branch: elpa/haskell-tng-mode
commit 96609e4b9a4b8572c0527dde20657434dbabd4ac
Author: Tseen She <ts33n....@gmail.com>
Commit: Tseen She <ts33n....@gmail.com>
thoughts on layout inference
---
haskell-tng-smie.el | 41 +++++++++++++++++++++++++++++------------
test/lexer/layout.hs.lexer | 4 ++--
2 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/haskell-tng-smie.el b/haskell-tng-smie.el
index 576a783..67ac14d 100644
--- a/haskell-tng-smie.el
+++ b/haskell-tng-smie.el
@@ -46,17 +46,27 @@
(case-fold-search nil)
(syntax (char-syntax (char-after))))
(cond
- ;; TODO brace inference
- ((and
- (not (eq start-line this-line))
- (<=
- (haskell-tng-smie:indentation-level (point))
- (haskell-tng-smie:indentation-level start))
- ";"))
+ ;; layout: semicolon inference
+ ((not (eq start-line this-line))
+ (let ((start-layout (haskell-tng-smie:layout-level start-line))
+ (this-layout (current-indentation)))
+ (cond
+ ((null start-layout) ""
+ (eq start-layout this-layout) ";"
+ t ""))))
;; parens
((member syntax '(?\( ?\) ?\" ?$)) nil)
+ ;; TODO brace inference ("offside" rule).
+ ;;
+ ;; Starting braces are trivial, there is a known list of keywords, so
+ ;; we just need to do a lookback when we hit a non-{ lexeme. Ending
+ ;; braces are a lot harder, as we need to calculate "do we need to
+ ;; close a brace here" every time the indentation level decreases. A
+ ;; possible solution is to calculate and cache the closing brace when
+ ;; discovering an open brace, but that just introduces more problems.
+
;; regexps
((or
;; known identifiers
@@ -68,12 +78,19 @@
(goto-char (match-end 0))
(match-string-no-properties 0)))))))
-(defun haskell-tng-smie:indentation-level (p)
- "Calculates the indentation level of the most inner part of the given
point's line."
- ;; FIXME this is a hack for now, look for `let', `do' and friends according
to
- ;; the Haskell2010 report.
+(defun haskell-tng-smie:layout-level (line)
+ "Calculates the layout indentation of the most inner part of
+the given point's line."
+ ;; FIXME should the input be the line numbers?
+ ;;
+ ;; TODO starting at the end of the line, look backwards for wldo (where,
let, do, of).
+ ;; If the wldo is the last lexeme, then the layout level is set by the next
line (return nil).
+ ;; If the wldo is followed by a non-brace lexeme, set the layout level.
+ ;;
+ ;; If there is no wldo, the layout level is set by the indentation level
+ ;; (think about this some more)
(save-excursion
- (goto-char p)
+ (goto-line line)
(current-indentation)))
;; TODO a haskell grammar
diff --git a/test/lexer/layout.hs.lexer b/test/lexer/layout.hs.lexer
index d048eb2..f76687b 100644
--- a/test/lexer/layout.hs.lexer
+++ b/test/lexer/layout.hs.lexer
@@ -64,8 +64,8 @@ where
stkToLst
Empty
=
-[
-]
+SYNTAX_[
+SYNTAX_]
;
stkToLst
SYNTAX_(
