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elm-indent.el
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elm-indent.el
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;;; elm-indent.el --- "semi-intelligent" indentation module for Elm Mode
;; Copyright 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
;; Copyright 1997-1998 Guy Lapalme
;; Copyright 2015 Bogdan Popa
;; Author: 1997-1998 Guy Lapalme <lapalme@iro.umontreal.ca>
;; This file is not part of GNU Emacs.
;; This file was adapted from `haskell-indent.el'.
;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 3, or (at your option)
;; any later version.
;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
(require 's)
(require 'cl-lib)
;;; Customizations
(defgroup elm-indent nil
"Elm indentation."
:group 'elm
:link '(custom-manual "(elm-mode)Indentation")
:prefix "elm-indent-")
(defcustom elm-indent-offset 4
"Indentation of Elm statements with respect to containing block."
:type 'integer
:group 'elm-indent)
(defcustom elm-indent-rhs-align-column 0
"Column on which to align right-hand sides (use 0 for ad-hoc alignment)."
:type 'integer
:group 'elm-indent)
(defcustom elm-indent-look-past-empty-line t
"If nil, indentation engine will not look past an empty line for layout points."
:group 'elm-indent
:type 'boolean)
(defcustom elm-indent-thenelse 0
"If non-zero, \"then\" and \"else\" are indented by that amount."
:group 'elm-indent
:type 'integer)
(defcustom elm-indent-after-keywords
`(("of" ,elm-indent-offset)
("in" ,elm-indent-offset 0)
("{" ,elm-indent-offset)
"if"
"then"
"else"
"let")
"Keywords after which indentation should be indented by some offset.
Each keyword info can have the following forms:
KEYWORD | (KEYWORD OFFSET [OFFSET-HANGING])
If absent OFFSET-HANGING defaults to OFFSET.
If absent OFFSET defaults to `elm-indent-offset'.
OFFSET-HANGING is the offset to use in the case where the keyword
is at the end of an otherwise-non-empty line."
:set-after '(elm-indent-offset)
:group 'elm-indent
:type '(repeat (choice string
(cons :tag "" (string :tag "keyword:")
(cons :tag "" (integer :tag "offset")
(choice (const nil)
(list :tag ""
(integer :tag "offset-pending"))))))))
(defcustom elm-indent-dont-hang '("(")
"Lexemes that should never be considered as hanging."
:group 'elm-indent
:type '(repeat string))
;;; Internals
(defconst elm-indent-start-keywords-re
(concat "\\<"
(regexp-opt '("module" "import" "type" "infix" "infixl" "infixr") t)
"\\>")
"Regexp for keywords to complete when standing at the first word of a line.")
(defvar elm-indent-off-side-keywords-re
(concat "\\<"
(regexp-opt '("let"))
"\\>[ \t]*"))
(defvar elm-indent-last-info nil)
(defvar elm-indent-info)
(defvar elm-indent-current-line-first-ident ""
"Global variable that keeps track of the first ident of the line to indent.")
(defvar elm-indent-inhibit-after-offset nil)
(defun elm-indent-point-to-col (apoint)
"Return the column number of APOINT."
(save-excursion
(goto-char apoint)
(current-column)))
(defun elm-indent-push-col (col &optional name)
"Push indentation information for the column COL.
The info is followed by NAME (if present).
Makes sure that the same indentation info is not pushed twice.
Uses free var `elm-indent-info'."
(let ((tmp (cons col name)))
(if (member tmp elm-indent-info)
elm-indent-info
(push tmp elm-indent-info))))
(defun elm-indent-push-pos (pos &optional name)
"Push indentation information for POS followed by NAME (if present)."
(elm-indent-push-col (elm-indent-point-to-col pos) name))
(defun elm-indent-column+offset (column offset)
(unless offset (setq offset elm-indent-offset))
(setq column (+ column offset)))
(defun elm-indent-push-pos-offset (pos &optional offset)
"Pushes indentation information for the column corresponding to POS
followed by an OFFSET (if present use its value otherwise use
`elm-indent-offset')."
(elm-indent-push-col (elm-indent-column+offset
(elm-indent-point-to-col pos)
offset)))
(defun elm-indent-empty-line-p ()
"Checks if the current line is empty; deals with Bird style scripts."
(save-excursion
(beginning-of-line)
(looking-at "[ \t]*$")))
(defun elm-indent-skip-blanks-and-newlines-forward (end)
"Skip forward blanks, tabs and newlines until END."
(skip-chars-forward " \t\n" end))
(defun elm-indent-skip-blanks-and-newlines-backward (start)
"Skip backward blanks, tabs and newlines up to START."
(skip-chars-backward " \t\n" start))
(defun elm-indent-start-of-def ()
"Return the position of the start of a definition.
