cperl-mode: Improve detection of index entries for imenu

* lisp/progmodes/cperl-mode.el
(cperl-imenu-addback): Customization variable deleted.  This
variable has been declared obsolete in 1998.
(cperl--basic-identifier-regexp) and many other variables:
defining regular expressions for basic Perl constructs.
(cperl-imenu--create-perl-index): This function has been
completely rewritten, keeping only some parts of the output
formatting.  It now recognizes a lot more package and
subroutine declarations which came since Perl 5.14: Packages
with a version and/or a block attached, lexical subroutines,
declarations with a newline between the keyword "package" and
the package name, and several more.  This version also
correctly separates subroutine names from attributes, does no
longer support "unnamed" packages (which don't exist in Perl),
and doesn't fall for false positives like stuff that looks
like a declaration in a multiline string.
(cperl-tags-hier-init): Eliminate call to
`cperl-imenu-addback` (which actually was commented out in
1997)

* test/lisp/progmodes/cperl-mode-tests.el
(cperl-test--validate-regexp) and six other new tests for the
new regular expressions and the index creation.

* test/lisp/progmodes/cperl-mode-resources/grammar.pl: New
file showcasing different syntax variations for package and
sub declarations (bug#46574).

1 files changed, 95 insertions, 0 deletions

diff --git a/test/lisp/progmodes/cperl-mode-tests.el b/test/lisp/progmodes/cperl-mode-tests.el
index 943c454445c..61e4ece49b7 100644
--- a/test/lisp/progmodes/cperl-mode-tests.el
+++ b/test/lisp/progmodes/cperl-mode-tests.el
@@ -166,6 +166,101 @@ point in the distant past, and is still broken in perl-mode. "
                        (if (match-beginning 3) 0
                          perl-indent-level)))))))
 
+;;; Grammar based tests: unit tests
+
+(defun cperl-test--validate-regexp (regexp valid &optional invalid)
+  "Runs tests for elements of VALID and INVALID lists against REGEXP.
+Tests with elements from VALID must match, tests with elements
+from INVALID must not match.  The match string must be equal to
+the whole string."
+  (funcall cperl-test-mode)
+  (dolist (string valid)
+    (should (string-match regexp string))
+    (should (string= (match-string 0 string) string)))
+  (when invalid
+    (dolist (string invalid)
+       (should-not
+       (and (string-match regexp string)
+	    (string= (match-string 0 string) string))))))
+
+(ert-deftest cperl-test-ws-regexp ()
+  "Tests capture of very simple regular expressions (yawn)."
+  (let ((valid
+	 '(" " "\t" "\n"))
+	(invalid
+	 '("a" "  " "")))
+    (cperl-test--validate-regexp cperl--ws-regexp
+				 valid invalid)))
+
+(ert-deftest cperl-test-ws-or-comment-regexp ()
+  "Tests sequences of whitespace and comment lines."
+  (let ((valid
+	 `(" " "\t#\n" "\n# \n"
+	   ,(concat "# comment\n" "# comment\n" "\n" "#comment\n")))
+	(invalid
+	 '("=head1 NAME\n" )))
+    (cperl-test--validate-regexp cperl--ws-or-comment-regexp
+				 valid invalid)))
+
+(ert-deftest cperl-test-version-regexp ()
+  "Tests the regexp for recommended syntax of versions in Perl."
+  (let ((valid
+	 '("1" "1.1" "1.1_1" "5.032001"
+	   "v120.100.103"))
+	(invalid
+	 '("alpha" "0." ".123" "1E2"
+	   "v1.1" ; a "v" version string needs at least 3 components
+	   ;; bad examples from "Version numbers should be boring"
+	   ;; by xdg AKA David A. Golden
+	   "1.20alpha" "2.34beta2" "2.00R3")))
+    (cperl-test--validate-regexp cperl--version-regexp
+				 valid invalid)))
+
+(ert-deftest cperl-test-package-regexp ()
+  "Tests the regular expression of Perl package names with versions.
+Also includes valid cases with whitespace in strange places."
+  (let ((valid
+	 '("package Foo"
+	   "package Foo::Bar"
+	   "package Foo::Bar v1.2.3"
+	   "package Foo::Bar::Baz 1.1"
+	   "package \nFoo::Bar\n 1.00"))
+	(invalid
+	 '("package Foo;"          ; semicolon must not be included
+	   "package Foo 1.1 {"     ; nor the opening brace
+	   "packageFoo"            ; not a package declaration
+	   "package Foo1.1"        ; invalid package name
+	   "class O3D::Sphere")))  ; class not yet supported
+    (cperl-test--validate-regexp cperl--package-regexp
+				 valid invalid)))
+
+;;; Function test: Building an index for imenu
+
+(ert-deftest cperl-test-imenu-index ()
+  "Test index creation for imenu.
+This test relies on the specific layout of the index alist as
+created by CPerl mode, so skip it for Perl mode."
+  (skip-unless (eq cperl-test-mode #'cperl-mode))
+  (with-temp-buffer
+    (insert-file (ert-resource-file "grammar.pl"))
+    (cperl-mode)
+    (let ((index (cperl-imenu--create-perl-index))
+          current-list)
+      (setq current-list (assoc-string "+Unsorted List+..." index))
+      (should current-list)
+      (let ((expected '("(main)::outside"
+                        "Package::in_package"
+                        "Shoved::elsewhere"
+                        "Package::prototyped"
+                        "Versioned::Package::versioned"
+                        "Block::attr"
+                        "Versioned::Package::outer"
+                        "lexical"
+                        "Versioned::Block::signatured"
+                        "Package::in_package_again")))
+        (dolist (sub expected)
+          (should (assoc-string sub index)))))))
+
 ;;; Tests for issues reported in the Bug Tracker
 
 (defun cperl-test--run-bug-10483 ()