Support Go language in 'etags'

* lib-src/etags.c <Ruby_help>: Fix documentation of Ruby tags.
<Go_help>: New help.
<Go_suffixes>: New variable.
(Go_functions): New function.
<lang_names>: Add entry for Go.  (Bug#22370)

* doc/emacs/maintaining.texi (Tag Syntax): Document Go support.
* doc/man/etags.1: Mention Go support.

* etc/NEWS: Mention Go support.

* test/etags/go-src/test.go:
* test/etags/go-src/test1.go: New test files.
* test/etags/Makefile (GOSRC): New variable.
(SRCS): Add $(GOSRC).
* test/etags/ETAGS.good_1:
* test/etags/ETAGS.good_2:
* test/etags/ETAGS.good_3:
* test/etags/ETAGS.good_4:
* test/etags/ETAGS.good_5:
* test/etags/ETAGS.good_6:
* test/etags/CTAGS.good: Adapt to addition of Go tests.

14 files changed, 223 insertions, 5 deletions

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 7039de63e5..3f1a9c07e9 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -2218,6 +2218,9 @@ in the file.
 In Fortran code, functions, subroutines and block data are tags.
 
 @item
+In Go code, packages, functions, and types are tags.
+
+@item
 In HTML input files, the tags are the @code{title} and the @code{h1},
 @code{h2}, @code{h3} headers.  Also, tags are @code{name=} in anchors
 and all occurrences of @code{id=}.
diff --git a/doc/man/etags.1 b/doc/man/etags.1
index d34063f23c..fc247f758a 100644
--- a/doc/man/etags.1
+++ b/doc/man/etags.1
@@ -50,7 +50,7 @@ format understood by
 .BR vi ( 1 )\c
 \&.  Both forms of the program understand
 the syntax of C, Objective C, C++, Java, Fortran, Ada, Cobol, Erlang,
-Forth, HTML, LaTeX, Emacs Lisp/Common Lisp, Lua, Makefile, Pascal, Perl,
+Forth, Go, HTML, LaTeX, Emacs Lisp/Common Lisp, Lua, Makefile, Pascal, Perl,
 Ruby, PHP, PostScript, Python, Prolog, Scheme and
 most assembler\-like syntaxes.
 Both forms read the files specified on the command line, and write a tag
diff --git a/etc/NEWS b/etc/NEWS
index 78dce166b4..d0415a22f9 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1834,6 +1834,10 @@ Names of modules, classes, methods, functions, and constants are
 tagged.  Overloaded operators are also tagged.
 
 +++
+*** New language Go
+Names of packages, functions, and types are tagged.
+
++++
 *** Improved support for Lua
 
 Etags now tags functions even if the "function" keyword follows some
diff --git a/lib-src/etags.c b/lib-src/etags.c
index adc08a2367..bdfced5bc9 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -354,6 +354,7 @@ static void Cstar_entries (FILE *);
 static void Erlang_functions (FILE *);
 static void Forth_words (FILE *);
 static void Fortran_functions (FILE *);
+static void Go_functions (FILE *);
 static void HTML_labels (FILE *);
 static void Lisp_functions (FILE *);
 static void Lua_functions (FILE *);
@@ -641,6 +642,10 @@ static const char *Fortran_suffixes [] =
 static const char Fortran_help [] =
 "In Fortran code, functions, subroutines and block data are tags.";
 
+static const char *Go_suffixes [] = {"go", NULL};
+static const char Go_help [] =
+  "In Go code, functions, interfaces and packages are tags.";
+
 static const char *HTML_suffixes [] =
   { "htm", "html", "shtml", NULL };
 static const char HTML_help [] =
@@ -727,7 +732,7 @@ static const char *Ruby_suffixes [] =
   { "rb", "ruby", NULL };
 static const char Ruby_help [] =
   "In Ruby code, 'def' or 'class' or 'module' at the beginning of\n\
-a line generate a tag.";
+a line generate a tag.  Constants also generate a tag.";
 
