OTAGS(1)							   User Manuals 							  OTAGS(1)

NAME

       otags - generate tags files for emacs and vi/vim from OCaml sources

SYNOPSIS

       otags [STATIC-OPTION] ... [FILE] ... [DYNAMIC-OPTION] ... [FILE] ...

DESCRIPTION

       otags  generates  TAGS  files  for emacs and tags files for vi/vim to give these editors the ability to directly jump to function and value
       definitions (use M-.  in Emacs and ^] in vi[m] with the cursor on the symbol).

       otags uses camlp4 for parsing. This is more precise than regular expression based tagging. On the downside, otags can  only  tag  syntacti-
       cally  correct  files. Furthermore, otags is OCaml version specific: Sources to be compiled with OCaml version X.Y can, in general, only be
       tagged with otags version X.Y.

       otags can tag all files that camlp4 can parse. Internally otags keeps a current parser list that can  be  modified  with  the  options  -pc
       (clear  list),  -pa  (add to list), and -pr (reset to default).	The default value of the current parser list corresponds to standard OCaml
       syntax (containing the parsers r and o, see STANDARD CAMLP4 PARSING EXTENSIONS below).  Each source file is parsed  with  a  camlp4  parser
       into  which  all parsing extensions from the current parser list have been loaded. The camlp4 standard parsers are linked into otags and if
       the current parser list contains only such parsers then the parsing module is build internally. Otherwise an  external  camlp4  process	is
       started.

       otags  tags  all  toplevel  items  in  structures and signatures, including infix operators and nested modules and signatures. It also tags
       instance variables and methods in classes and class-types.  Filenames FILE on the command line are parsed as interfaces if they have a .mli
       suffix and as implementations if they have a .ml suffix. (See also the dynamic options -intf and -impl.)

       otags can tag all files in a directory tree (if option -r is given). Files that are generated by ocamllex or ocamlyacc or that require pre-
       processing with the camlp4 macro parser must, however, be tagged in the same directory where these tools have been run. This is because the
       line  directives  that  ocamllex  and  ocamlyacc  put  into generated files are relative to the current working directory of the generating
       process. For the camlp4 macro parser an INCLUDE directive may be resolved relative to the current working directory of the camlp4  process.
       Therefore, if you tag such files from a different directory you will get an error message.

       When  tagging whole directory trees recursively, one can specify exceptions from the current parser list in a parser hints file, see option
       -parser-hints and PARSING HINTS FILES below.

       Tag files can contain absolute and/or relative file names.  Otags uses the file names from the command line for the tags file.	Specifying
       relative  file  names  on the command line will therefore give you a tag file with relative file names. Obviously, a tag file with relative
       file names will only work if it is located in the directory where otags was started.  Otags supports writing a tags file with relative file
       names in a parent directory via option -add-path, see EXAMPLES below.

STATIC OPTIONS

       Static options take effect on the whole program run, regardless of their position in the command line.

       -r     Descend into directories. With this option, if one of the FILE arguments is a directory otags will recursively tag all files in this
	      whole directory tree.

       -o file
	      Write tags to file.  The default is TAGS (for emacs) and tags for vi (if the -vi option is given) in the current directory. If  file
	      is a dash ( - ) the tags are written to standard output.

       -a     Append to an existing TAGS file (does only work for emacs TAGS files).

       -vi    Generate tags for vi and change the default output file into tags.

       -I dir Add directory dir to the camlp4 search path for object files for external camlp4 parsing calls.

       -add-path path
	      Add  path  at  the front of every relative file name in the tags file.  Useful when you want to put the tags file in a parent direc-
	      tory.

       -parser-hints file
	      Apply the parser hints in the specified file. Whenever otags tags a file that appears in a parser hints file, it	uses  the  parsers
	      specified there instead of the current parser list, see PARSING HINTS FILES below.

       -version
	      Print version and exit.

       -v     Verbose.	Print  file names as they are parsed and the command lines for externally started camlp4 parsing processes (if any). If -v
	      is the first command line argument backtraces for exceptions are enabled and printed if an exception escapes  and  terminates  otags
	      (which is considered as a bug about which I would appreciate a bug report).

       -q     Be quiet.

       -help  Print the option list.

       --help Alias for -help

DYNAMIC OPTIONS

       Dynamic options do only affect arguments that follow them on the command line.