The start of a def is expected to be recognizable by starting in column 0,
unless `elm-indent-look-past-empty-line' is nil, in which case we
take a coarser approximation and stop at the first empty line."
(save-excursion
(let ((start-code nil)
(top-col 0)
(save-point (point)))
;; determine the starting point of the current piece of code
(setq start-code (if start-code (1+ start-code) (point-min)))
;; go backward until the first preceding empty line
(forward-line -1)
(while (and (if elm-indent-look-past-empty-line
(or (> (current-indentation) top-col)
(elm-indent-empty-line-p))
(and (> (current-indentation) top-col)
(not (elm-indent-empty-line-p))))
(> (point) start-code)
(= 0 (forward-line -1))))
;; go forward after the empty line
(if (elm-indent-empty-line-p)
(forward-line 1))
(setq start-code (point))
;; find the first line of code which is not a comment
(forward-comment (point-max))
(if (> (point) save-point)
start-code
(point)))))
(defun elm-indent-open-structure (start end)
"If any structure (list or tuple) is not closed, between START and END,
returns the location of the opening symbol, nil otherwise."
(save-excursion
(nth 1 (parse-partial-sexp start end))))
(defun elm-indent-in-string (start end)
"If a string is not closed , between START and END, returns the
location of the opening symbol, nil otherwise."
(save-excursion
(let ((pps (parse-partial-sexp start end)))
(if (nth 3 pps) (nth 8 pps)))))
(defun elm-indent-in-comment (start end)
"Check, starting from START, if END is at or within a comment.
Returns the location of the start of the comment, nil otherwise."
(when (<= start end)
(let (pps)
(cond ((= start end) nil)
((nth 4 (save-excursion (setq pps (parse-partial-sexp start end))))
(nth 8 pps))
;; We also want to say that we are *at* the beginning of a comment.
((and (not (nth 8 pps))
(>= (point-max) (+ end 2))
(nth 4 (save-excursion
(setq pps (parse-partial-sexp end (+ end 2))))))
(nth 8 pps))))))
(defun elm-indent-type-at-point ()
"Return the type of the line (also puts information in `match-data')."
(cond
((elm-indent-empty-line-p) 'empty)
((elm-indent-in-comment (point-min) (point)) 'comment)
((looking-at "\\(\\([[:alpha:]]\\(\\sw\\|'\\)*\\)\\|_\\)[ \t\n]*") 'ident)
((looking-at "\\(|[^|]\\)[ \t\n]*") 'guard)
((looking-at "\\(=[^>=]\\|:[^:]\\|->\\|<-\\)[ \t\n]*") 'rhs)
(t 'other)))
(defun elm-indent-contour-line (start end)
"Generate contour information between START and END points."
(if (< start end)
(save-excursion
(goto-char end)
(elm-indent-skip-blanks-and-newlines-backward start)
(let ((cur-col (current-column)) ; maximum column number
(fl 0) ; number of lines that forward-line could not advance
contour)
(while (and (> cur-col 0) (= fl 0) (>= (point) start))
(back-to-indentation)
(if (< (point) start) (goto-char start))
(and (not (member (elm-indent-type-at-point)
'(empty comment))) ; skip empty and comment lines
(< (current-column) cur-col) ; less indented column found
(push (point) contour) ; new contour point found
(setq cur-col (current-column)))
(setq fl (forward-line -1)))
contour))))
(defun elm-indent-next-symbol (end)
"Move point to the next symbol."
(skip-syntax-forward ")" end)
(if (< (point) end)
(progn
(forward-sexp 1)
(elm-indent-skip-blanks-and-newlines-forward end))))
(defun elm-indent-next-symbol-safe (end)
"Puts point to the next following symbol.
If there are no more symbols in the sexp, puts point at END instead."
(condition-case errlist (elm-indent-next-symbol end)
(error (goto-char end))))
(defun elm-indent-separate-valdef (start end)
"Return a list of positions for important parts of a valdef."
(save-excursion
(let (valname valname-string aft-valname
guard aft-guard
rhs-sign aft-rhs-sign
type)
;; "parse" a valdef separating important parts
(goto-char start)
(setq type (elm-indent-type-at-point))
(if (or (memq type '(ident other))) ; possible start of a value def
(progn
(if (eq type 'ident)
(progn
(setq valname (match-beginning 0))
(setq valname-string (match-string 0))
(goto-char (match-end 0)))
(skip-chars-forward " \t" end)
(setq valname (point)) ; type = other
(elm-indent-next-symbol-safe end))
(while (and (< (point) end)
(setq type (elm-indent-type-at-point))
(or (memq type '(ident other))))
(if (null aft-valname)
(setq aft-valname (point)))
(elm-indent-next-symbol-safe end))))
(if (and (< (point) end) (eq type 'guard)) ; start of a guard
(progn
(setq guard (match-beginning 0))
(goto-char (match-end 0))
(while (and (< (point) end)
(setq type (elm-indent-type-at-point))
(not (eq type 'rhs)))
(if (null aft-guard)
(setq aft-guard (point)))
(elm-indent-next-symbol-safe end))))
(if (and (< (point) end) (eq type 'rhs)) ; start of a rhs
(progn
(setq rhs-sign (match-beginning 0))
(goto-char (match-end 0))
(if (< (point) end)
(setq aft-rhs-sign (point)))))
(list valname valname-string aft-valname
guard aft-guard rhs-sign aft-rhs-sign))))
(defsubst elm-indent-no-otherwise (guard)
"Check if there is no otherwise at GUARD."
