vim-patch:a4c085a3e607

runtime(java): Improve the recognition of the "style" method declarations

- Request the new regexp engine (v7.3.970) for [:upper:] and
  [:lower:].

- Recognise declarations of in-line annotated methods.

- Recognise declarations of _strictfp_ methods.

- Establish partial order for method modifiers as shown in
  the MethodModifier production; namely, _public_ and
  friends should be written the leftmost, possibly followed
  by _abstract_ or _default_, or possibly followed by other
  modifiers.

- Stop looking for parameterisable primitive types (void<?>,
  int<Object>, etc., are malformed).

- Stop looking for arrays of _void_.

- Acknowledge the prevailing convention for method names to
  begin with a small letter and for class/interface names to
  begin with a capital letter; and, therefore, desist from
  claiming declarations of enum constants and constructors
  with javaFuncDef.
  Rationale:
    + Constructor is distinct from method:
      * its (overloaded) name is not arbitrary;
      * its return type is implicit;
      * its _throws_ clause depends on indirect vagaries of
        instance (variable) initialisers;
      * its invocation makes other constructors of its type
        hierarchy invoked one by one, concluding with the
        primordial constructor;
      * its explicit invocation, via _this_ or _super_, can
        only appear as the first statement in a constructor
        (not anymore, see JEP 447); else, its _super_ call
        cannot appear in constructors of _record_ or _enum_;
        and neither invocation is allowed for the primordial
        constructor;
      * it is not a member of its class, like initialisers,
        and is never inherited;
      * it is never _abstract_ or _native_.
    + Constructor declarations tend to be few in number and
      merit visual recognition from method declarations.
    + Enum constants define a fixed set of type instances
      and more resemble class variable initialisers.

Note that the code duplicated for @javaFuncParams is written
keeping in mind for g:java_highlight_functions a pending 3rd
variant, which would require none of the :syn-cluster added
groups.

closes: vim/vim#14620

a4c085a3e6

Co-authored-by: Aliaksei Budavei <0x000c70@gmail.com>

runtime/syntax/java.vim

@@ -3,7 +3,7 @@
 " Maintainer:		Aliaksei Budavei <0x000c70 AT gmail DOT com>
 " Former Maintainer:	Claudio Fleiner <claudio@fleiner.com>
 " Repository:		https://github.com/zzzyxwvut/java-vim.git
-" Last Change:		2024 Apr 13
+" Last Change:		2024 Apr 22
 
 " Please check :help java.vim for comments on some of the options available.
 
@@ -82,7 +82,8 @@ syn match   javaConceptKind	"\<default\>\%(\s*\%(:\|->\)\)\@!"
 " ".java\=" extension used for a production version and an arbitrary
 " extension used for a testing version.
 let s:module_info_cur_buf = fnamemodify(bufname("%"), ":t") =~ '^module-info\%(\.class\>\)\@!'
-lockvar s:module_info_cur_buf
+let s:selectable_regexp_engine = !(v:version < 704)
+lockvar s:selectable_regexp_engine s:module_info_cur_buf
 
 " Java modules (since Java 9, for "module-info.java" file).
 if s:module_info_cur_buf
@@ -287,24 +288,29 @@ syn match   javaSpecial "\\u\x\x\x\x"
 
 syn cluster javaTop add=javaString,javaStrTempl,javaCharacter,javaNumber,javaSpecial,javaStringError,javaTextBlockError
 
