Subject: bug#46055: [PATCH] Add rust lang to etags

From: Pierre-Antoine Rouby <[email-masked]>
Date: Mon, 25 Jan 2021 11:15:46 +0100

* lib-src/etags.c (Rust_functions): New function to make tags for rust
files.
  (Rust_help, Rust_suffixes): New constant.
* doc/emacs/maintaining.texi (Tag Syntax): Add Rust item.
* doc/man/etags.1: Add Rust.
---
 doc/emacs/maintaining.texi |  4 ++++
 doc/man/etags.1            |  2 +-
 lib-src/etags.c            | 49 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 415815473e..0f96dc65d1 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -2639,6 +2639,10 @@ Tag Syntax
 @item
 In Ruby code, @code{def} or @code{class} or @code{module} at the
 beginning of a line generate a tag.  Constants also generate tags.
+
+@item
+In Rust code, tags anything defined with @code{fn}, @code{enum},
+@code{struct} or @code{macro_rules!}.
 @end itemize
 
   You can also generate tags based on regexp matching (@pxref{Etags
diff --git a/doc/man/etags.1 b/doc/man/etags.1
index c5c15fb182..354f6ca88b 100644
--- a/doc/man/etags.1
+++ b/doc/man/etags.1
@@ -51,7 +51,7 @@ format understood by
 \&.  Both forms of the program understand
 the syntax of C, Objective C, C++, Java, Fortran, Ada, Cobol, Erlang,
 Forth, Go, HTML, LaTeX, Emacs Lisp/Common Lisp, Lua, Makefile, Pascal, Perl,
-Ruby, PHP, PostScript, Python, Prolog, Scheme and
+Ruby, Rust, PHP, PostScript, Python, Prolog, Scheme and
 most assembler\-like syntaxes.
 Both forms read the files specified on the command line, and write a tag
 table (defaults: \fBTAGS\fP for \fBetags\fP, \fBtags\fP for
diff --git a/lib-src/etags.c b/lib-src/etags.c
index b5c18e0e01..8243861c69 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -366,6 +366,7 @@ #define xrnew(op, n, m) ((op) = xnrealloc (op, n, (m) * sizeof *(op)))
 static void Prolog_functions (FILE *);
 static void Python_functions (FILE *);
 static void Ruby_functions (FILE *);
+static void Rust_functions (FILE *);
 static void Scheme_functions (FILE *);
 static void TeX_commands (FILE *);
 static void Texinfo_nodes (FILE *);
@@ -752,6 +753,12 @@ #define STDIN 0x1001		/* returned by getopt_long on --parse-stdin */
 static const char *Ruby_interpreters [] =
   { "ruby", NULL };
 
+static const char *Rust_suffixes [] =
+  { "rs", NULL };
+static const char Rust_help [] =
+  "In Rust code, tags anything defined with 'fn', 'enum', \n\
+'struct' or 'macro_rules!'.";
+
 /* Can't do the `SCM' or `scm' prefix with a version number. */
 static const char *Scheme_suffixes [] =
   { "oak", "sch", "scheme", "SCM", "scm", "SM", "sm", "ss", "t", NULL };
@@ -836,6 +843,7 @@ #define STDIN 0x1001		/* returned by getopt_long on --parse-stdin */
                  NULL,           Python_interpreters },
   { "ruby",      Ruby_help,      Ruby_functions,    Ruby_suffixes,
                  Ruby_filenames, Ruby_interpreters },
+  { "rust",      Rust_help,      Rust_functions,    Rust_suffixes      },
   { "scheme",    Scheme_help,    Scheme_functions,  Scheme_suffixes    },
   { "tex",       TeX_help,       TeX_commands,      TeX_suffixes       },
   { "texinfo",   Texinfo_help,   Texinfo_nodes,     Texinfo_suffixes   },
@@ -5019,6 +5027,47 @@ Ruby_functions (FILE *inf)
     }
 }
 
+
+/*
+ * Rust support
+ * Look for:
+ *  - fn: Function
+ *  - struct: Structure
+ *  - enum: Enumeration
+ *  - macro_rules!: Macro
+ */
+static void
+Rust_functions (FILE *inf)
+{
+  char *cp, *name;
+
+  LOOP_ON_INPUT_LINES(inf, lb, cp)
+    {
+      cp = skip_spaces(cp);
+      name = cp;
+
+      // Skip 'pub' keyworld
+      (void)LOOKING_AT (cp, "pub");
+
+      // Look for define
+      if (LOOKING_AT (cp, "fn")
+	  || LOOKING_AT (cp, "enum")
+	  || LOOKING_AT (cp, "struct")
+	  || LOOKING_AT (cp, "macro_rules!"))
+	{
+	  cp = skip_spaces (cp);
+	  name = cp;
+
+	  while (!notinname (*cp))
+	    cp++;
+
+	  make_tag (name, cp - name, true,
+		    lb.buffer, cp - lb.buffer + 1,
+		    lineno, linecharno);
+	}
+    }
+}
+
 
 /*
  * PHP support
-- 
2.29.2