 /* Can't do the `SCM' or `scm' prefix with a version number. */
 static const char *Scheme_suffixes [] =
@@ -794,6 +799,7 @@ static language lang_names [] =
   { "erlang",    Erlang_help,    Erlang_functions,  Erlang_suffixes    },
   { "forth",     Forth_help,     Forth_words,       Forth_suffixes     },
   { "fortran",   Fortran_help,   Fortran_functions, Fortran_suffixes   },
+  { "go",        Go_help,        Go_functions,      Go_suffixes        },
   { "html",      HTML_help,      HTML_labels,       HTML_suffixes      },
   { "java",      Cjava_help,     Cjava_entries,     Cjava_suffixes     },
   { "lisp",      Lisp_help,      Lisp_functions,    Lisp_suffixes      },
@@ -4209,6 +4215,73 @@ Fortran_functions (FILE *inf)
 
 
 /*
+ * Go language support
+ * Original code by Xi Lu <lx@shellcodes.org> (2016)
+ */
+static void
+Go_functions(FILE *inf)
+{
+  char *cp, *name;
+
+  LOOP_ON_INPUT_LINES(inf, lb, cp)
+    {
+      cp = skip_spaces (cp);
+
+      if (LOOKING_AT (cp, "package"))
+	{
+	  name = cp;
+	  while (!notinname (*cp) && *cp != '\0')
+	    cp++;
+	  make_tag (name, cp - name, false, lb.buffer,
+		    cp - lb.buffer + 1, lineno, linecharno);
+	}
+      else if (LOOKING_AT (cp, "func"))
+	{
+	  /* Go implementation of interface, such as:
+	     func (n *Integer) Add(m Integer) ...
+	     skip `(n *Integer)` part.
+	  */
+	  if (*cp == '(')
+	    {
+	      while (*cp != ')')
+		cp++;
+	      cp = skip_spaces (cp+1);
+	    }
+
+	  if (*cp)
+	    {
+	      name = cp;
+
+	      while (!notinname (*cp))
+		cp++;
+
+	      make_tag (name, cp - name, true, lb.buffer,
+			cp - lb.buffer + 1, lineno, linecharno);
+	    }
+	}
+      else if (members && LOOKING_AT (cp, "type"))
+	{
+	  name = cp;
+
+	  /* Ignore the likes of the following:
+	     type (
+	            A
+	     )
+	   */
+	  if (*cp == '(')
+	    return;
+
+	  while (!notinname (*cp) && *cp != '\0')
+	    cp++;
+
+	  make_tag (name, cp - name, false, lb.buffer,
+		    cp - lb.buffer + 1, lineno, linecharno);
+	}
+    }
+}
+
+
+/*
  * Ada parsing
  * Original code by
  * Philippe Waroquiers (1998)
diff --git a/test/etags/CTAGS.good b/test/etags/CTAGS.good
index 86eb9f85cf..846725ef71 100644
--- a/test/etags/CTAGS.good
+++ b/test/etags/CTAGS.good
@@ -947,6 +947,10 @@ MoveLayerAfter	lua-src/allegro.lua	/^function MoveLayerAfter (this_one)$/
 MoveLayerBefore	lua-src/allegro.lua	/^function MoveLayerBefore (this_one)$/
 MoveLayerBottom	lua-src/allegro.lua	/^function MoveLayerBottom ()$/
 MoveLayerTop	lua-src/allegro.lua	/^function MoveLayerTop ()$/
+Mtest.go	go-src/test.go	1
+Mtest.go	go-src/test.go	/^func main() {$/
+Mtest1.go	go-src/test1.go	1
+Mtest1.go	go-src/test1.go	/^func main() {$/
 Mx.cc	cp-src/x.cc	/^main(int argc, char *argv[])$/
 NAME	y-src/cccp.c	8
 NATNUMP	c-src/emacs/src/lisp.h	/^NATNUMP (Lisp_Object x)$/
@@ -1077,6 +1081,8 @@ Pkg1_Proc2/p	ada-src/waroquiers.ada	/^  procedure Pkg1_Proc2 (I : Integer);$/