(save-excursion
(goto-char guard)
(not (looking-at "|[ \t]*otherwise\\>"))))
(defsubst elm-indent-union-operator-p (guard)
"Check if there is a union operator at GUARD."
(save-excursion
(goto-char guard)
(and (looking-at "|")
(not (looking-at "|>")))))
(defun elm-indent-guard (start end end-visible indent-info)
"Find indentation information for a line starting with a guard."
(save-excursion
(let* ((elm-indent-info indent-info)
(sep (elm-indent-separate-valdef start end))
(valname (nth 0 sep))
(guard (nth 3 sep))
(rhs-sign (nth 5 sep)))
;; push information indentation for the visible part
(if (and guard (< guard end-visible) (elm-indent-no-otherwise guard))
(elm-indent-push-pos guard)
(if rhs-sign
(elm-indent-push-pos rhs-sign) ; probably within a data definition...
(if valname
(elm-indent-push-pos-offset valname))))
elm-indent-info)))
(defun elm-indent-rhs (start end end-visible indent-info)
"Find indentation information for a line starting with a rhs."
(save-excursion
(let* ((elm-indent-info indent-info)
(sep (elm-indent-separate-valdef start end))
(valname (nth 0 sep))
(guard (nth 3 sep))
(rhs-sign (nth 5 sep)))
;; push information indentation for the visible part
(if (and rhs-sign (< rhs-sign end-visible))
(elm-indent-push-pos rhs-sign)
(if (and guard (< guard end-visible))
(elm-indent-push-pos-offset guard)
(if valname ; always visible !!
(elm-indent-push-pos-offset valname))))
elm-indent-info)))
(defconst elm-indent-decision-table
(let ((or "\\)\\|\\("))
(concat "\\("
"1.1.11" or ; 1= vn gd rh arh
"1.1.10" or ; 2= vn gd rh
"1.1100" or ; 3= vn gd agd
"1.1000" or ; 4= vn gd
"1.0011" or ; 5= vn rh arh
"1.0010" or ; 6= vn rh
"110000" or ; 7= vn avn
"100000" or ; 8= vn
"001.11" or ; 9= gd rh arh
"001.10" or ;10= gd rh
"001100" or ;11= gd agd
"001000" or ;12= gd
"000011" or ;13= rh arh
"000010" or ;14= rh
"000000" ;15=
"\\)")))
(defun elm-indent-find-case (test)
"Find the index that matches TEST in the decision table."
(if (string-match elm-indent-decision-table test)
;; use the fact that the resulting match-data is a list of the form
;; (0 6 [2*(n-1) nil] 0 6) where n is the number of the matching regexp
;; so n= ((length match-data)/2)-1
(- (/ (length (match-data 'integers)) 2) 1)
(error "elm-indent-find-case: impossible case: %s" test)))
(defun elm-indent-after-list-item-p ()
(with-no-warnings
;; HACK: we depend on open being dynamically bound while handling
;; indentation inside of a parenthesized expression.
(when open
(or (eq (char-after open) ?\()
(eq (char-after open) ?\[)))))
(defun elm-indent-empty (start end end-visible indent-info)
"Find indentation points for an empty line."
(save-excursion
(let* ((elm-indent-info indent-info)
(sep (elm-indent-separate-valdef start end))
(valname (pop sep))
(valname-string (pop sep))
(aft-valname (pop sep))
(guard (pop sep))
(aft-guard (pop sep))
(rhs-sign (pop sep))
(aft-rhs-sign (pop sep))
(last-line (= end end-visible))
(test (string
(if valname ?1 ?0)
(if (and aft-valname (< aft-valname end-visible)) ?1 ?0)
(if (and guard (< guard end-visible)) ?1 ?0)
(if (and aft-guard (< aft-guard end-visible)) ?1 ?0)
(if (and rhs-sign (< rhs-sign end-visible)) ?1 ?0)
(if (and aft-rhs-sign (< aft-rhs-sign end-visible)) ?1 ?0))))
(if (and valname-string ; special case for start keywords
(string-match elm-indent-start-keywords-re valname-string))
(progn
(elm-indent-push-pos valname)
;; Special case for `type' declarations.
