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elixir-smie.el
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elixir-smie.el
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(require 'smie)
(progn
(setq elixir-syntax-class-names nil)
(defmacro elixir-smie-define-regexp-opt (name &rest table)
`(elixir-smie-define-regexp ,name (regexp-opt (list ,@table))))
(defmacro elixir-smie-define-regexp (name regexp &optional flag)
(let ((regex-name (intern (format "elixir-smie-%s" name))))
`(progn
(defconst ,regex-name
,regexp)
(pushnew `(,',regex-name . ,(upcase (symbol-name ',name))) elixir-syntax-class-names))))
(elixir-smie-define-regexp-opt op
"<<<" ">>>" "^^^" "~~~" "&&&" "|||" ; op3
"===" "!==" ; comp3
"==" "!=" "<=" ">=" ; comp2
"{}" "[]" ; container2
"<" ">" ; comp1
"+" "-" "*" "/" "=" "|" "!" "^" "@" ; op1
"&&" "||" "<>" "++" "--" "**" "//" "::" "<-" ".." "/>" "=~" ; op2 (minus ->)
)
(elixir-smie-define-regexp dot "\\.")
(elixir-smie-define-regexp comma ",")
(elixir-smie-define-regexp -> "->")
(elixir-smie-define-regexp << "<<")
(elixir-smie-define-regexp >> ">>")
(elixir-smie-define-regexp-opt parens "(" ")" "{" "}" "[" "]" "<<" ">>"))
(defvar elixir-tokenizer-syntax-table (let ((table (copy-syntax-table elixir-mode-syntax-table)))
(modify-syntax-entry ?\n "." table)
table))
(setq elixir-smie-block-intro-keywords '(do else catch after rescue -> COMMA))
(defun elixir-smie-next-token-no-lookaround (forwardp nested)
;; First, skip comments but determine if newline-as-whitespace is
;; significant:
(with-syntax-table (if (and (not nested)
(member
(intern
(save-excursion
(elixir-smie-next-token-no-lookaround nil t)))
elixir-smie-block-intro-keywords))
elixir-mode-syntax-table
elixir-tokenizer-syntax-table)
(if forwardp
(forward-comment (point-max))
(forward-comment (- (point)))))
(let* ((found-token-class (find-if
(lambda (class-def)
(let ((regex (symbol-value (car class-def))))
(if forwardp
(looking-at regex)
(looking-back regex nil t))))
elixir-syntax-class-names))
(maybe-token (cond ((member (if forwardp
(following-char)
(preceding-char))
'(?\n ?\;))
(if forwardp
(forward-comment (point-max))
(forward-comment (- (point))))
";")
(found-token-class
(goto-char (if forwardp
(match-end 0)
(match-beginning 0)))
(if (string= "PARENS" (cdr found-token-class))
(buffer-substring-no-properties (match-beginning 0) (match-end 0))
(cdr found-token-class)))
((when (= ?\" (char-syntax (if forwardp
(following-char)
(preceding-char))))
(if forwardp
(forward-sexp)
(backward-sexp))
"STRING")))))
(or maybe-token
(downcase
(buffer-substring-no-properties
(point)
(if forwardp
(progn (skip-syntax-forward "'w_")
(point))
(progn (skip-syntax-backward "'w_")
(point))))))))
(defun elixir-smie-next-token (forwardp)
;; When reading match statements (the ones with expr -> statements),
;; we need to drop non-; delimiters so the parser knows when a
;; match statement ends and another begins, so scan around point to
;; see if there are any -> within the current block's scope.
;; If the current token is a ";", scan forward to see if the current
;; potential statement contains a "->". If so, scan back to find a
;; "do". If there is a -> there, emit a match-statement-delimiter
;; instead of the ";".
(let ((current-token (elixir-smie-next-token-no-lookaround forwardp nil)))
(if (and (string= ";" current-token)
;; Scan ahead:
(let ((level 0)
token)
(save-excursion
(block nil
(while (and (not (= (point) (point-max))) (not (string= "" token)) (not (string= ";" token)))
(setq token (elixir-smie-next-token-no-lookaround t nil))
(cond ((and (= level 0) (string= "->" token))
(return t))
((find token '("do" "fn") :test 'string=)
(incf level))
((string= token "end")
(decf level)))))))
;; Scan behind:
(let (token)
(save-excursion
(block nil
(while (and (not (= (point) (point-min))) (not (string= "" token)) (not (string= "do" token)) (not (string= "fn" token)))
(setq token (elixir-smie-next-token-no-lookaround nil nil))
(when (string= "->" token)
(return t)))
(when (or (string= token "do"))
t)))))
"MATCH-STATEMENT-DELIMITER"
current-token)))
(defun elixir-smie-forward-token ()
(elixir-smie-next-token t))
(defun elixir-smie-backward-token ()
(elixir-smie-next-token nil))
(setq elixir-smie-grammar
(smie-prec2->grammar
(smie-bnf->prec2
'((id)
(statements
(statement)
(statement ";" statements))
(statement
("if" non-block-expr "do" statements "else" statements "end")
("if" non-block-expr "do" statements "end")
("if" non-block-expr "COMMA" "do:" statement)
("if" non-block-expr "COMMA" "do:" statement "COMMA" "else:" statement)
("try" "do" statements "after" statements "end")
("try" "do" statements "catch" match-statements "end")
("try" "do" statements "rescue" match-statements "end")
("try" "do" statements "end")
("case" non-block-expr "do" match-statements "end")
("fn" match-statement "end")
("function" "do" match-statements "end")
(non-block-expr "do" statements "end")
(expr)
)
(non-block-expr
(non-block-expr "OP" non-block-expr)
(non-block-expr "DOT" non-block-expr)
(non-block-expr "COMMA" non-block-expr)
("(" statements ")")
("{" statements "}")
("[" statements "]")
("STRING"))
(match-statements
(match-statement "MATCH-STATEMENT-DELIMITER" match-statements)
(match-statement))
(match-statement
(non-block-expr "->" statements)))
'((assoc "DOT") (assoc "if") (assoc "do:") (assoc "else:") (assoc "COMMA") (assoc "OP") (assoc "->" ";")))))
(defvar elixir-smie-indent-basic 2)
(defun verbose-elixir-smie-rules (kind token)
(let ((value (elixir-smie-rules kind token)))
(message "%s '%s'; s:%s p:%s == %s" kind token (ignore-errors (smie-rule-sibling-p)) (ignore-errors smie--parent) value)
value))
(defun elixir-smie-rules (kind token)
(pcase (cons kind token)
(`(:elem . basic) elixir-smie-indent-basic)
(`(:after . "->")
(when (smie-rule-hanging-p)
elixir-smie-indent-basic))
(`(,_ . ,(or `"COMMA")) (smie-rule-separator kind))
(`(:after . "=") elixir-smie-indent-basic)
(`(:after . ,(or `"do"))
elixir-smie-indent-basic)
(`(:list-intro . ,(or `"do"))
t)))
(define-minor-mode elixir-smie-mode
"SMIE-based indentation and syntax for Elixir"
nil nil nil nil
(set (make-local-variable 'comment-start) "# ")
(set (make-local-variable 'comment-end) "")
(smie-setup elixir-smie-grammar 'elixir-smie-rules ; 'verbose-elixir-smie-rules
:forward-token 'elixir-smie-forward-token
:backward-token 'elixir-smie-backward-token))
(define-key elixir-mode-map (kbd "C-M-d") 'smie-down-list)
(provide 'elixir-smie)