[nongnu] elpa/lua-mode b37710e 418/468: Enable fontification of variable names in "for" and function parameters

[Philip Kaludercic]

branch: elpa/lua-mode
commit b37710e474a805a9a5a7f5b25a084277c73b7fb3
Author: immerrr <immerrr+lua@gmail.com>
Commit: immerrr <immerrr+lua@gmail.com>

    Enable fontification of variable names in "for" and function parameters
    
    - drop make-delimited-matcher magical function
    
    - add regression test for issue #163
---
 lua-mode.el            | 180 ++++++++++++++++++-------------------------------
 test/test-font-lock.el |  67 ++++++++++++++----
 2 files changed, 119 insertions(+), 128 deletions(-)

diff --git a/lua-mode.el b/lua-mode.el
index f1640b9..4b682d6 100644
--- a/lua-mode.el
+++ b/lua-mode.el
@@ -138,7 +138,17 @@
            (lua-keyword
             (symbol "break" "do" "else" "elseif" "end"  "for" "function"
                     "goto" "if" "in" "local" "repeat" "return"
-                    "then" "until" "while"))))
+                    "then" "until" "while"))
+           (lua-up-to-9-variables
+            (seq (group-n 1 lua-name) ws
+                 (? "," ws (group-n 2 lua-name) ws
+                    (? "," ws (group-n 3 lua-name) ws
+                       (? "," ws (group-n 4 lua-name) ws
+                          (? "," ws (group-n 5 lua-name) ws
+                             (? "," ws (group-n 6 lua-name) ws
+                                (? "," ws (group-n 7 lua-name) ws
+                                   (? "," ws (group-n 8 lua-name) ws
+                                      (? "," ws (group-n 9 lua-name) 
ws))))))))))))
 
         (defmacro lua-rx (&rest regexps)
           (eval `(rx-let ,lua--rx-bindings
@@ -223,7 +233,17 @@ element is itself expanded with `lua-rx-to-string'. "
               (lua-keyword
                :rx (symbol "break" "do" "else" "elseif" "end"  "for" "function"
                            "goto" "if" "in" "local" "repeat" "return"
-                           "then" "until" "while")))))))
+                           "then" "until" "while"))
+              (lua-up-to-9-variables
+               :rx (seq (group-n 1 lua-name) ws
+                        (? "," ws (group-n 2 lua-name) ws
+                           (? "," ws (group-n 3 lua-name) ws
+                              (? "," ws (group-n 4 lua-name) ws
+                                 (? "," ws (group-n 5 lua-name) ws
+                                    (? "," ws (group-n 6 lua-name) ws
+                                       (? "," ws (group-n 7 lua-name) ws
+                                          (? "," ws (group-n 8 lua-name) ws
+                                             (? "," ws (group-n 9 lua-name) 
ws)))))))))))))))
 
 
 ;; Local variables
@@ -534,86 +554,6 @@ traceback location."
 This is a compilation of 5.1, 5.2 and 5.3 builtins taken from the
 index of respective Lua reference manuals.")
 
