Let snippets expand in strings/comments by default

* yasnippet.el (yas-buffer-local-condition): Change default to t.
* doc/snippet-expansion.org: Update documentation.

doc/snippet-expansion.org

@@ -178,29 +178,26 @@ In particular, the following things matter:
                 (yas-activate-extra-mode 'rails-mode)))
 #+END_SRC
 
--  Buffer-local
-   [[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]]
-   variable
+-  Buffer-local [[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]] variable
 
    This variable provides finer grained control over what snippets can
-   be expanded in the current buffer. The default value won't let you
-   expand snippets inside comments or string literals for example. See
-   The condition system\_ for more info.
+   be expanded in the current buffer.  You could disable snippet
+   expansion inside comments or string literals for example.  See [[condition-system][the
+   condition system]] for more info.
 
-** The condition system
+** The condition system <<condition-system>>
 
 Consider this scenario: you are an old Emacs hacker. You like the
 abbrev-way and bind [[sym:yas-expand][=yas-expand=]] to =SPC=. However, you don't want
 =if= to be expanded as a snippet when you are typing in a comment
 block or a string (e.g. in =python-mode=).
 
-If you use the =# condition := directive (see
-[[./snippet-development.org][Writing Snippets]]) you could just specify
-the condition for =if= to be =(not (python-syntax-comment-or-string-p))=. But how
-about =while=, =for=, etc. ? Writing the same condition for all the
-snippets is just boring. So has a buffer local variable
-[[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]]. You can set this variable to
-=(not (python-syntax-comment-or-string-p))= in =python-mode-hook=.
+If you use the =# condition := directive (see [[./snippet-development.org][Writing Snippets]]) you
+could just specify the condition for =if= to be =(not
+(python-syntax-comment-or-string-p))=.  But how about =while=, =for=,
+etc?  Writing the same condition for all the snippets is just boring.
+So you can instead set [[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]] to =(not
+(python-syntax-comment-or-string-p))= in =python-mode-hook=.
 
 Then, what if you really want some particular snippet to expand even
 inside a comment?  Set [[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]] like this
@@ -214,10 +211,10 @@ inside a comment? Set [[sym:yas-buffer-local-condition][=yas-buffer-local-condit
                        t))))
 #+END_SRC
 
-... and specify the condition for a snippet that you're going to expand
-in comment to be evaluated to the symbol =force-in-comment=. Then it can
-be expanded as you expected, while other snippets like =if= still can't
-expanded in comment.
+... and for a snippet that you want to expand in comments, specify a
+condition which evaluates to the symbol =force-in-comment=.  Then it
+can be expanded as you expected, while other snippets like =if= still
+can't expanded in comments.
 
 For the full set of possible conditions, see the documentation for
 [[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]].

yasnippet.el

@@ -456,13 +456,7 @@ Attention: These hooks are not run when exiting nested/stacked snippet expansion
   '()
   "Hooks to run just before expanding a snippet.")
 
-(defvar yas-buffer-local-condition
-  '(if (and (let ((ppss (syntax-ppss)))
-              (or (nth 3 ppss) (nth 4 ppss)))
-            (memq this-command '(yas-expand yas-expand-from-trigger-key
-                                            yas-expand-from-keymap)))
-       '(require-snippet-condition . force-in-comment)
-     t)
+(defvar yas-buffer-local-condition t
   "Snippet expanding condition.
 
 This variable is a Lisp form which is evaluated every time a
@@ -509,12 +503,7 @@ conditions.
               (setq yas-buffer-local-condition
                     \\='(if (python-syntax-comment-or-string-p)
                          \\='(require-snippet-condition . force-in-comment)
-                       t))))
-
-The default value is similar, it filters out potential snippet
-expansions inside comments and string literals, unless the
-snippet itself contains a condition that returns the symbol
-`force-in-comment'.")
+                       t))))")
 
 
 ;;; Internal variables