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dotemacs/rdfox-datalog-mode.el

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rdfox-datalog-mode.el
;;; rdfox-datalog-mode.el --- Major mode for editing RDFox Datalog files -*- lexical-binding: t; -*-
;; Author: Aleksandar Simic <a@repl.ist>
;; Keywords: languages, convenience
;; Version: 0.1.0
;; This file is NOT part of GNU Emacs.
;;; Commentary:
;;
;; A major mode for editing .dlog files.
;;
;; Features:
;; - Syntax highlighting for RDFox Datalog keywords, built-ins, variables,
;; IRIs, literals, and operators.
;; - # comments.
;; - Basic indentation.
;; - Automatic activation for .dlog files.
;;; Code:
(require 'rx)
(defgroup rdfox-datalog nil
"Major mode for RDFox Datalog files."
:group 'languages)
(defcustom rdfox-datalog-indent-offset 2
"Indentation width for `rdfox-datalog-mode'."
:type 'integer
:group 'rdfox-datalog)
(defconst rdfox-datalog--keywords
'("PREFIX" "NOT" "EXIST" "EXISTS" "IN" "FILTER" "BIND" "AS" "AGGREGATE" "ON"
"COUNT" "MIN" "MAX" "SUM" "AVG" "DISTINCT")
"Datalog keywords understood by the parser package.")
(defconst rdfox-datalog--builtins
'("CONCAT" "STR" "IF" "IRI" "SKOLEM" "ROUND" "REGEX")
"Built-in RDFox Datalog function names.")
(defconst rdfox-datalog-font-lock-keywords
`((,(rx symbol-start (regexp (regexp-opt rdfox-datalog--keywords t)) symbol-end)
. font-lock-keyword-face)
(,(rx symbol-start (regexp (regexp-opt rdfox-datalog--builtins t)) symbol-end)
. font-lock-builtin-face)
(,(rx symbol-start (or "true" "false") symbol-end)
. font-lock-constant-face)
(,(rx "?" (one-or-more (or word ?_)))
. font-lock-variable-name-face)
(,(rx "_:" (one-or-more (or word ?_)))
. font-lock-constant-face)
(,(rx "<" (zero-or-more (not (any "\n" ">"))) ">")
. font-lock-constant-face)
(,(rx symbol-start
(one-or-more (or word ?_))
":"
(one-or-more (or word ?_))
symbol-end)
. font-lock-constant-face)
(,(rx symbol-start
(or ":"
(seq (one-or-more (or word ?_)) ":"))
symbol-end)
. font-lock-constant-face)
(,(rx ":" (one-or-more (or word ?_)))
. font-lock-constant-face)
(,(rx (or ":-" "!=" "<=" ">=" "&&" "||"))
. font-lock-keyword-face)
(,(rx symbol-start
(optional (any "+" "-"))
(one-or-more digit)
(optional "." (zero-or-more digit))
(optional (any "e" "E") (optional (any "+" "-")) (one-or-more digit))
symbol-end)
. font-lock-constant-face))
"Font lock rules for `rdfox-datalog-mode'.")
(defvar rdfox-datalog-mode-syntax-table
(let ((st (make-syntax-table)))
;; # comments
(modify-syntax-entry ?# "<" st)
(modify-syntax-entry ?\n ">" st)
;; Strings
(modify-syntax-entry ?\" "\"" st)
(modify-syntax-entry ?' "\"" st)
;; Word constituents for common Datalog tokens.
(modify-syntax-entry ?? "_" st)
(modify-syntax-entry ?_ "w" st)
(modify-syntax-entry ?: "_" st)
st)
"Syntax table for `rdfox-datalog-mode'.")
(defun rdfox-datalog-syntax-propertize (start end)
"Prevent comment syntax from applying to # inside IRI refs between START and END."
(save-excursion
(goto-char start)
(remove-text-properties start end '(syntax-table nil))
(while (re-search-forward "<[^>\n]*>" end t)
(let ((iri-start (match-beginning 0))
(iri-end (match-end 0)))
(save-excursion
(goto-char iri-start)
(while (search-forward "#" iri-end t)
(put-text-property (1- (point))
(point)
'syntax-table
(string-to-syntax "."))))))))
(defun rdfox-datalog--previous-significant-line ()
"Move point to previous non-empty, non-comment line.
Return point if found, otherwise nil."
(catch 'found
(while (zerop (forward-line -1))
(back-to-indentation)
(unless (or (eolp) (looking-at-p "#"))
(throw 'found (point))))
nil))
(defun rdfox-datalog--line-starts-with-closing-delimiter-p ()
"Return non-nil if current line starts with a closing delimiter or terminal dot."
(save-excursion
(back-to-indentation)
(looking-at-p (rx (or ")" "]" ".")))))
(defun rdfox-datalog--previous-line-opens-body-p ()
"Return non-nil if the previous significant line opens a continuation block."
(save-excursion
(when (rdfox-datalog--previous-significant-line)
(end-of-line)
(skip-chars-backward " \t")
(or (looking-back ":-" (line-beginning-position))
(looking-back "[][(),]$" (line-beginning-position))
(looking-back ",$" (line-beginning-position))))))
(defun rdfox-datalog-compute-indentation ()
"Compute indentation for the current line."
(save-excursion
(back-to-indentation)
(cond
((bobp) 0)
((rdfox-datalog--line-starts-with-closing-delimiter-p)
(when (ignore-errors (backward-up-list) t)
(current-indentation)))
((rdfox-datalog--previous-line-opens-body-p)
(+ (save-excursion
(rdfox-datalog--previous-significant-line)
(current-indentation))
rdfox-datalog-indent-offset))
(t
(or (save-excursion
(when (rdfox-datalog--previous-significant-line)
(current-indentation)))
0)))))
(defun rdfox-datalog-indent-line ()
"Indent current line for `rdfox-datalog-mode'."
(interactive)
(let ((indent (rdfox-datalog-compute-indentation))
(offset (- (current-column) (current-indentation))))
(indent-line-to (max indent 0))
(when (> offset 0)
(move-to-column (+ indent offset)))))
;;;###autoload
(define-derived-mode rdfox-datalog-mode prog-mode "RDFox-Datalog"
"Major mode for editing RDFox Datalog files."
:syntax-table rdfox-datalog-mode-syntax-table
(setq-local font-lock-defaults '(rdfox-datalog-font-lock-keywords))
(setq-local syntax-propertize-function #'rdfox-datalog-syntax-propertize)
(setq-local comment-start "#")
(setq-local comment-end "")
(setq-local indent-line-function #'rdfox-datalog-indent-line)
(setq-local indent-tabs-mode nil))
;;;###autoload
(add-to-list 'auto-mode-alist '("\\.dlog\\'" . rdfox-datalog-mode))
(provide 'rdfox-datalog-mode)
;;; rdfox-datalog-mode.el ends here
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