path: root/ChangeLog

2009-10-16  Kaz Kylheku  <kkylheku@gmail.com>

	Version 016

	Catch clauses with parameters.

	Directive for throwing exceptions: throw.

	Directive for defining exception types: defex.

	-f option renamed to -c.

	* txr.c: (version): Bump to 016
	* txr.1: Bump version to 016.

2009-10-16  Kaz Kylheku  <kkylheku@gmail.com>

	* txr.c (help, main): Changed -f argument to -c. This
	is consistent with the -c argument of the shell;
	-f looks like awk's -f option, which specifies a file,
	not a literal script body.

	* txr.1: Updated.

2009-10-15  Kaz Kylheku  <kkylheku@gmail.com>

	* txr.1: Grammar, spelling.

2009-10-15  Kaz Kylheku  <kkylheku@gmail.com>

	* parser.y (clauses_opt): Long overdue nonterminal added.
	(define_clause) simplified with clauses_opt.
	(try_clause): Error handling improved.
	(catch_clauses_opt): Catch and finally clauses can be empty.
	Error cases added.
	* txr.1: Updated.

2009-10-15  Kaz Kylheku  <kkylheku@gmail.com>

	* match.c (match_files): Use alist_remove1 for a one
	element removal.

2009-10-15  Kaz Kylheku  <kkylheku@gmail.com>

	* unwind.c (uw_throw): Add program prefix before
	unhandled exception text. Print it in the
	standard notation if it's not a string literal.
	* match.c (sem_error, file_err): Don't stick program
	prefix into exception text.

2009-10-15  Kaz Kylheku  <kkylheku@gmail.com>

	* unwind.c (uw_exception_subtype_p, uw_init):
	Slight change in representation for exception subtypes,
	saving one node in the list.

2009-10-15  Kaz Kylheku  <kkylheku@gmail.com>

	New throw and defex directives, catches with arguments.

	* lib.c (defex, throw): New symbol globals.
	(obj_init): Symbols interned.
	* lib.h (defex, throw): Declared.
	* match.c (match_files): Implemented throw and defex.
	Argument handling in catches.
	* unwind.c (uw_register_subtype): Returns right
	argument, so we can cleverly use it with reduce_left.
	* unwind.h (uw_register_subtype): Declaration updated.
	* txr.1: Updated.

2009-10-14  Kaz Kylheku  <kkylheku@gmail.com>

	Version 015

	Code restructuring.

	Corruption bugfix in gc-debugging code.

	The nil symbol more properly implemented.

	Semantics change: collect treated as a failed match if it
	does not collect anything.

	Bugfix in function argument reconciliation: must only
	be done for unbound parameters.

	New @(local) directive (synonym of forget) for expressing
	local variables in functions.

	Quasi-literals: backquote-delimited literals that contain interpolated
	variables. Useful in next, output, bind and function calls.

	Hygiene: some implementation-inserted syntax tree elements
	are now in their own namespace so they can't clash with user-defined
	constructs.

	Rewritten streams implementation.

	Exception handling: try/catch/finally.

	Exceptions used internally and externally.

	File errors are mapped to exceptions now.

	Hash bang (#!) scripting supported.

	New -f paramater, allowing entire query to be specified
	as argument rather than from a file or stdin.

	* txr.c: (version): Bump to 014.
	* txr.1: Bump version to 014. More documentation about
	exceptions.

2009-10-14  Kaz Kylheku  <kkylheku@gmail.com>

	Support for hash bang execution, and embedding query
	in a command line argument.

	* txr.c (remove_hash_bang_line): New function.
	(main): Added -f option. Initialize and gc-protect yyin_stream, and
	use it in all places where yyin was previously set up.
	Diagnose when -a, -D and -f are wrongly clumped with other options.
	Remove the first line of the query if it starts with #!.
	* parser.h (yyin): Declaration removed.
	(yyin_stream): Declared.
	* parser.l (YY_INPUT): Macro defined.
	(yyin_stream): New global.
	* stream.c (string_in_get_line, string_in_get_char): Bugfix:
	wrong length function used.
	(string_in_ops): Bugfix: wrong get_char function wired in.
	(get_char): New function.
	* stream.h (get_char): Declared.
	* txr.1: -f option documented.