 Pkg1_Proc2/p	ada-src/waroquiers.ada	/^  procedure Pkg1_Proc2 (I : Integer) is$/
 PostControls	pyt-src/server.py	/^    def PostControls(self):$/
 Pre_Call_State/t	ada-src/2ataspri.ads	/^   type Pre_Call_State is new System.Address;$/
+PrintAdd	go-src/test1.go	/^func (s str) PrintAdd() {$/
+PrintAdd	go-src/test1.go	/^func (n intNumber) PrintAdd() {$/
 Private	objc-src/Subprocess.m	/^@interface Subprocess(Private)$/
 Private_T/b	ada-src/etags-test-for.ada	/^    task body Private_T is$/
 Private_T/b	ada-src/waroquiers.ada	/^    task body Private_T is$/
@@ -3135,6 +3141,7 @@ instance_method_question?	ruby-src/test.rb	/^        def instance_method_questio
 instr	y-src/parse.y	80
 instr	parse.y	80
 instruct	c-src/etags.c	2527
+intNumber	go-src/test1.go	13
 integer	c-src/emacs/src/lisp.h	2127
 integer	cccp.y	113
 integer	y-src/cccp.y	112
@@ -3738,6 +3745,7 @@ plain_C_suffixes	c-src/etags.c	643
 plainc	c-src/etags.c	2934
 plist	c-src/emacs/src/lisp.h	697
 plus	cp-src/functions.cpp	/^void Date::plus ( int days , int month , int year /
+plus	go-src/test1.go	5
 plusvalseq	prol-src/natded.prolog	/^plusvalseq([]) --> [].$/
 pointer	c-src/emacs/src/lisp.h	2125
 poll_for_input	c-src/emacs/src/keyboard.c	/^poll_for_input (struct atimer *timer)$/
@@ -3950,6 +3958,7 @@ save_getcjmp	c-src/emacs/src/keyboard.c	/^save_getcjmp (sys_jmp_buf temp)$/
 save_type	c-src/emacs/src/lisp.h	/^save_type (struct Lisp_Save_Value *v, int n)$/
 savenstr	c-src/etags.c	/^savenstr (const char *cp, int len)$/
 savestr	c-src/etags.c	/^savestr (const char *cp)$/
+say	go-src/test.go	/^func say(msg string) {$/
 scan_separators	c-src/etags.c	/^scan_separators (char *name)$/
 scolonseen	c-src/etags.c	2447
 scratch	c-src/sysdep.h	56
@@ -4075,6 +4084,7 @@ step	cp-src/clheir.hpp	/^    virtual void step(void) { }$/
 step_everybody	cp-src/clheir.cpp	/^void step_everybody(void)$/
 stop_polling	c-src/emacs/src/keyboard.c	/^stop_polling (void)$/
 store_user_signal_events	c-src/emacs/src/keyboard.c	/^store_user_signal_events (void)$/
+str	go-src/test1.go	9
 strcaseeq	c-src/etags.c	/^#define strcaseeq(s,t)	(assert ((s)!=NULL && (t)!=/
 streq	c-src/etags.c	/^#define streq(s,t)	(assert ((s)!=NULL || (t)!=NULL/
 string_intervals	c-src/emacs/src/lisp.h	/^string_intervals (Lisp_Object s)$/
@@ -4217,6 +4227,7 @@ terminateInput	objc-src/Subprocess.m	/^- terminateInput$/
 test	c-src/emacs/src/lisp.h	1871
 test	cp-src/c.C	86
 test	erl-src/gs_dialog.erl	/^test() ->$/
+test	go-src/test1.go	/^func test(p plus) {$/
 test	php-src/ptest.php	/^test $/
 test.me22b	lua-src/test.lua	/^   local function test.me22b (one)$/
 test.me_22a	lua-src/test.lua	/^   function test.me_22a(one, two)$/
diff --git a/test/etags/ETAGS.good_1 b/test/etags/ETAGS.good_1
index 44ac091066..c7b122111c 100644
--- a/test/etags/ETAGS.good_1
+++ b/test/etags/ETAGS.good_1
@@ -2283,6 +2283,18 @@ constant (a-forth-constant(a-forth-constant
38,628
 code assemby-code-word 43,685
 : a-forth-word 50,870
 