       -intf FILE
	      Parse and tag FILE as an interface.

       -impl FILE
	      Parse and tag FILE as implementation.

       -pc    Clear the current parser list.

       -pa parser
	      Add  parser to the current parser list.  If parser is not one of the standard parsers that are distributed with camlp4 then the fol-
	      lowing file(s) are parsed in separate camlp4 process(es).  parser must be accepted by camlp4 -parser, that is, it must be a standard
	      camlp4 parser name or a bytecode file (.cmo) or library (.cma).

       -pr    Reset the current parser list to its default value (parse standard OCaml without extensions).

       -pp    Print the current parser list.

       -extern
	      Force otags to parse all the following files with an external camlp4 process.

       -intern
	      Switch back to (default) internal parsing.

PARSING HINTS FILES

       Parsing	hints  files are simple text files that specify parsers for certain files. This is useful when tagging recursively with option -r.
       Here is an example for some files from the OCaml distribution:

	   oq:
		camlp4/examples/parse_files.ml
	   o rq g:
		camlp4/examples/macros.ml
		camlp4/examples/arith.ml
	   rf debug:
		camlp4/Camlp4Bin.ml
		camlp4/mkcamlp4.ml
		camlp4/camlp4prof.ml
		camlp4/camlp4prof.mli

       The format of parser hints files is as follows. Empty lines and lines starting with ``#'' are ignored. A parser hints file consists  of	an
       arbitrary number of sections. Each section starts with a colon terminated line that specifies the parser to use with a space separated list
       of parser names (like those accepted by option -pa).  The remainder of the section contains file names, one per line.  Leading and trailing
       white space is ignored.

EXAMPLES

       Tag some files in the original and some in the revised syntax:

	      otags original.ml -pc -pa r revised.ml -pr original.ml

       The  -pc  is necessary because, for camlp4, the original OCaml syntax is an extension of the revised syntax. Therefore, the default current
       parser list contains the parser r already and adding r would not change the current parser list.

       Tag files with quotations (original host syntax and revised quotation syntax):

	      otags -pa rq qotation.ml

       Tag files that use the sexplib extension:

	      otags -I /usr/lib/ocaml/type-conv -I /usr/lib/ocaml/sexplib -pa pa_type_conv.cmo -pa pa_sexp_conv.cmo use_sexp.ml

       The -I options specify the directories where pa_type_conv.cmo and pa_sexp_conv.cmo are located on the system.

       Tag files in a subdirectory keeping the tags file in parent directory

	      cd subdir; otags -o ../TAGS -add-path subdir ...

       This complicated procedure is only necessary if there are files inside subdir with line directives  containing  relative  file  names  (for
       instance,  generated  by ocamllex or ocamlyacc running inside subdir) and when there are other sudirectories whose material should be added
       to ../TAGS.  If there are no files with relative line directives one can simply use "otags -r" in  the  directory  containing  subdir.	If
       there are no other subdirectories one could put the tags file into subdir without using -o or -add-path.

STANDARD CAMLP4 PARSING EXTENSIONS
       There  is  currently  no  documentation on the names and aliases that refer to standard camlp4 parsing modules. Also the dependencies among
       those modules is mostly undocumented. The only source for information is the file camlp4/Camlp4Bin.ml in the OCaml distribution.

       The following list describes the identifiers that camlp4 -parser treats specifically.  This  is	therefore  the	list  of  standard  camlp4
       parsers.  For  these identifiers case is not significant (they are piped through String.lowercase before matching). The dependencies listed
       here are treated auto-magically by camlp4 and otags.

       r, ocamlr, ocamlrevised, pa_r.cmo, camlp4ocamlrevisedparser.cmo
	      Revised syntax without stream parsers.

       rr, reloaded, ocamlreloaded, camlp4ocamlreloadedparser.cmo
	      Variant of the revised syntax (usage unknown).

       o, ocaml, pa_o.cmo, camlp4ocamlparser.cmo
	      Original syntax without stream parsers. Depends on parser r.

       rp, rparser, pa_rp.cmo, camlp4ocamlrevisedparserparser.cmo
	      Revised syntax with stream parsers. (See bug #5134 for OCaml 3.12.0 and earlier.)  Depends on parser r.