(if (string-match "\\<type\\>" valname-string)
(elm-indent-push-pos-offset valname)
(elm-indent-push-pos-offset valname 0)))
(pcase ; general case
(elm-indent-find-case test)
;; "1.1.11" 1= vn gd rh arh
(1 (elm-indent-push-pos valname)
(elm-indent-push-pos valname valname-string)
(if (elm-indent-no-otherwise guard) (elm-indent-push-pos guard "| "))
(elm-indent-push-pos aft-rhs-sign))
;; "1.1.10" 2= vn gd rh
(2 (elm-indent-push-pos valname)
(elm-indent-push-pos valname valname-string)
(if last-line
(elm-indent-push-pos-offset guard)
(if (elm-indent-no-otherwise guard) (elm-indent-push-pos guard "| "))))
;; "1.1100" 3= vn gd agd
(3 (elm-indent-push-pos valname)
(elm-indent-push-pos aft-guard)
(if last-line (elm-indent-push-pos-offset valname)))
;; "1.1000" 4= vn gd
(4 (elm-indent-push-pos valname)
(if last-line (elm-indent-push-pos-offset guard 2)))
;; "1.0011" 5= vn rh arh
(5 (elm-indent-push-pos valname)
(if (or (and aft-valname (= (char-after rhs-sign) ?\=))
(= (char-after rhs-sign) ?\:))
(elm-indent-push-pos valname valname-string))
(elm-indent-push-pos aft-rhs-sign))
;; "1.0010" 6= vn rh
(6 (elm-indent-push-pos valname)
(elm-indent-push-pos valname valname-string)
(if last-line (elm-indent-push-pos-offset valname)))
;; "110000" 7= vn avn
(7 (elm-indent-push-pos valname)
(elm-indent-push-pos-offset valname))
;; "100000" 8= vn
(8 (if (elm-indent-after-list-item-p)
(progn
(elm-indent-push-pos valname)
(elm-indent-push-pos-offset valname))
(elm-indent-push-pos valname)
(elm-indent-push-pos-offset valname)))
;; "001.11" 9= gd rh arh
(9 (if (elm-indent-no-otherwise guard) (elm-indent-push-pos guard "| "))
(elm-indent-push-pos aft-rhs-sign))
;; "001.10" 10= gd rh
(10 (if (elm-indent-no-otherwise guard) (elm-indent-push-pos guard "| "))
(if last-line (elm-indent-push-pos-offset guard)))
;; "001100" 11= gd agd
(11 (if (elm-indent-no-otherwise guard)
(if (elm-indent-union-operator-p guard)
(elm-indent-push-pos guard "| ")
(elm-indent-push-pos guard "|> ")))
(elm-indent-push-pos aft-guard))
;; "001000" 12= gd
(12 (if (elm-indent-no-otherwise guard) (elm-indent-push-pos guard "|> "))
(if last-line (elm-indent-push-pos-offset guard 2)))
;; "000011" 13= rh arh
(13 (elm-indent-push-pos aft-rhs-sign))
;; "000010" 14= rh
(14 (if last-line (elm-indent-push-pos-offset rhs-sign 2 )))
;; "000000" 15=
(_ (error "elm-indent-empty: %s impossible case" test ))))
elm-indent-info)))
(defun elm-indent-ident (start end end-visible indent-info)
"Find indentation points for a line starting with an identifier."
(save-excursion
(let*
((elm-indent-info indent-info)
(sep (elm-indent-separate-valdef start end))
(valname (pop sep))
(valname-string (pop sep))
(aft-valname (pop sep))
(guard (pop sep))
(aft-guard (pop sep))
(rhs-sign (pop sep))
(aft-rhs-sign (pop sep))
(last-line (= end end-visible))
(diff-first ; not a function def with the same name
(or (null valname-string)
(not (string= (s-trim valname-string)
(s-trim elm-indent-current-line-first-ident)))))
;; (is-type-def
;; (and rhs-sign (eq (char-after rhs-sign) ?\:)))
(test (string
(if valname ?1 ?0)
(if (and aft-valname (< aft-valname end-visible)) ?1 ?0)
(if (and guard (< guard end-visible)) ?1 ?0)
(if (and aft-guard (< aft-guard end-visible)) ?1 ?0)
(if (and rhs-sign (< rhs-sign end-visible)) ?1 ?0)
(if (and aft-rhs-sign (< aft-rhs-sign end-visible)) ?1 ?0))))
(if (and valname-string ; special case for start keywords
(string-match elm-indent-start-keywords-re valname-string))
(progn
(elm-indent-push-pos valname)
(if (string-match "\\<type\\>" valname-string)
;; Special case for `type' declarations.
