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What's the most reliable way to get the start and end positions of the symbol at the cursor location (point)?

Drew
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Saddle Point
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2 Answers2

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The thingatpt.el API works as follows:

(thing-at-point 'symbol) ;=> foo
(beginning-of-thing 'symbol) ;=> 42
(end-of-thing 'symbol) ;=> 45
(bounds-of-thing-at-point 'symbol) ;=> (42 . 45)

While it's not 100% reliable as it relies on (forward-thing 'symbol) to do the right thing, it's pretty good and one of the better APIs in Emacs. Give it a try!

wasamasa
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  • Note that, unless someone takes steps to make it do otherwise, `(forward-thing 'symbol)` calls `forward-symbol` which certainly does the right thing in terms of the buffer's syntax table and the syntax-based definition of "symbol". – phils Jun 21 '17 at 13:00
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I would expect symbol-at-point to be reliable.

Given that you yourself tagged this question with thing-at-point, are you asking in particular whether there are flaws with this method?

phils
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  • `symbol-at-point` or `thing-at-point` returns current symbol at point, but I'd like to get the start/end `point`(the exact boundary) of this symbol... – Saddle Point Jun 21 '17 at 11:43
  • Oh yes. I ought to have said `(bounds-of-thing-at-point 'symbol)`. But the same question applies -- you *seem* to already be aware of `thing-at-point` (and hence the `thingatpt.el` library in general), so are you specifically questioning its reliability, or was it simply that you hadn't noticed the function in question? – phils Jun 21 '17 at 12:39
  • I hadn't noticed the function, though I use `thing-at-point` quite often ...And as @wasamasa pointed out, the function may not be 100% reliable, though I've not encountered such situations. Thanks for you information. – Saddle Point Jun 21 '17 at 12:52
  • I've run into it being unreliable with Evil and other modes doing weird things, see https://github.com/emacs-evil/evil/issues/844 for example. – wasamasa Jun 21 '17 at 16:46
  • That particular instance sounds like an issue with the evil library's thing-at-point handler(s) for `evil-defun` rather than `symbol`, though? I would expect the handling of `symbol` to be reliable. For the standard "things" I would expect this to be as reliable as other methods for obtaining the same information (but certainly there may be bugs for more complex "things" where the behaviour may be down to individual modes to define). – phils Jun 21 '17 at 22:07