       op, parser, pa_op.cmo, camlp4ocamlparserparser.cmo
	      Original syntax with stream parsers. Depends on parser r, o, rp

       g, grammar, pa_extend.cmo, pa_extend_m.cmo, camlp4grammarparser.cmo
	      Grammar extensions.

       m, macro, pa_macro.cmo, camlp4macroparser.cmo
	      Macros and conditionals.

       q, camlp4quotationexpander.cmo
	      Reflective Quotations. This parsing extension takes the current host syntax and adds quotation expanders using that  current  syntax
	      such  that  the resulting grammar is reflective: Changing the host syntax afterwards does also affect the quotation syntax.  Depends
	      on module Camlp4QuotationCommon (common quotation infrastructure).

       rq, q_mlast.cmo, camlp4ocamlrevisedquotationexpander.cmo
	      Revised Quotations. Adds quotations in the revised syntax.  Host	and  quotation	parsing  remain  independent.  Depends	on  module
	      Camlp4QuotationCommon (common quotation infrastructure).

       oq, camlp4ocamloriginalquotationexpander.cmo
	      Original OCaml with original quotations. Loads original OCaml (without stream parsers) as host syntax and as quotation syntax.  Host
	      and quotation syntax are independent (not reflective).  Depends on parser ocamlr, ocaml and module Camlp4QuotationCommon

       rf     Full revised. Sets up revised syntax with stream parsers, grammar extensions, list comprehensions and  macros  and  adds	reflective
	      quotations. Depends on parsers/modules r, rp, Camlp4QuotationCommon, q, g, comp, m.

       of     Original	full.  Sets  up original OCaml with stream parsers, grammar extensions, list comprehensions and macros and adds reflective
	      quotations (i.e., quotations are in original syntax).  (See bug #5129 for OCaml 3.12.0 and earlier.)  Depends on parsers/modules	r,
	      o, rp, op, Camlp4QuotationCommon, q, g, comp and m.

       comp, camlp4listcomprehension.cmo
	      List comprehensions.

       debug, camlp4debugparser, camlp4debugparser.cmo
	      Debugging  statements  debug  and  camlp4_debug.	The expansion of those statements depends on the value of the environment variable
	      STATIC_CAMLP4_DEBUG such that also the produced tag entries might depend on this variable.

DIAGNOSTICS

       Parse errors are reported with normal camlp4 error messages. No tags are generated for files that produce errors.  Tagging  continues  with
       the next file, in this case.

       The  error  "Original  source  not  available" is reported if the file to which a line directive refers cannot be found. This may happen if
       otags is started in a different directory than the program that generated the faulting file.

       Otags exists with "Parser list empty for ..." when attempting to process a file with an empty current parser list.  This  happens  when	no
       -pa option follows -pc.

       Otags prints "Toplevel directive found in ... Skip file." for files containing toplevel directives. The problem is that the location infor-
       mation in the abstract syntax tree is incorrect after toplevel directives, see bug #5127.

       Escaping exceptions and assertions that terminate otags are considered as bugs. If they occur, please use option -v as first  command  line
       switch to obtain an exception backtrace and submit this with all relevant information as bug report.

EXIT STATUS

       0      everything went OK

       1      a parse error or some other error occurred and otags skipped the affected file

       2      absurd command line arguments caused otags to terminate prematurely

       3      some bug caused a crash, from which otags could only marginally recover

BUGS

       When  otags  uses an external camlp4 process for parsing, the abstract syntax tree is sent to otags as marshaled value using the DumpCamlp4
       printer. Because the magic numbers have not been changed since apparently 2006 (see bug #5481), otags cannot detect an incompatible  camlp4
       version. Therefore, otags is likely to produce segmentation faults when you change the camlp4 executables in place.

MISSING FEATURES

       Appending to vi tags files requires to reread the existing tags file, because vi tags files are sorted.

CREDITS

       Cuihtlauac  Alvarado  and Jean-Francois Monin were the first to exploit camlp4 for tagging OCaml files. This version is a complete rewrite,
       based on the new camlp4 from OCaml version 3.10 and onwards.

AUTHOR

       Hendrik Tews <otags at askra.de>

SEE ALSO

       etags(1), ctags(1)

OTAGS
								    August 2010 							  OTAGS(1)