2009-10-14  Kaz Kylheku  <kkylheku@gmail.com>

	* lib.c (obj_print, obj_pprint): Print #<garbage ...>
	syntax if an object has a bad type code; do not just return
	without printing anything.

2009-10-14  Kaz Kylheku  <kkylheku@gmail.com>

	Code cleanup and documentation.

	* txr.1: Start documenting quasiliterals, exception handling and
	nothrow in next and output.
	* parser.y (catch_clauses_opt): Add missing empty production, so that
	a try block doesn't have to have a finally clause.
	* lib.h (or2, or3, or4): New macros.
	* match.c (match_files): Allow output and next forms which just
	have one argument that is nothrow, as documented.
	* stream.c common_vformat, string_out_vcformat, string_out_vcformat,
	make_string_output_stream, make_dir_stream, close_stream, get_line,
	vformat, vcformat, format, cformat, put_string, put_cstring,
	put_char): Switch to new style type assertions.

2009-10-13  Kaz Kylheku  <kkylheku@gmail.com>

	New syntax for next and output directives, taking advantage
	of quasi-literals. Non-throwing behavior can be specified in
	both using nothrow. The old syntax is supported, and has
	the old semantics (non-throwing). Hence, the test cases
	pass again without modification.

	File open errors thrown as file_error type.

	* lib.c (nothrow, file_error): New symbol globals.
	(obj_init): New symbols interned.
	* lib.h (nothrow, file_error): Declared.
	* match.c (file_err): New function.
	(eval_form): Bugfix: if input is nil, or an atom other than a symbol,
	return the value hoisted into a cons. A nil return strictly means,
	unbound variable.
	(match_files): Support new syntax for next and and output.
	Throw open errors as file_err.
	* parser.l (grammar): Change how OUTPUT is returned to the
	style similar to DEFINE, so interior forms can be parsed.
	* parser.y (grammar): Fix up output_clause with new syntax.
	* unwind.c (uw_throw): Do not abort on unhandled file_error,
	but terminate with a failed status.
	(uw_init): Register file_error as a subtype of error exception.

2009-10-13  Kaz Kylheku  <kkylheku@gmail.com>

	First cut at working try/catch/finally implementation.

	* lib.c (try, catch, finally): New symbol globals.
	(obj_init): New symbols interned.
	* lib.h (try, catch, finally: Declared.
	* parser.y (TRY, CATCH, FINALLY): New tokens.
	(try_clause, catch_clauses_opt): New nonterminal grammar symbols.
	* parser.l (yybadtoken): TRY, CATCH and FINALLY handled.
	(grammar): New cases for try, catch and finally.
	* unwind.h (struct uw_catch): New member called visible.
	(uw_continue): New parameter added.
	(uw_exception_subtype_p): Declared.
	(uw_catch_begin): Macro rewritten to use switch logic
	around setjmp.
	(uw_do_unwind, uw_catch, uw_unwind): New macros.
	(uw_catch_end): Rewritten to close switch, and automatically
	continue the unwinding if the block is entered as an unwind.
	* unwind.c (uw_unwind_to_exit_point): Exception catching
	frames made invisible via new flag prior to control passing to them.
	longjmp code 2 introduced for distinguishing a catch from
	an unwind. Visibility flag is checked and invisible frames
	are skipped.
	(uw_push_catch): cont member of the unwind frame initialized to zero.
	(exception_subtype_p): Renamed to uw_exception_subtype_p, changed
	to extern. Fixed wrong order of arguments to assoc.
	(uw_throw): Honor visibility flag: do not consider invisible
	catch frames.
	(uw_register_subtype): sup/sub mixup bugfix.
	(uw_continue): Takes extra argument: the continuation frame
	that (re)establishes the exit point for the unwinding.
	This allows nested unwinding action to take place in a finally,
	and then to continue to the original exit point.
	* match.c (match_files): Handling for try directive added.

