the types of the current and previous token,
and the indentation of the previous line."
(save-excursion
(end-of-line)
;; sort tokens by line number (distance from current line)
;; and calculate the final indentation
(let* ((ordered-tokens (d2--combine-tokens-by-level
(d2--sort-tokens-by-line
(append (d2--filter-not-found-tokens (d2--parse-from-line))
;; also collect tokens starting at previous line
;; otherwise successive tokens of the same type
;; may not be detected
(if (equal (line-number-at-pos) 1)
()
(progn (forward-line -1)
(end-of-line)
(mapcar (lambda (token)
;; increment line number
;; to make it relative to starting line
(cl-incf (d2--decl-line token))
token)
(d2--filter-not-found-tokens
(d2--parse-from-line)))))))))
(current-token (car ordered-tokens))
(previous-token (cadr ordered-tokens)))
(message "tokens %s" (mapcar (lambda (token) (d2--decl-tag token)) ordered-tokens))
(cond ((and (d2--decl-tags-contain current-token 'node)
(null previous-token))
0)

((and (d2--decl-tags-contain current-token 'node)
(d2--decl-tags-contain previous-token 'subnode))
(+ 4 (d2--decl-column previous-token)))

((and (d2--decl-tags-contain current-token 'subnode)
(d2--decl-tags-contain previous-token 'subnode))
(+ 4 (d2--decl-column previous-token)))


((and (d2--decl-tags-contain current-token 'node)
(d2--decl-tags-contain previous-token 'node))
(d2--decl-column previous-token))

((and (d2--decl-tags-contain current-token 'node)
(d2--decl-tags-contain previous-token 'end))
(d2--decl-column previous-token))

((and (d2--decl-tags-contain current-token 'end)
(d2--decl-tags-contain previous-token 'end))
(max (- (d2--decl-column previous-token) 4) 0))

((and (d2--decl-tags-contain current-token 'end)
(d2--decl-tags-contain previous-token 'subnode))
(d2--decl-column previous-token))

((and (d2--decl-tags-contain current-token 'end)
(d2--decl-tags-contain previous-token 'node))
(max (- (d2--decl-column previous-token) 4) 0))

(t (progn (message "uknown syntax %s" current-token)
(d2--decl-column current-token)))))))

(defun d2-indent-line ()
"This is the actual function called by Emacs to indent."
(interactive)
(indent-line-to (d2--calculate-desired-indentation)))

(defun d2-compile ()
"Compile the current d2 file using d2."
Expand Down Expand Up @@ -222,7 +386,8 @@ Optional argument BROWSE whether to open the browser."
(setq-local font-lock-defaults '(d2-font-lock-keywords))
(setq-local comment-start "#")
(setq-local comment-end "")
(setq-local comment-start-skip "#"))
(setq-local comment-start-skip "#")
(setq-local indent-line-function 'd2-indent-line))

(provide 'd2-mode)

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