#!/bin/sh
#-*-mode:sh;indent-tabs-mode:nil;tab-width:2;coding:utf-8-*-┐
#───vi: set net ft=sh ts=2 sts=2 fenc=utf-8 :vi─────────────┘
#
# OVERVIEW
#
#   Header Symbol Index Generator
#
# DESCRIPTION
#
#   This is a static source analyzer that lets us configure Emacs
#   keybindings to insert #include lines.
#
# EXAMPLES
#
#   build/htags -o HTAGS $(find . -name \*.h)
#
#   (defun jart-add-include ()
#     (interactive)
#     (let* ((tag-file "HTAGS")
#            (case-fold-search nil)
#            (search (thing-at-point 'symbol))
#            (buffer (find-file-noselect (format "%s/%s"
#                                                (locate-dominating-file
#                                                 (buffer-name) tag-file)
#                                                tag-file)))
#            (header (with-current-buffer buffer
#                      (save-excursion
#                        (goto-char 0)
#                        (when (re-search-forward
#                               (concat "\177" search "\001") nil t)
#                          (when (re-search-backward "\f\n\\([^,]*\\)," nil t)
#                            (match-string 1)))))))
#       (when header
#         (save-excursion
#           (goto-char 0)
#           (re-search-forward "#include")
#           (re-search-forward "^$")
#           (insert (concat "#include \"" header "\"\n"))))))
#   (defun jart-c-mode-common-hook ()
#     (define-key c-mode-base-map (kbd "C-c C-h") 'jart-add-include))
#   (eval-after-load 'markdown-mode
#     '(progn
#        (add-hook 'c-mode-common-hook 'jart-c-mode-common-hook)))

# ctags doesn't understand variable prototypes, e.g.
#   extern char **environ;
set -- --regex-c='/^\(\(hidden\|extern\|const\) \)*[_[:alpha:]][_[:alnum:]]*[ *][ *]*\([_[:alpha:]][_[:alnum:]]*[ *][ *]*\)*\([_[:alpha:]][_$[:alnum:]]*\)/\4/b' "$@"

# ctags doesn't understand function prototypes, e.g.
#   bool isheap(void *p) nothrow nocallback;
set -- --regex-c='/^[_[:alpha:]][_[:alnum:]]*[ *][ *]*\([_[:alpha:]][_[:alnum:]]*[ *][ *]*\)*\([_[:alpha:]][_$[:alnum:]]*\)(.*/\2/b' "$@"

# ctags doesn't understand function pointers, e.g.
#   extern int32_t (*const SetEvent)(int64_t hEvent) wincall;
set -- --regex-c='/^extern [^(]*(\*const \([^)]*\))(/\1/b' "$@"

# ctags doesn't understand forward declarations, e.g.
#   struct WorstSoftwareEver;
set -- --regex-c='/^struct.*;$/uehocruehcroue/b' "$@"

exec ${TAGS:-ctags}                                               \
     -e                                                           \
     --langmap=c:.c.h                                             \
     --exclude=libc/nt/struct/imagefileheader.internal.h          \
     --exclude=libc/nt/struct/imageseparatedebugheader.internal.h \
     --exclude=libc/nt/struct/importobjectheader.h                \
     --exclude=libc/nt/struct/nonpageddebuginfo.h                 \
     --exclude=libc/nt/struct/ansistring.h                        \
     --exclude=libc/nt/struct/filesegmentelement.h                \
     "$@"