On Sat, Feb 13 2021, Adam Spiers wrote: > Add a diff driver which recognises Elisp top-level forms and outline > headings for display in hunk headers, and which correctly renders word > diffs. Neat, I for one would find this useful. > This approach was previously discussed on the emacs-devel mailing list: > > https://lists.gnu.org/archive/html/emacs-devel/2021-02/msg00705.html > > * userdiff.c (builtin_drivers): Provide regexen for Elisp top level > forms and outline headings, and for word diffs. > * t/t4018-diff-funcname.sh (diffpatterns): Add test for elisp driver > * t/t4018/elisp-outline-heading: Test fixture for outline headings > * t/t4018/elisp-top-level-form: Test fixture for top level forms > * t/t4034-diff-words.sh: Add test for elisp driver > * t/t4034/elisp/*: Test fixtures for word diffs Please no on the overly verbose emacs.git convention of per-file changelogs in commit messages :) > diff --git a/t/t4018/elisp-outline-heading b/t/t4018/elisp-outline-heading > new file mode 100644 > index 0000000000..c13bdafafe > --- /dev/null > +++ b/t/t4018/elisp-outline-heading > @@ -0,0 +1,6 @@ > +;;; A top-level outline heading > +;;;; A second-level outline heading RIGHT > + > +;; This is a ChangeMe comment outside top-level forms > +(defun foo () > + (bar 1 2 3) > diff --git a/t/t4018/elisp-top-level-form b/t/t4018/elisp-top-level-form > new file mode 100644 > index 0000000000..683f7ffcf1 > --- /dev/null > +++ b/t/t4018/elisp-top-level-form > @@ -0,0 +1,7 @@ > +;;; Outline heading > + > +;; This is a comment > +(RIGHT > + (list 1 2 3) > + ChangeMe > + (list a b c)) > diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh > index 0c8fb39ced..a546ee831a 100755 > --- a/t/t4034-diff-words.sh > +++ b/t/t4034-diff-words.sh > @@ -315,6 +315,7 @@ test_language_driver cpp > test_language_driver csharp > test_language_driver css > test_language_driver dts > +test_language_driver elisp > test_language_driver fortran > test_language_driver html > test_language_driver java > diff --git a/t/t4034/elisp/expect b/t/t4034/elisp/expect > new file mode 100644 > index 0000000000..29a6ef2520 > --- /dev/null > +++ b/t/t4034/elisp/expect > @@ -0,0 +1,9 @@ > +<BOLD>diff --git a/pre b/post<RESET> > +<BOLD>index 4a39df8..6619e96 100644<RESET> > +<BOLD>--- a/pre<RESET> > +<BOLD>+++ b/post<RESET> > +<CYAN>@@ -1,4 +1,4 @@<RESET> > +(defun <RED>myfunc<RESET><GREEN>my-func<RESET> (<RED>a b<RESET><GREEN>first second<RESET>) > + "This is a <RED>really<RESET><GREEN>(moderately)<RESET> cool function." > + (let ((c (<RED>+ a b<RESET><GREEN>1+ first<RESET>))) > + (format "one more than the total is %d" (<RED>1+<RESET><GREEN>+<RESET> c <GREEN>second<RESET>)))) > diff --git a/t/t4034/elisp/post b/t/t4034/elisp/post > new file mode 100644 > index 0000000000..6619e96657 > --- /dev/null > +++ b/t/t4034/elisp/post > @@ -0,0 +1,4 @@ > +(defun my-func (first second) > + "This is a (moderately) cool function." > + (let ((c (1+ first))) > + (format "one more than the total is %d" (+ c second)))) > diff --git a/t/t4034/elisp/pre b/t/t4034/elisp/pre > new file mode 100644 > index 0000000000..4a39df8ffb > --- /dev/null > +++ b/t/t4034/elisp/pre > @@ -0,0 +1,4 @@ > +(defun myfunc (a b) > + "This is a really cool function." > + (let ((c (+ a b))) > + (format "one more than the total is %d" (1+ c)))) > diff --git a/userdiff.c b/userdiff.c > index 3f81a2261c..292e51674a 100644 > --- a/userdiff.c > +++ b/userdiff.c > @@ -53,6 +53,15 @@ PATTERNS("dts", > /* Property names and math operators */ > "[a-zA-Z0-9,._+?#-]+" > "|[-+*/%&^|!~]|>>|<<|&&|\\|\\|"), > +PATTERNS("elisp", > + /* Top level forms and outline headings */ > + "^((\\(|;;;+ +).+)", > + /* > + * Emacs Lisp allows symbol names containing any characters. > + * However spaces within the symbol must be escaped. > + */ > + "(\\.|[^ ()])+" > + ), > PATTERNS("elixir", > "^[ \t]*((def(macro|module|impl|protocol|p)?|test)[ \t].*)$", > /* -- */ I think this patch would benefit from first being dogfooded in the emacs-devel community. There's an existing regex in emacs.git's autoconf.sh which anyone developing emacs.git is using. If you run: diff -u <(git -c diff.elisp.xfuncname='^\(def[^[:space:]]+[[:space:]]+([^()[:space:]]+)' log -p -- lisp | grep -m 100 @@) \ <(git -c diff.elisp.xfuncname='^((\(|;;;+ +).*)$' log -p -- lisp | grep -m 100 @@) \ | less You can see how it differs from yours, and that also neatly answers the question[1] you had in the linked thread about why these patterns tend to be explicitly scoped to how you define a function/package/whatever in the language in question. Just a cursory "git log -p -- lisp" in emacs.git with your patch shows e.g. lisp/thingatpt.el where forms in a "defun" aren't indented (before it selects the "defun", after with yours it's a "put" in the middle of the function). Yours also changes it from e.g.: @@ -61,7 +61,7 @@ forward-thing to: @@ -61,7 +61,7 @@ (defun forward-thing (thing &optional n) Is this really desired in elisp? I also note how our tests in t4018-diff-funcname.sh are really bad in not testing for this at all. I.e. we just test that we match the right line, not how we extract a match from it. 1. https://lists.gnu.org/archive/html/emacs-devel/2021-02/msg00739.html