-(eval-and-compile
-  (defun lua-make-delimited-matcher (elt-regexp sep-regexp end-regexp)
-    "Construct matcher function for `font-lock-keywords' to match a sequence.
-
-It's supposed to match sequences with following EBNF:
-
-ELT-REGEXP { SEP-REGEXP ELT-REGEXP } END-REGEXP
-
-The sequence is parsed one token at a time.  If non-nil is
-returned, `match-data' will have one or more of the following
-groups set according to next matched token:
-
-1. matched element token
-2. unmatched garbage characters
-3. misplaced token (i.e. SEP-REGEXP when ELT-REGEXP is expected)
-4. matched separator token
-5. matched end token
-
-Blanks & comments between tokens are silently skipped.
-Groups 6-9 can be used in any of argument regexps."
-    (let*
-        ((delimited-matcher-re-template
-          
"\\=\\(?2:.*?\\)\\(?:\\(?%s:\\(?4:%s\\)\\|\\(?5:%s\\)\\)\\|\\(?%s:\\(?1:%s\\)\\)\\)")
-         ;; There's some magic to this regexp. It works as follows:
-         ;;
-         ;; A. start at (point)
-         ;; B. non-greedy match of garbage-characters (?2:)
-         ;; C. try matching separator (?4:) or end-token (?5:)
-         ;; D. try matching element (?1:)
-         ;;
-         ;; Simple, but there's a trick: pt.C and pt.D are embraced by one more
-         ;; group whose purpose is determined only after the template is
-         ;; formatted (?%s:):
-         ;;
-         ;; - if element is expected, then D's parent group becomes "shy" and 
C's
-         ;;   parent becomes group 3 (aka misplaced token), so if D matches 
when
-         ;;   an element is expected, it'll be marked with warning face.
-         ;;
-         ;; - if separator-or-end-token is expected, then it's the opposite:
-         ;;   C's parent becomes shy and D's will be matched as misplaced 
token.
-         (elt-expected-re (format delimited-matcher-re-template
-                                  3 sep-regexp end-regexp "" elt-regexp))
-         (sep-or-end-expected-re (format delimited-matcher-re-template
-                                         "" sep-regexp end-regexp 3 
elt-regexp)))
-
-      (lambda (end)
-        (let* ((prev-elt-p (match-beginning 1))
-               (prev-end-p (match-beginning 5))
-
-               (regexp (if prev-elt-p sep-or-end-expected-re elt-expected-re))
-               (comment-start (lua-comment-start-pos (syntax-ppss)))
-               (parse-stop end))
-
-          ;; If token starts inside comment, or end-token was encountered, 
stop.
-          (when (and (not comment-start)
-                     (not prev-end-p))
-            ;; Skip all comments & whitespace. forward-comment doesn't have 
boundary
-            ;; argument, so make sure point isn't beyond parse-stop afterwards.
-            (while (and (< (point) end)
-                        (forward-comment 1)))
-            (goto-char (min (point) parse-stop))
-
-            ;; Reuse comment-start variable to store beginning of comment that 
is
-            ;; placed before line-end-position so as to make sure token search 
doesn't
-            ;; enter that comment.
-            (setq comment-start
-                  (lua-comment-start-pos
-                   (save-excursion
-                     (parse-partial-sexp (point) parse-stop
-                                         nil nil nil 'stop-inside-comment)))
-                  parse-stop (or comment-start parse-stop))
-
-            ;; Now, let's match stuff.  If regular matcher fails, declare a 
span of
-            ;; non-blanks 'garbage', and the next iteration will start from 
where the
-            ;; garbage ends.  If couldn't match any garbage, move point to the 
end
-            ;; and return nil.
-            (or (re-search-forward regexp parse-stop t)
-                (re-search-forward "\\(?1:\\(?2:[^ \t]+\\)\\)" parse-stop 
'skip)
-                (prog1 nil (goto-char end)))))))))
-
 
 (defvar lua-font-lock-keywords
   `(;; highlight the hash-bang line "#!/foo/bar/lua" as comment
@@ -641,42 +581,50 @@ Groups 6-9 can be used in any of argument regexps."
     (,lua--builtins
      (1 font-lock-builtin-face) (2 font-lock-builtin-face nil noerror))
 
