runtime(filetype): improve *.h filetype detection
This commit changes *.h files to default to C (instead of C++), and
deprecates the existing `g:c_syntax_for_h` and `g:ch_syntax_for_h`
variables in favor of a unified `g:filetype_h`, like is used for other
ambiguous file extensions.
closes: #17135
Signed-off-by: Amelia Clarke <selene@perilune.dev>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/autoload/dist/ft.vim b/runtime/autoload/dist/ft.vim
index a0be930..0c0b872 100644
--- a/runtime/autoload/dist/ft.vim
+++ b/runtime/autoload/dist/ft.vim
@@ -3,7 +3,7 @@
# Vim functions for file type detection
#
# Maintainer: The Vim Project <https://github.com/vim/vim>
-# Last Change: 2025 Apr 15
+# Last Change: 2025 Apr 19
# Former Maintainer: Bram Moolenaar <Bram@vim.org>
# These functions are moved here from runtime/filetype.vim to make startup
@@ -203,19 +203,36 @@
setf c
enddef
-export def FTheader()
- if match(getline(1, min([line("$"), 200])), '^@\(interface\|end\|class\)') > -1
- if exists("g:c_syntax_for_h")
- setf objc
- else
- setf objcpp
+# Searches within the first `maxlines` lines of the file for distinctive
+# Objective-C or C++ syntax and returns the appropriate filetype. Returns a
+# null_string if the search was inconclusive.
+def CheckObjCOrCpp(maxlines = 100): string
+ var n = 1
+ while n < maxlines && n <= line('$')
+ const line = getline(n)
+ if line =~ '\v^\s*\@%(class|interface|end)>'
+ return 'objcpp'
+ elseif line =~ '\v^\s*%(class|namespace|template|using)>'
+ return 'cpp'
endif
- elseif exists("g:c_syntax_for_h")
+ ++n
+ endwhile
+ return null_string
+enddef
+
+# Determines whether a *.h file is C, C++, Ch, or Objective-C/Objective-C++.
+export def FTheader()
+ if exists('g:filetype_h')
+ execute $'setf {g:filetype_h}'
+ elseif exists('g:c_syntax_for_h')
setf c
- elseif exists("g:ch_syntax_for_h")
+ elseif exists('g:ch_syntax_for_h')
setf ch
else
- setf cpp
+ # Search the first 100 lines of the file for distinctive Objective-C or C++
+ # syntax and set the filetype accordingly. Otherwise, use C as the default
+ # filetype.
+ execute $'setf {CheckObjCOrCpp() ?? 'c'}'
endif
enddef
diff --git a/runtime/doc/filetype.txt b/runtime/doc/filetype.txt
index c0bf1e6..77bf5f3 100644
--- a/runtime/doc/filetype.txt
+++ b/runtime/doc/filetype.txt
@@ -1,4 +1,4 @@
-*filetype.txt* For Vim version 9.1. Last change: 2025 Apr 16
+*filetype.txt* For Vim version 9.1. Last change: 2025 Apr 19
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -153,7 +153,11 @@
*.f g:filetype_f |ft-forth-syntax|
*.frm g:filetype_frm |ft-form-syntax|
*.fs g:filetype_fs |ft-forth-syntax|
- *.h g:c_syntax_for_h |ft-c-syntax|
+ *.h g:c_syntax_for_h |ft-c-syntax| (deprecated)
+ *.h g:ch_syntax_for_h |ft-ch-syntax| (deprecated)
+ *.h g:filetype_h |ft-c-syntax|
+ |ft-ch-syntax|
+ |ft-cpp-syntax|
*.i g:filetype_i |ft-progress-syntax|
*.inc g:filetype_inc
*.lsl g:filetype_lsl
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index ae89bd9..a8fbe1a 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt* For Vim version 9.1. Last change: 2025 Apr 15
+*syntax.txt* For Vim version 9.1. Last change: 2025 Apr 19
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -1056,8 +1056,12 @@
*c_ansi_typedefs* ... but do standard ANSI types
*c_ansi_constants* ... but do standard ANSI constants
*c_no_utf* don't highlight \u and \U in strings
-*c_syntax_for_h* for *.h files use C syntax instead of C++ and use objc
- syntax instead of objcpp
+*c_syntax_for_h* use C syntax for *.h files instead of C++/ObjC/ObjC++
+ (NOTE: This variable is deprecated and no longer
+ necessary, as *.h files now default to C, unless the
+ file contains C++ or Objective-C syntax. If the
+ automated detection fails, the default filetype can
+ be adjusted using `g:filetype_h`.)
*c_no_if0* don't highlight "#if 0" blocks as comments
*c_no_cformat* don't highlight %-formats in strings
*c_no_c99* don't highlight C99 standard items
@@ -1116,8 +1120,11 @@
By setting a variable you can tell Vim to use Ch syntax for *.h files, instead
of C or C++: >
- :let ch_syntax_for_h = 1
+ :let g:filetype_h = 'ch'
+NOTE: In previous versions of Vim, the following (now-deprecated) variable was
+used, but is no longer the preferred approach: >
+ :let ch_syntax_for_h = 1
CHILL *chill.vim* *ft-chill-syntax*
diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index e850074..da74e25 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -1,7 +1,7 @@
" Vim support file to detect file types
"
" Maintainer: The Vim Project <https://github.com/vim/vim>
-" Last Change: 2025 Apr 18
+" Last Change: 2025 Apr 19
" Former Maintainer: Bram Moolenaar <Bram@vim.org>
" Listen very carefully, I will say this only once
@@ -436,9 +436,8 @@
" https://clang.llvm.org/docs/StandardCPlusPlusModules.html#file-name-requirement
au BufNewFile,BufRead *.cppm,*.ccm,*.cxxm,*.c++m setf cpp
-" .h files can be C, Ch C++, ObjC or ObjC++.
-" Set c_syntax_for_h if you want C, ch_syntax_for_h if you want Ch. ObjC is
-" detected automatically.
+" .h files can be C, C++, Ch, Objective-C, or Objective-C++.
+" Set g_filetype_h to set a different filetype
au BufNewFile,BufRead *.h call dist#ft#FTheader()
" Ch (CHscript)