(elm-indent-push-pos-offset valname)
(if (not (string-match
elm-indent-start-keywords-re
elm-indent-current-line-first-ident))
(elm-indent-push-pos-offset valname))))
(if (string= elm-indent-current-line-first-ident ":")
(if valname (elm-indent-push-pos valname))
(pcase ; general case
(elm-indent-find-case test)
;; "1.1.11" 1= vn gd rh arh
(1 (elm-indent-push-pos valname)
(if diff-first (elm-indent-push-pos aft-rhs-sign)))
;; "1.1.10" 2= vn gd rh
(2 (elm-indent-push-pos valname)
(if last-line
(elm-indent-push-pos-offset guard)))
;; "1.1100" 3= vn gd agd
(3 (elm-indent-push-pos valname)
(if diff-first
(elm-indent-push-pos aft-guard)))
;; "1.1000" 4= vn gd
(4 (elm-indent-push-pos valname)
(if last-line
(elm-indent-push-pos-offset guard 2)))
;; "1.0011" 5= vn rh arh
(5 (elm-indent-push-pos valname)
(if diff-first
(elm-indent-push-pos aft-rhs-sign)))
;; "1.0010" 6= vn rh
(6 (elm-indent-push-pos valname)
(elm-indent-push-pos valname valname-string)
(if last-line (elm-indent-push-pos-offset valname)))
;; "110000" 7= vn avn
(7 (elm-indent-push-pos valname)
(elm-indent-push-pos-offset valname))
;; "100000" 8= vn
(8 (elm-indent-push-pos valname)
(elm-indent-push-pos-offset valname))
;; "001.11" 9= gd rh arh
(9 (elm-indent-push-pos aft-rhs-sign))
;; "001.10" 10= gd rh
(10 (if last-line
(elm-indent-push-pos-offset guard)))
;; "001100" 11= gd agd
(11 (if (elm-indent-no-otherwise guard)
(elm-indent-push-pos aft-guard)))
;; "001000" 12= gd
(12 (if last-line (elm-indent-push-pos-offset guard 2)))
;; "000011" 13= rh arh
(13 (elm-indent-push-pos aft-rhs-sign))
;; "000010" 14= rh
(14 (if last-line (elm-indent-push-pos-offset rhs-sign 2)))
;; "000000" 15=
(_ (error "elm-indent-ident: %s impossible case" test )))))
elm-indent-info)))
(defun elm-indent-other (start end end-visible indent-info)
"Find indentation points for a non-empty line starting with something other
than an identifier, a guard or rhs."
(save-excursion
(let* ((elm-indent-info indent-info)
(sep (elm-indent-separate-valdef start end))
(valname (pop sep))
(valname-string (pop sep))
(aft-valname (pop sep))
(guard (pop sep))
(aft-guard (pop sep))
(rhs-sign (pop sep))
(aft-rhs-sign (pop sep))
(last-line (= end end-visible))
(test (string
(if valname ?1 ?0)
(if (and aft-valname (< aft-valname end-visible)) ?1 ?0)
(if (and guard (< guard end-visible)) ?1 ?0)
(if (and aft-guard (< aft-guard end-visible)) ?1 ?0)
(if (and rhs-sign (< rhs-sign end-visible)) ?1 ?0)
(if (and aft-rhs-sign (< aft-rhs-sign end-visible)) ?1 ?0))))
(if (and valname-string ; special case for start keywords
(string-match elm-indent-start-keywords-re valname-string))
(elm-indent-push-pos-offset valname)
(pcase ; general case
(elm-indent-find-case test)
;; "1.1.11" 1= vn gd rh arh
(1 (elm-indent-push-pos aft-rhs-sign))
;; "1.1.10" 2= vn gd rh
(2 (if last-line
(elm-indent-push-pos-offset guard)
(elm-indent-push-pos-offset rhs-sign 2)))
;; "1.1100" 3= vn gd agd
(3 (elm-indent-push-pos aft-guard))
;; "1.1000" 4= vn gd
(4 (elm-indent-push-pos-offset guard 2))
;; "1.0011" 5= vn rh arh
(5 (elm-indent-push-pos valname)
(elm-indent-push-pos aft-rhs-sign))
;; "1.0010" 6= vn rh
(6 (if last-line
(elm-indent-push-pos-offset valname)
(elm-indent-push-pos-offset rhs-sign 2)))
;; "110000" 7= vn avn
(7 (elm-indent-push-pos valname)
(elm-indent-push-pos-offset valname))
;; "100000" 8= vn
(8 (elm-indent-push-pos valname))
;; "001.11" 9= gd rh arh
(9 (elm-indent-push-pos aft-rhs-sign))
;; "001.10" 10= gd rh
(10 (if last-line
(elm-indent-push-pos-offset guard)
(elm-indent-push-pos-offset rhs-sign 2)))
;; "001100" 11= gd agd
(11 (if (elm-indent-no-otherwise guard)
(elm-indent-push-pos aft-guard)))
;; "001000" 12= gd
(12 (if last-line (elm-indent-push-pos-offset guard 2)))
;; "000011" 13= rh arh
(13 (elm-indent-push-pos aft-rhs-sign))
;; "000010" 14= rh
(14 (if last-line (elm-indent-push-pos-offset rhs-sign 2)))
;; "000000" 15=
(_ (error "elm-indent-other: %s impossible case" test ))))
elm-indent-info)))
(defun elm-indent-valdef-indentation (start end end-visible curr-line-type
indent-info)
"Find indentation information for a value definition."