2009-10-13  Kaz Kylheku  <kkylheku@gmail.com>

	* parser.l (yybadtoken): Bugfix: added missing LITCHAR case.
	* unwind.h (internal_error): Fixed broken macro.
	* match.c (match_line, match_files): sem_error bugfix: used %a instead
	of ~a.
	(match_files): Wrap block handler in compound statement, otherwise the
	macroexpansion declares a variable in the middle of a statement, which
	is a gcc extension to C90 (or a C99 feature,
	but we aren't using C99).

2009-10-08  Kaz Kylheku  <kkylheku@gmail.com>

	Exception handling for query errors.
	Verbose logging decoupled from yyerror functions.
	Superior object-oriented formatting used for cleaner code.

	* lib.c (query_error): New symbol global.
	(obj_init): New symbol interned.
	* lib.h (query_error): Declared.
	* match.c (output_produced): Variable changed to external linkage.
	(debugf, debuglf, debuglcf, sem_error): New static functions.
	(dest_bind, match_line, match_files): Regtargetted away from
	the yyerrorf and yyerrorlf functions to use debugf,
	debuglf, debuglcf for logging and sem_error for throwing
	query errors as exceptions.
	* parser.h (spec_file_str): New global declared.
	* parser.l (yyerror): Calls yyerrorf instead of yyerrorlf;
	lets yyerrorf increment error count.
	(yyerrorf): Loses level argument.
	(yyerrorlf): Function removed.
	(yybadtoken): Retargetted from yyerrorlf to yyerrorf.
	(grammar): yyerrorf call fixed up.
	* txr.c (spec_file_str): New global defined.
	(main): Protects new global against gc, and initializes it.
	* unwind.c (uw_throw): If an unhandled exception is of
	type query_error, it results in an exit rather than abort.
	The false string is conditionally printed.
	(uw_init): Register query_error as subtype of error.

2009-10-08  Kaz Kylheku  <kkylheku@gmail.com>

	Exception handling framework implemented.

	* lib.c (cobj_t, error, type_error, internal_err, numeric_err,
	range_err): New symbol globals.
	(prog_string): New string global.
	(code2type): New static function.
	(typeof): Rewritten using code2type.
	(type_check, type_check2): New static functions.
	(car, cdr, list, plus, minus, length_str, chr_p, chr_str,
	chr_str_set, apply, funcall, funcall1, funcall2,
	vec_get_fill, vecref_l, lazy_stream_cons): Checks and
	assertions rewritten using new functions and macros.
	(obj_init): prog_string protected from gc.
	New symbols interned.
	(init): uw_init() call moved after obj_init() because
	it needs stable symbols.
	* lib.h (cobj_t, error, type_error, internal_err, numeric_err,
	range_err, prog_string, type_check, type_check2): Declared.
	* match.c (dump_var, complex_snarf, complex_close): abort
	calls rewritten to use exception handling.
	* regex.c (nfa_all_states, nfa_closure, nfa_move): Likewise.
	* stream.c (string_out_vcformat): Bugfix: fill index not updated.
	(make_string_output_stream): Bugfix: initial buffer not null terminated.
	(get_string_from_stream): New function.
	* stream.h (get_string_from_stream): Declared.
	* txr.c (main): Some error prints turned to throws.
	* unwind.c (unwind_to_exit_point): Supports UW_CATCH frames,
	whose finalization logic has to be invoked during unwinding,
	and as target exit points.
	(uw_init): Installs exception symbols into
	subtyping hirearchy.
	(uw_push_catch, exception_subtype_p, uw_throw, uw_throwf,
	uw_errorf, uw_throwcf, uw_errorcf, type_mismatch,
	uw_register_subtype, uw_continue): New functions.
	(exception_subtypes): New static global.
	* unwind.h (noreturn): New macro, conditionally defined on __GNUC__.
	(enum uw_frtype): New member, UW_CATCH.
	(struct uw_catch): New struct type.
	(union uw_frame): New member, ca.
	(uw_push_catch, exception_subtype_p, uw_throw, uw_throwf,
	uw_errorf, uw_throwcf, uw_errorcf, type_mismatch,
	uw_register_subtype, uw_continue): New functions declared.
	(uw_catch_begin, uw_catch_end, internal_error, type_assert,
	bug_unless, numeric_assert, range_bug_unless): New macros.