+go-src/test.go,48
+package main1,0
+func say(5,28
+func main(9,72
+
+go-src/test1.go,119
+package main1,0
+func (s str) PrintAdd(17,136
+func (n intNumber) PrintAdd(21,189
+func test(25,248
+func main(29,285
+
 html-src/softwarelibero.html,200
 Cos'è il software libero?4,38
 Licenze d'uso di un programmalicenze
65,2500
diff --git a/test/etags/ETAGS.good_2 b/test/etags/ETAGS.good_2
index 8a93e3b065..8d0f33824a 100644
--- a/test/etags/ETAGS.good_2
+++ b/test/etags/ETAGS.good_2
@@ -2852,6 +2852,18 @@ constant (a-forth-constant(a-forth-constant
38,628
 code assemby-code-word 43,685
 : a-forth-word 50,870
 
+go-src/test.go,48
+package main1,0
+func say(5,28
+func main(9,72
+
+go-src/test1.go,119
+package main1,0
+func (s str) PrintAdd(17,136
+func (n intNumber) PrintAdd(21,189
+func test(25,248
+func main(29,285
+
 html-src/softwarelibero.html,200
 Cos'è il software libero?4,38
 Licenze d'uso di un programmalicenze
65,2500
diff --git a/test/etags/ETAGS.good_3 b/test/etags/ETAGS.good_3
index e575b40ab0..060389c623 100644
--- a/test/etags/ETAGS.good_3
+++ b/test/etags/ETAGS.good_3
@@ -2600,6 +2600,21 @@ constant (a-forth-constant(a-forth-constant
38,628
 code assemby-code-word 43,685
 : a-forth-word 50,870
 
+go-src/test.go,48
+package main1,0
+func say(5,28
+func main(9,72
+
+go-src/test1.go,172
+package main1,0
+type plus 5,28
+type str 9,65
+type intNumber 13,99
+func (s str) PrintAdd(17,136
+func (n intNumber) PrintAdd(21,189
+func test(25,248
+func main(29,285
+
 html-src/softwarelibero.html,200
 Cos'è il software libero?4,38
 Licenze d'uso di un programmalicenze
65,2500
diff --git a/test/etags/ETAGS.good_4 b/test/etags/ETAGS.good_4
index 2825806051..40404f9fc6 100644
--- a/test/etags/ETAGS.good_4
+++ b/test/etags/ETAGS.good_4
@@ -2447,6 +2447,18 @@ constant (a-forth-constant(a-forth-constant
38,628
 code assemby-code-word 43,685
 : a-forth-word 50,870
 
+go-src/test.go,48
+package main1,0
+func say(5,28
+func main(9,72
+
+go-src/test1.go,119
+package main1,0
+func (s str) PrintAdd(17,136
+func (n intNumber) PrintAdd(21,189
+func test(25,248
+func main(29,285
+
 html-src/softwarelibero.html,200
 Cos'è il software libero?4,38
 Licenze d'uso di un programmalicenze
65,2500
diff --git a/test/etags/ETAGS.good_5 b/test/etags/ETAGS.good_5
index 35bb353c76..432819d3b3 100644
--- a/test/etags/ETAGS.good_5
+++ b/test/etags/ETAGS.good_5
@@ -3333,6 +3333,21 @@ constant (a-forth-constant(a-forth-constant
38,628
 code assemby-code-word 43,685
 : a-forth-word 50,870
 
+go-src/test.go,48
+package main1,0
+func say(5,28
+func main(9,72
+
+go-src/test1.go,172
+package main1,0
+type plus 5,28
+type str 9,65
+type intNumber 13,99
+func (s str) PrintAdd(17,136
+func (n intNumber) PrintAdd(21,189
+func test(25,248
+func main(29,285
+
 html-src/softwarelibero.html,200
 Cos'è il software libero?4,38
 Licenze d'uso di un programmalicenze
65,2500
diff --git a/test/etags/ETAGS.good_6 b/test/etags/ETAGS.good_6
index 8add300784..4ad5d76db2 100644
--- a/test/etags/ETAGS.good_6
+++ b/test/etags/ETAGS.good_6
@@ -3333,6 +3333,21 @@ constant (a-forth-constant(a-forth-constant
38,628
 code assemby-code-word 43,685
 : a-forth-word 50,870
 