(let ((elm-indent-info indent-info))
(if (< start end-visible)
(pcase curr-line-type
('empty (elm-indent-empty start end end-visible indent-info))
('ident (elm-indent-ident start end end-visible indent-info))
('guard (elm-indent-guard start end end-visible indent-info))
('rhs (elm-indent-rhs start end end-visible indent-info))
('comment (error "Comment indent should never happen"))
('other (elm-indent-other start end end-visible indent-info)))
elm-indent-info)))
(defun elm-indent-line-indentation (line-start line-end end-visible
curr-line-type indent-info)
"Compute indentation info between LINE-START and END-VISIBLE.
Separate a line of program into valdefs between offside keywords
and find indentation info for each part."
(save-excursion
;; point is (already) at line-start
(cl-assert (eq (point) line-start))
(let ((elm-indent-info indent-info)
(start (or (elm-indent-in-comment line-start line-end)
(elm-indent-in-string line-start line-end))))
(if start ; if comment at the end
(setq line-end start)) ; end line before it
;; loop on all parts separated by off-side-keywords
(while (and (re-search-forward elm-indent-off-side-keywords-re
line-end t)
(not (or (elm-indent-in-comment line-start (point))
(elm-indent-in-string line-start (point)))))
(let ((beg-match (match-beginning 0)) ; save beginning of match
(end-match (match-end 0))) ; save end of match
;; Do not try to find indentation points if off-side-keyword at
;; the start...
(if (or (< line-start beg-match)
;; Actually, if we're looking at a "let" inside a "do", we
;; should add the corresponding indentation point.
(eq (char-after beg-match) ?l))
(setq elm-indent-info
(elm-indent-valdef-indentation line-start beg-match
end-visible
curr-line-type
elm-indent-info)))
;; ...but keep the start of the line if keyword alone on the line
(if (= line-end end-match)
(elm-indent-push-pos beg-match))
(setq line-start end-match)
(goto-char line-start)))
(elm-indent-valdef-indentation line-start line-end end-visible
curr-line-type elm-indent-info))))
(defun elm-indent-layout-indent-info (start contour-line)
(let ((elm-indent-info nil)
(curr-line-type (elm-indent-type-at-point))
line-start line-end end-visible)
(save-excursion
(if (eq curr-line-type 'ident)
(let ; guess the type of line
((sep
(elm-indent-separate-valdef
(point) (line-end-position))))
;; if the first ident is the start of a def
;; keep it in a global variable
(setq elm-indent-current-line-first-ident
(if (nth 5 sep) ; is there a rhs-sign
(if (= (char-after (nth 5 sep)) ?\:) ;is it a typdef
":" (nth 1 sep))
""))))
(while contour-line ; explore the contour points
(setq line-start (pop contour-line))
(goto-char line-start)
(setq line-end (line-end-position))
(setq end-visible ; visible until the column of the
(if contour-line ; next contour point
(save-excursion
(move-to-column
(elm-indent-point-to-col (car contour-line)))
(point))
line-end))
(unless (or (elm-indent-open-structure start line-start)
(elm-indent-in-comment start line-start))
(setq elm-indent-info
(elm-indent-line-indentation line-start line-end
end-visible curr-line-type
elm-indent-info)))))
elm-indent-info))
(defun elm-indent-find-matching-start (regexp limit &optional pred start)
(let ((open (elm-indent-open-structure limit (point))))
(if open (setq limit (1+ open))))
(unless start (setq start (point)))
(when (re-search-backward regexp limit t)
(let ((nestedcase (match-end 1))
(outer (or (elm-indent-in-string limit (point))
(elm-indent-in-comment limit (point))
(elm-indent-open-structure limit (point))
(if (and pred (funcall pred start)) (point)))))
(cond
(outer
(goto-char outer)
(elm-indent-find-matching-start regexp limit pred start))
(nestedcase
;; Nested case.
(and (elm-indent-find-matching-start regexp limit pred)
(elm-indent-find-matching-start regexp limit pred start)))
(t (point))))))
(defun elm-indent-comment (open start)
"Compute indent info for comments and text inside comments.
