Setup and use a Menhir parser for the OCaml grammar (REBASE POINT)

Uses the new $symbolstartpos feature of Menhir
to get locations identical to the OCamlYacc ones.

REBASE POINT: at the point of this commit, using a diff program
on parser.mly and parser_menhir.mlyp should give identical results
after the header code. If you rebase the Menhir-parser patchset
against a newer ocamlyacc parser (parser.mly), those two files
will have diverged, and you need to merge the parser.mly change
back into parser_menhir.mlyp -- and then deal with them in the
rest of the patch series.

Makefile

@@ -79,6 +79,7 @@ UTILS=utils/config.cmo utils/build_path_prefix_map.cmo utils/misc.cmo \
 PARSING=parsing/location.cmo parsing/longident.cmo \
   parsing/docstrings.cmo parsing/syntaxerr.cmo \
   parsing/ast_helper.cmo parsing/parser.cmo \
+  parsing/menhirLib.cmo parsing/parser_menhir.cmo \
   parsing/lexer.cmo parsing/parse.cmo parsing/printast.cmo \
   parsing/pprintast.cmo \
   parsing/ast_mapper.cmo parsing/ast_iterator.cmo parsing/attr_helper.cmo \
@@ -1059,6 +1060,29 @@ ocamlyacc:
 clean::
 	$(MAKE) -C yacc clean
 
+# The Menhir-generated parser
+
+# In order to avoid a build-time dependency on Menhir,
+# we store the result of the parser generator (which
+# are OCaml source files) and Menhir's runtime libraries
+# (that the parser files rely on) in boot/
+parsing/parser_menhir.ml: boot/menhir/parser_menhir.ml
+	cp $< parsing
+parsing/parser_menhir.mli: boot/menhir/parser_menhir.mli
+	cp $< parsing
+parsing/menhirLib.ml: boot/menhir/menhirLib.ml
+	cp $< parsing
+parsing/menhirLib.mli: boot/menhir/menhirLib.mli
+	cp $< parsing
+
+# Makefile.menhir exports an promote-menhir rule that calls Menhir on
+# the current grammar and refreshes the boot/ files. It must be called
+# for any modification of the grammar to be taken into account by the
+# compiler.
+include Makefile.menhir
+
+partialclean:: partialclean-menhir
+
 # OCamldoc
 
 .PHONY: ocamldoc

parsing/parse.ml

@@ -65,3 +65,11 @@ and use_file = wrap Parser.use_file
 and core_type = wrap Parser.parse_core_type
 and expression = wrap Parser.parse_expression
 and pattern = wrap Parser.parse_pattern
+
+let implementation_menhir = wrap Parser_menhir.implementation
+and interface_menhir = wrap Parser_menhir.interface
+and toplevel_phrase_menhir = wrap Parser_menhir.toplevel_phrase
+and use_file_menhir = wrap Parser_menhir.use_file
+and core_type_menhir = wrap Parser_menhir.parse_core_type
+and expression_menhir = wrap Parser_menhir.parse_expression
+and pattern_menhir = wrap Parser_menhir.parse_pattern

parsing/parse.mli

@@ -22,3 +22,11 @@ val use_file : Lexing.lexbuf -> Parsetree.toplevel_phrase list
 val core_type : Lexing.lexbuf -> Parsetree.core_type
 val expression : Lexing.lexbuf -> Parsetree.expression
 val pattern : Lexing.lexbuf -> Parsetree.pattern
+
+val implementation_menhir : Lexing.lexbuf -> Parsetree.structure
+val interface_menhir : Lexing.lexbuf -> Parsetree.signature
+val toplevel_phrase_menhir : Lexing.lexbuf -> Parsetree.toplevel_phrase
+val use_file_menhir : Lexing.lexbuf -> Parsetree.toplevel_phrase list
+val core_type_menhir : Lexing.lexbuf -> Parsetree.core_type
+val expression_menhir : Lexing.lexbuf -> Parsetree.expression
+val pattern_menhir : Lexing.lexbuf -> Parsetree.pattern

tools/Makefile

@@ -126,7 +126,9 @@ CSLPROF=ocamlprof.cmo
 CSLPROF_IMPORTS=config.cmo build_path_prefix_map.cmo misc.cmo identifiable.cmo \
   numbers.cmo arg_helper.cmo clflags.cmo terminfo.cmo \
   warnings.cmo location.cmo longident.cmo docstrings.cmo \
-  syntaxerr.cmo ast_helper.cmo parser.cmo lexer.cmo parse.cmo
+  syntaxerr.cmo ast_helper.cmo \
+  parser.cmo menhirLib.cmo parser_menhir.cmo \
+  lexer.cmo parse.cmo
 
 $(call byte_and_opt,ocamlprof,$(CSLPROF_IMPORTS) profiling.cmo $(CSLPROF),)