+go-src/test.go,48
+package main1,0
+func say(5,28
+func main(9,72
+
+go-src/test1.go,172
+package main1,0
+type plus 5,28
+type str 9,65
+type intNumber 13,99
+func (s str) PrintAdd(17,136
+func (n intNumber) PrintAdd(21,189
+func test(25,248
+func main(29,285
+
 html-src/softwarelibero.html,200
 Cos'è il software libero?4,38
 Licenze d'uso di un programmalicenze
65,2500
diff --git a/test/etags/Makefile b/test/etags/Makefile
index 00d5b9f52b..21a77eb0c5 100644
--- a/test/etags/Makefile
+++ b/test/etags/Makefile
@@ -11,6 +11,7 @@ ELSRC=$(addprefix ./el-src/,TAGTEST.EL emacs/lisp/progmodes/etags.el)
 ERLSRC=$(addprefix ./erl-src/,gs_dialog.erl)
 FORTHSRC=$(addprefix ./forth-src/,test-forth.fth)
 FSRC=$(addprefix ./f-src/,entry.for entry.strange_suffix entry.strange)
+GOSRC=$(addprefix ./go-src/,test.go test1.go)
 HTMLSRC=$(addprefix ./html-src/,softwarelibero.html index.shtml algrthms.html software.html)
 #JAVASRC=$(addprefix ./java-src/, )
 LUASRC=$(addprefix ./lua-src/,allegro.lua test.lua)
@@ -27,9 +28,9 @@ RBSRC=$(addprefix ./ruby-src/,test.rb test1.ruby)
 TEXSRC=$(addprefix ./tex-src/,testenv.tex gzip.texi texinfo.tex nonewline.tex)
 YSRC=$(addprefix ./y-src/,parse.y parse.c atest.y cccp.c cccp.y)
 SRCS=${ADASRC} ${ASRC} ${CSRC} ${CPSRC} ${ELSRC} ${ERLSRC} ${FSRC}\
-     ${FORTHSRC} ${HTMLSRC} ${JAVASRC} ${LUASRC} ${MAKESRC} ${OBJCSRC}\
-     ${OBJCPPSRC} ${PASSRC} ${PHPSRC} ${PERLSRC} ${PSSRC} ${PROLSRC} ${PYTSRC}\
-     ${RBSRC} ${TEXSRC} ${YSRC}
+     ${FORTHSRC} ${GOSRC} ${HTMLSRC} ${JAVASRC} ${LUASRC} ${MAKESRC}\
+     ${OBJCSRC} ${OBJCPPSRC} ${PASSRC} ${PHPSRC} ${PERLSRC} ${PSSRC}\
+     ${PROLSRC} ${PYTSRC} ${RBSRC} ${TEXSRC} ${YSRC}
 NONSRCS=./f-src/entry.strange ./erl-src/lists.erl ./cp-src/clheir.hpp.gz
 
 ETAGS_PROG=../../lib-src/etags
diff --git a/test/etags/go-src/test.go b/test/etags/go-src/test.go
new file mode 100644
index 0000000000..6aea26ef21
--- /dev/null
+++ b/test/etags/go-src/test.go
@@ -0,0 +1,11 @@
+package main
+
+import "fmt"
+
+func say(msg string) {
+	fmt.Println(msg)
+}
+
+func main() {
+	say("Hello, Emacs!")
+}
diff --git a/test/etags/go-src/test1.go b/test/etags/go-src/test1.go
new file mode 100644
index 0000000000..6d1efaaa8a
--- /dev/null
+++ b/test/etags/go-src/test1.go
@@ -0,0 +1,34 @@
+package main
+
+import "fmt"
+
+type plus interface {
+	PrintAdd()
+}
+
+type str struct {
+	a, b string
+}
+
+type intNumber struct {
+	a, b int
+}
+
+func (s str) PrintAdd() {
+	fmt.Println(s.a + s.b)
+}
+
+func (n intNumber) PrintAdd() {
+	fmt.Println(n.a + n.b)
+}
+
+func test(p plus) {
+	p.PrintAdd()
+}
+
+func main() {
+	s := str{a: "Hello,", b: "Emacs!"}
+	number := intNumber{a: 1, b: 2}
+	test(number)
+	test(s)
+}