+" Method declarations (JLS-17, §8.4.3, §8.4.4, §9.4).
 if exists("java_highlight_functions")
+  syn cluster javaFuncParams contains=javaAnnotation,@javaClasses,javaType,javaVarArg,javaComment,javaLineComment
+
   if java_highlight_functions == "indent"
-    syn match javaFuncDef "^\%(\t\|  \%( \{6\}\)\=\)\K\%(\k\|[ .,<>\[\]]\)*([^-+*/]*)" contains=javaScopeDecl,javaConceptKind,javaType,javaStorageClass,@javaClasses,javaAnnotation
-    syn region javaFuncDef start=+^\%(\t\|  \%( \{6\}\)\=\)\K\%(\k\|[ .,<>\[\]]\)*([^-+*/]*,\s*+ end=+)+ contains=javaScopeDecl,javaConceptKind,javaType,javaStorageClass,@javaClasses,javaAnnotation
+    syn cluster javaFuncParams add=javaScopeDecl,javaConceptKind,javaStorageClass,javaExternal
+    syn match javaFuncDef "^\%(\t\|  \%( \{6\}\)\=\)\K\%(\k\|[ .,<>\[\]]\)*([^-+*/]*)" contains=@javaFuncParams
+    syn region javaFuncDef start=+^\%(\t\|  \%( \{6\}\)\=\)\K\%(\k\|[ .,<>\[\]]\)*([^-+*/]*,\s*+ end=+)+ contains=@javaFuncParams
   else
     " This is the "style" variant (:help ft-java-syntax).
-    "
-    " Match arbitrarily indented method and constructor declarations
-    " and some enum constants.
-    "
-    " TODO: Come back to refine and fix the parts of javaFuncDef.
-    " TODO: Request the new regexp engine for [:upper:] and [:lower:].
-    "
+    syn cluster javaFuncParams add=javaScopeDecl,javaConceptKind,javaStorageClass,javaExternal
+
+    " Match arbitrarily indented camelCasedName method declarations.
+    " Match: [@ɐ] [abstract] [<α, β>] Τʬ[<γ>][[][]] μʭʭ(/* ... */);
+
+    if s:selectable_regexp_engine
+      " Request the new regexp engine for [:upper:] and [:lower:].
+      syn region javaFuncDef start=/\%#=2^\s\+\%(\%(@\%(\K\k*\.\)*\K\k*\>\)\s\+\)*\%(p\%(ublic\|rotected\|rivate\)\s\+\)\=\%(\%(abstract\|default\)\s\+\|\%(\%(final\|\%(native\|strictfp\)\|s\%(tatic\|ynchronized\)\)\s\+\)*\)\=\%(<.*[[:space:]-]\@1<!>\s\+\)\=\%(void\|\%(b\%(oolean\|yte\)\|char\|short\|int\|long\|float\|double\|\%(\<\K\k*\>\.\)*\<[$_[:upper:]]\k*\>\%(<[^(){}]*[[:space:]-]\@1<!>\)\=\)\%(\[\]\)*\)\s\+\<[$_[:lower:]]\k*\>\s*(/ end=/)/ skip=/\/\*.\{-}\*\/\|\/\/.*$/ contains=@javaFuncParams
+    else
       " XXX: \C\<[^a-z0-9]\k*\> rejects "type", but matches "τύπος".
       " XXX: \C\<[^A-Z0-9]\k*\> rejects "Method", but matches "Μέθοδος".
-    "
-    " Match: [abstract] [<α, β>] [Τʬ][<γ>][[][]] [μΜ]ʭʭ(/* ... */);
-    syn region javaFuncDef start=+^\s\+\%(\%(public\|protected\|private\|static\|\%(abstract\|default\)\|final\|native\|synchronized\)\s\+\)*\%(<.*>\s\+\)\=\%(\%(void\|boolean\|char\|byte\|short\|int\|long\|float\|double\|\%(\K\k*\.\)*\<[^a-z0-9]\k*\>\)\%(<[^(){}]*>\)\=\%(\[\]\)*\s\+\<[^A-Z0-9]\k*\>\|\<[^a-z0-9]\k*\>\)\s*(+ end=+)+ contains=javaScopeDecl,javaConceptKind,javaType,javaStorageClass,javaComment,javaLineComment,@javaClasses,javaAnnotation
+      syn region javaFuncDef start=/^\s\+\%(\%(@\%(\K\k*\.\)*\K\k*\>\)\s\+\)*\%(p\%(ublic\|rotected\|rivate\)\s\+\)\=\%(\%(abstract\|default\)\s\+\|\%(\%(final\|\%(native\|strictfp\)\|s\%(tatic\|ynchronized\)\)\s\+\)*\)\=\%(<.*[[:space:]-]\@1<!>\s\+\)\=\%(void\|\%(b\%(oolean\|yte\)\|char\|short\|int\|long\|float\|double\|\%(\<\K\k*\>\.\)*\<[^a-z0-9]\k*\>\%(<[^(){}]*[[:space:]-]\@1<!>\)\=\)\%(\[\]\)*\)\s\+\<[^A-Z0-9]\k*\>\s*(/ end=/)/ skip=/\/\*.\{-}\*\/\|\/\/.*$/ contains=@javaFuncParams
+    endif
   endif
 
   syn match   javaLambdaDef "\<\K\k*\>\%(\<default\>\)\@<!\s*->"
@@ -476,6 +482,6 @@ endif
 
 let b:spell_options = "contained"
 let &cpo = s:cpo_save
-unlet s:module_info_cur_buf s:cpo_save
+unlet s:selectable_regexp_engine s:module_info_cur_buf s:cpo_save
 
 " vim: ts=8