* ada-exp.y: Considerable reorganization to move functionality

	* ada-exp.y: Considerable reorganization to move functionality
	from ada-lex.l to here, where it is logically more appropriate.
	The original reason, however, was to prevent premature name
	lookups for selector names in record aggregates.
	(BLOCKNAME, TYPENAME, OBJECT_RENAMING): Remove; lexer now returns
	NAME for all of these.
	(VAR): New artificial token to clarify precedence rules.
	(OTHERS): New lexeme.
	(empty_stoken): New symbol.
	(%union): Remove ssym, voidval.
	(%type): Remove <voidval> type declarations.
	(syntax definitions): Add aggregates.
	Remove distinction between NAME, TYPENAME, BLOCKNAME, OBJECT_RENAMING.
	Rename some non-terminals to be closer to reference manual usage.
	Tighten up expression syntax to disallow certain non-Ada
	constructions such as X and then Y or else Z.
	(ada_parse): Remove initialization of left_block_context.
	(write_var_from_name): Remove.
	(write_var_or_type): New function, containing previous code from
	defunct write_var_from_name and name_lookup.
	(block_lookup): New function, moved from ada-lex.l
	(select_possible_type_sym): New function, factored out of
	name_lookup, which used to be in ada-lex.l.
	(find_primitive_type): Ditto.
	(chop_selector): Ditto.
	(write_ambiguous_var): New function, factored out of defunct
	write_var_from_name.
	(write_selectors): New function.
	(write_name_assoc): New function.
	(write_exp_op_with_string): New function.

	* ada-lex.l (processId): Change interface to return stoken.
	(tempbuf, resize_tempbuf, tempbuf_size, tempbuf_len): Remove.
	(block_lookup, name_lookup): Remove.  Functionality moved to
	ada-exp.y.
	(state IN_STRING): Remove.
	(rules): Handle string escapes in processString.
	Add 'others' token.
	Return all NAMEs, BLOCKNAMEs, OBJECT_RENAMINGs, TYPENAMEs in
	yylval.sval (as simple strings).
	All name look-ups now handled in ada-exp.y.
	Introduce "::" (COLONCOLON) token and return as separate token.
	(processId): Change return convention.  Comment.
	Leave leading "'" in place.
	(processString): New function.
	(find_dot_all): Add note to comment.
	Fix problem that allowed match only at the end.

	* ada-lang.c: Introduce aggregates.
	(find_struct_field): Add new parameter to count fields skipped, and
	allow other output parameters to be NULL.
	(value_tag_from_contents_and_address, ada_value_struct_elt): Use
	new find_struct_field.
	(ada_index_struct_field, assign_aggregate, ada_is_array_type)
	(num_visible_fields, ada_index_struct_field_1, ada_index_struct_field)
	(num_component_specs, assign_component, assign_aggregate):
	(aggregate_assign_from_choices,aggregate_assign_positional)
	(aggregate_assign_others,add_component_interval):
	New functions.
	(ada_evaluate_subexp): Declare.
	Add aggregate-related operators.
	(ada_forward_operator_length): Declare.
	(resolve_subexp): Add cases for new aggregate operators and OP_NAME.
	Consolidate Ada operators, using ada_forward_operator_length.
	(ada_search_struct_field): Search in forward order.
	(ADA_OPERATORS): Add new aggregate operators.
	(ada_operator_length, ada_op_name, ada_forward_operator_length)
	(ada_dump_subexp_body, ada_print_subexp): Handle new aggregate
	operators and OP_NAME.
	(ada_type_of_array): Use longest_to_int.
	(value_assign_to_component): New function.
	(ada_forward_operator_length, ada_op_name, ada_dump_subexp_body):
	Add OP_NAME case.
	(ada_forward_operator_length, ada_dump_subexp_body):
	Add OP_STRING case.

	* ada-lang.h (enum ada_operator): Add OP_AGGREGATE, OP_OTHERS,
	OP_CHOICES, OP_DISCRETE_RANGE, OP_POSITIONAL.