-    ("^[ \t]*\\_<for\\_>"
-     (,(lua-make-delimited-matcher (lua-rx lua-name) ","
-                                   (lua-rx (or (symbol "in") 
lua-assignment-op)))
-      nil nil
-      (1 font-lock-variable-name-face nil noerror)
-      (2 font-lock-warning-face t noerror)
-      (3 font-lock-warning-face t noerror)))
-
-    ;; Handle local variable/function names
-    ;;  local blalba, xyzzy =
-    ;;        ^^^^^^  ^^^^^
-    ;;
-    ;;  local function foobar(x,y,z)
-    ;;                 ^^^^^^
-    ;;  local foobar = function(x,y,z)
-    ;;        ^^^^^^
-    ("^[ \t]*\\_<local\\_>"
-     (0 font-lock-keyword-face)
-
-     ;; (* nonl) at the end is to consume trailing characters or otherwise they
-     ;; delimited matcher would attempt to parse them afterwards and wrongly
-     ;; highlight parentheses as incorrect variable name characters.
-     (,(lua-rx point ws lua-funcheader (* nonl))
-      nil nil
-      (1 font-lock-function-name-face nil noerror))
-
-     (,(lua-make-delimited-matcher (lua-rx lua-name) ","
-                                   (lua-rx lua-assignment-op))
-      nil nil
-      (1 font-lock-variable-name-face nil noerror)
-      (2 font-lock-warning-face t noerror)
-      (3 font-lock-warning-face t noerror)))
-
-    (,(lua-rx (or bol ";") ws lua-funcheader)
+    (,(lua-rx (symbol "for") ws+ lua-up-to-9-variables)
+     (1 font-lock-variable-name-face)
+     (2 font-lock-variable-name-face nil noerror)
+     (3 font-lock-variable-name-face nil noerror)
+     (4 font-lock-variable-name-face nil noerror)
+     (5 font-lock-variable-name-face nil noerror)
+     (6 font-lock-variable-name-face nil noerror)
+     (7 font-lock-variable-name-face nil noerror)
+     (8 font-lock-variable-name-face nil noerror)
+     (9 font-lock-variable-name-face nil noerror))
+
+    (,(lua-rx (symbol "function") (? ws+ lua-funcname) ws "(" ws 
lua-up-to-9-variables)
+     (1 font-lock-variable-name-face)
+     (2 font-lock-variable-name-face nil noerror)
+     (3 font-lock-variable-name-face nil noerror)
+     (4 font-lock-variable-name-face nil noerror)
+     (5 font-lock-variable-name-face nil noerror)
+     (6 font-lock-variable-name-face nil noerror)
+     (7 font-lock-variable-name-face nil noerror)
+     (8 font-lock-variable-name-face nil noerror)
+     (9 font-lock-variable-name-face nil noerror))
+
+    (,(lua-rx lua-funcheader)
      (1 font-lock-function-name-face))
 
+    ;; local x, y, z
+    ;; local x = .....
+    ;;
+    ;; NOTE: this is intentionally below funcheader matcher, so that in
+    ;;
+    ;; local foo = function() ...
+    ;;
+    ;; "foo" is fontified as function-name-face, and variable-name-face is not 
applied.
+    (,(lua-rx (symbol "local") ws+ lua-up-to-9-variables)
+     (1 font-lock-variable-name-face)
+     (2 font-lock-variable-name-face nil noerror)
+     (3 font-lock-variable-name-face nil noerror)
+     (4 font-lock-variable-name-face nil noerror)
+     (5 font-lock-variable-name-face nil noerror)
+     (6 font-lock-variable-name-face nil noerror)
+     (7 font-lock-variable-name-face nil noerror)
+     (8 font-lock-variable-name-face nil noerror)
+     (9 font-lock-variable-name-face nil noerror))
+
     (,(lua-rx (or (group-n 1
                            "@" (symbol "author" "copyright" "field" "release"
                                        "return" "see" "usage" "description"))
diff --git a/test/test-font-lock.el b/test/test-font-lock.el
index f30b1fc..5b9cfce 100644
--- a/test/test-font-lock.el
+++ b/test/test-font-lock.el
@@ -68,10 +68,9 @@ _table.sort(foobar)
 