OPEN is the start position of the comment in which point is."
;; Ideally we'd want to guess whether it's commented out code or
;; whether it's text. Instead, we'll assume it's text.
(save-excursion
(if (= open (point))
;; We're actually just in front of a comment: align with following
;; code or with comment on previous line.
(let ((prev-line-info
(cond
((eq (char-after) ?\{) nil) ;Align as if it were code.
((and (forward-comment -1)
(> (line-beginning-position 3) open))
;; We're after another comment and there's no empty line
;; between us.
(list (list (elm-indent-point-to-col (point)))))
(t nil)))) ;Else align as if it were code
;; Align with following code.
(forward-comment (point-max))
;; There are several possible indentation points for this code-line,
;; but the only valid indentation point for the comment is the one
;; that the user will select for the code-line. Obviously we can't
;; know that, so we just assume that the code-line is already at its
;; proper place.
;; Strictly speaking "assume it's at its proper place" would mean
;; we'd just use (current-column), but since this is using info from
;; lines further down and it's common to reindent line-by-line,
;; we'll align not with the current indentation, but with the
;; one that auto-indentation "will" select.
(append
prev-line-info
(let ((indent-info (save-excursion
(elm-indent-indentation-info start)))
(col (current-column)))
;; Sort the indent-info so that the current indentation comes
;; out first.
(setq indent-info
(sort indent-info
(lambda (x y)
(<= (abs (- col (car x))) (abs (- col (car y)))))))
indent-info)))
;; We really are inside a comment.
(if (looking-at "-}")
(progn
(forward-char 2)
(forward-comment -1)
(list (list (1+ (elm-indent-point-to-col (point))))))
(let ((offset (if (looking-at "--?")
(- (match-beginning 0) (match-end 0)))))
(forward-line -1) ;Go to previous line.
(back-to-indentation)
(if (< (point) start) (goto-char start))
(list (list (if (and comment-start-skip (looking-at comment-start-skip))
(if offset
(+ 2 offset (elm-indent-point-to-col (point)))
(elm-indent-point-to-col (match-end 0)))
(elm-indent-point-to-col (point))))))))))
(defun elm-indent-closing-keyword (start)
(let ((open (save-excursion
(elm-indent-find-matching-start
(pcase (char-after)
(?i "\\<\\(?:\\(in\\)\\|let\\)\\>")
(?o "\\<\\(?:\\(of\\)\\|case\\)\\>")
(?t "\\<\\(?:\\(then\\)\\|if\\)\\>")
(?e "\\<\\(?:\\(else\\)\\|if\\)\\>"))
start))))
;; For a "hanging let/case/if at EOL" we should use a different
;; indentation scheme.
(save-excursion
(goto-char open)
(if (elm-indent-hanging-p)
(setq open (elm-indent-virtual-indentation start))))
;; FIXME: we should try and figure out if the `if' is in a `do' layout
;; before using elm-indent-thenelse.
(list (list (+ (if (memq (char-after) '(?t ?e)) elm-indent-thenelse 0)
(elm-indent-point-to-col open))))))
(defun elm-indent-skip-lexeme-forward ()
(and (zerop (skip-syntax-forward "w"))
(skip-syntax-forward "_")
(skip-syntax-forward "(")
(skip-syntax-forward ")")))
(defun elm-indent-offset-after-info ()
"Return the info from `elm-indent-after-keywords' for keyword at point."
(let ((id (buffer-substring
(point)
(save-excursion
(elm-indent-skip-lexeme-forward)
(point)))))
(or (assoc id elm-indent-after-keywords)
(car (member id elm-indent-after-keywords)))))
(defun elm-indent-hanging-p ()
;; A Hanging keyword is one that's at the end of a line except it's not at
;; the beginning of a line.
(not (or (= (current-column) (current-indentation))
(save-excursion
(let ((lexeme
(buffer-substring
(point)
(progn (elm-indent-skip-lexeme-forward) (point)))))
(or (member lexeme elm-indent-dont-hang)
(> (line-end-position)
(progn (forward-comment (point-max)) (point)))))))))
(defun elm-indent-after-keyword-column (offset-info start &optional default)
(unless offset-info
(setq offset-info (elm-indent-offset-after-info)))
(unless default (setq default elm-indent-offset))
(setq offset-info
(if elm-indent-inhibit-after-offset '(0) (cdr-safe offset-info)))
(if (not (elm-indent-hanging-p))
(elm-indent-column+offset (current-column)
(or (car offset-info) default))
;; The keyword is hanging at the end of the line.