     (expect "_do foo(5) end_"
             :to-be-fontified-as
-            '(nil))
-    )
+            '(nil)))
   (it "fontifies keywords used as attributes"
-     ;; Hint user that keywords cannot be used like that
+    ;; Hint user that keywords cannot be used like that
     (expect "foo(5).end"
             :to-be-fontified-as
             '(("end" keyword)))
@@ -79,20 +78,64 @@ _table.sort(foobar)
             :to-be-fontified-as
             '(("end" keyword)))))
 
+(describe "Fontification of variables"
+  (it "fontifies \"local foo, bar, baz = 1, 2, 3\""
+    (expect "local foo,bar  ,   baz = 1, 2, 3"
+            :to-be-fontified-as '(("local" keyword "foo" variable-name "bar" 
variable-name "baz" variable-name))))
+
+  (it "fontifies \"local foo, bar, baz\""
+    (expect "local foo,bar  ,   baz"
+            :to-be-fontified-as '(("local" keyword "foo" variable-name "bar" 
variable-name "baz" variable-name))))
+
+  (it "fontifies \"local x =\" at end of buffer"
+    (expect "local x ="
+            :to-be-fontified-as '(("local" keyword "x" variable-name))))
+
+  (it "fontifies local \"x =\" at end of line"
+    ;; Issue #163
+    (expect "local x =
+
+foo = bar"
+            :to-be-fontified-as '(("local" keyword "x" variable-name)
+                                  ()
+                                  ())))
+
+  (it "fontifies \"for x123 =\""
+    (expect "for x123 ="
+            :to-be-fontified-as '(("for" keyword "x123" variable-name))))
+
+  (it "fontifies \"for x, y, z\""
+    (expect "for x, y, z in "
+            :to-be-fontified-as '(("for" keyword "x" variable-name "y" 
variable-name "z" variable-name
+                                   "in" keyword)))))
+
 
 (describe "Fontification of function headers"
   (it "fontifies function <name>(...) headers"
-    (expect "function bar() end"
-            :to-be-fontified-as '(("function" keyword "bar" function-name 
"end" keyword))))
+    (expect "function bar(x, y) end"
+            :to-be-fontified-as '(("function" keyword "bar" function-name
+                                   "x" variable-name "y" variable-name
+                                   "end" keyword))))
   (it "fontifies local function <name>(...) headers"
-    (expect "local function baz() end"
-            :to-be-fontified-as '(("local" keyword "function" keyword "baz" 
function-name "end" keyword))))
+    (expect "local function baz(x, y) end"
+            :to-be-fontified-as '(("local" keyword "function" keyword "baz" 
function-name
+                                   "x" variable-name "y" variable-name
+                                   "end" keyword))))
   (it "fontifies <name> = function (...) headers"
-    (expect "qux = function() end"
-            :to-be-fontified-as '(("qux" function-name "function" keyword 
"end" keyword))))
+    (expect "qux = function(x, y) end"
+            :to-be-fontified-as '(("qux" function-name "function" keyword
+                                   "x" variable-name "y" variable-name
+                                   "end" keyword))))
   (it "fontifies local <name> = function (...) headers"
-    (expect "local quux = function() end"
-            :to-be-fontified-as '(("local" keyword "quux" function-name 
"function" keyword "end" keyword))))
+    (expect "local quux = function(x, y) end"
+            :to-be-fontified-as '(("local" keyword "quux" function-name 
"function" keyword
+                                   "x" variable-name "y" variable-name
+                                   "end" keyword))))
+
+  (it "fontifies parameters in function literals"
+    (expect "foo(function(x, y))"
+            :to-be-fontified-as '(("function" keyword
+                                   "x" variable-name "y" variable-name))))
 
   (it "fontifies different variations of headers altogether"
     (expect
@@ -147,7 +190,7 @@ end"
        ("end" keyword))))
 
   (it "does not choke on function names with underscores"
-   (expect
+    (expect
      ;; Check all defun variants, check embedded defuns
      "\
 function foo()