(elm-indent-column+offset
(elm-indent-virtual-indentation start)
(or (cadr offset-info) (car offset-info) default))))
(defun elm-indent-inside-paren-update-syntax-p (open)
(let ((end (point)))
(save-excursion
(goto-char open)
(and (not (looking-at ".*="))
(progn
(forward-line)
(elm-indent-skip-blanks-and-newlines-forward end)
(eq (char-after) ?\|))))))
(defun elm-indent-inside-paren (open)
;; there is an open structure to complete
(if (looking-at "\\s)\\|[|;,]")
;; A close-paren or a , or ; can only correspond syntactically to
;; the open-paren at `open'. So there is no ambiguity.
(let* ((is-close-brace (eq (char-after) ?\}))
(inside-update (elm-indent-inside-paren-update-syntax-p open)))
(if (and (eq (char-after) ?\;) (eq (char-after open) ?\())
(message "Mismatched punctuation: `%c' in %c...%c"
(char-after) (char-after open)
(if (eq (char-after open) ?\() ?\) ?\})))
(save-excursion
(goto-char open)
(list (list
(if (elm-indent-hanging-p)
(elm-indent-virtual-indentation nil)
(if (and inside-update
(not is-close-brace)
(eq (char-after open) ?\{))
(elm-indent-point-to-col (+ elm-indent-offset open))
(elm-indent-point-to-col open)))))))
;; There might still be layout within the open structure.
(let* ((end (point))
(basic-indent-info
;; Anything else than a ) is subject to layout.
(if (looking-at "\\s.\\|\\$ ")
(elm-indent-point-to-col open) ; align a punct with (
(let ((follow (save-excursion
(goto-char (1+ open))
(elm-indent-skip-blanks-and-newlines-forward end)
(point))))
(if (= follow end)
(save-excursion
(goto-char open)
(elm-indent-after-keyword-column nil nil 1))
(elm-indent-point-to-col (+ elm-indent-offset follow))))))
(open-column (elm-indent-point-to-col open))
(contour-line (elm-indent-contour-line (1+ open) end)))
(if (null contour-line)
(list (list basic-indent-info))
(let ((indent-info
(elm-indent-layout-indent-info
(1+ open) contour-line)))
;; Fix up indent info.
(let ((base-elem (assoc open-column indent-info)))
(if base-elem
(progn (setcar base-elem basic-indent-info)
(setcdr base-elem nil))
(if (not (eq basic-indent-info 0))
(setq indent-info (append (list (list basic-indent-info)) indent-info))
(setq indent-info (append indent-info (list (list basic-indent-info))))))
indent-info))))))
(defun elm-indent-virtual-indentation (start)
"Compute the \"virtual indentation\" of text at point.
The \"virtual indentation\" is the indentation that text at point would have
had, if it had been placed on its own line."
(let ((col (current-column))
(elm-indent-inhibit-after-offset (elm-indent-hanging-p)))
(if (save-excursion (skip-chars-backward " \t") (bolp))
;; If the text is indeed on its own line, than the virtual indent is
;; the current indentation.
col
;; Else, compute the indentation that it would have had.
(let ((info (elm-indent-indentation-info start))
(max -1))
;; `info' is a list of possible indent points. Each indent point is
;; assumed to correspond to a different parse. So we need to find
;; the parse that corresponds to the case at hand (where there's no
;; line break), which is assumed to always be the
;; deepest indentation.
(dolist (x info)
(setq x (car x))
;; Sometimes `info' includes the current indentation (or yet
;; deeper) by mistake, because elm-indent-indentation-info
;; wasn't designed to be called on a piece of text that is not at
;; BOL. So ignore points past `col'.
(if (and (> x max) (not (>= x col)))
(setq max x)))
;; In case all the indent points are past `col', just use `col'.
(if (>= max 0) max col)))))
(defun elm-indent-indentation-info (&optional start)
"Return a list of possible indentations for the current line.
These are then used by `elm-indent-cycle'.
START if non-nil is a presumed start pos of the current definition."
(unless start (setq start (elm-indent-start-of-def)))
(let (open contour-line)
(cond
;; in string?
((setq open (elm-indent-in-string start (point)))
(list (list (+ (elm-indent-point-to-col open)
(if (looking-at "\\\\") 0 1)))))
;; in comment ?
((setq open (elm-indent-in-comment start (point)))
(elm-indent-comment open start))
;; Closing the declaration part of a `let' or the test exp part of a case.
((looking-at "\\(?:in\\|of\\|then\\|else\\)\\>")
(elm-indent-closing-keyword start))
;; Right after a special keyword.
((save-excursion
(forward-comment (- (point-max)))
(when (and (not (zerop (skip-syntax-backward "w")))
(setq open (elm-indent-offset-after-info)))
(list (list (elm-indent-after-keyword-column open start))))))
;; open structure? ie ( { [
((setq open (elm-indent-open-structure start (point)))
(elm-indent-inside-paren open))
;; full indentation
((setq contour-line (elm-indent-contour-line start (point)))
(elm-indent-layout-indent-info start contour-line))