2009-10-07  Kaz Kylheku  <kkylheku@gmail.com>

	Rewritten streams implementation.

	* stream.h, stream.c: New files.
	* Makefile (OBJS): New object file stream.o.
	* dep.mk: Dependencies updated.
	* gc.c (finalize): STREAM case removed.  Call destroy only if not null.
	(mark_obj): STREAM case removed.
	* lib.c (push, pop): New functions.
	(equal): STREAM case removed.
	(sub_str): Allow from parameter to be nil, defaulting to zero.
	(stdio_line_read, stdio_line_write, stdio_close, stdio_line_stream,
	pipe_close, pipe_line_stream, dirent_read, dirent_close,
	dirent_stream, stream_get, stream_pushback, stream_put,
	stream_close): Functions removed.
	(stream_ops dirent_stream_ops, stdio_line_stream_ops,
	struct stream_ops, pipe_line_stream_op): Static structs removed.
	(lazy_stream_func, lazy_stream_cons): Retargetted to new streams.
	(cobj_print_op): Likewise.
	(init): Disables and restores GC, instead of doing it in obj_init.
	(obj_print): Retargetted to new streams.
	(obj_pprint): New function.
	(obj_init): Does not manipulate gc_state any more, moved to init.
	Call to stream_init added.
	(d, snarf): Retargetted to new streams.
	(snarf_line): Removed, now appears in stream.c, retargetted
	to new streams.
	* lib.h (enum type): STREAM removed.
	(struct stream, struct stream_ops): Removed.
	(struct cobj_ops): Retargetted to new streams.
	(union obj): sm member removed.
	(push, pop, obj_pprint): Declared.
	(stdio_line_stream, pipe_line_stream, dirent_stream, stream_get,
	stream_pushback, stream_put, stream_close, snarf_line): Removed.
	(cobj_print_op, dump, snarf): Modified.
	* match.c (dump_bindings, complex_snarf): Retargetted to new streams.
	* txr.c (main): format used to dump bindings and specs in verbose mode.

2009-10-07  Kaz Kylheku  <kkylheku@gmail.com>

	Implemented quasi-literals: string literals which may
	contain variables to be interpolated.

	Also, took care of a hygiene problem with respect to some
	parser-generated forms, which must be invisible to the user.

	* Makefile (LEX_DB_FLAGS): New variable; helpful
	in generating a lexical analyzer with debug tracing.
	* parser.l (nesting, closechar): Static variables removed.
	(char_esc): Add \` escape for quasi-literals.
	(stack): New %option, to generate a scanner which has
	a start condition stack.
	(QSILIT): New start condition.
	(grammar): Refactored to use start condition stacks.
	Quasi-literal lexical analysis added.
	* parser.y (lit_char_helper): New function, for factoring out
	some common logic between string literals and quasi literals.
	(quasilit, quasi_item, quasi_items): New grammar symbols and
	production rules.
	(strlit): Rule shortened with new helper function.
	Bugfix: error case assigns nil to $$.
	(chrlist): Bugfix: error case assigns nil to $$.
	(LITCHAR): Added to %prec table to fix shift-reduce problem.
	(expr): Production now can generate a quasilit.
	* lib.c (quasi): New symbol global.
	(obj_init): Intern quasi as "$quasi", so the user can
	make a function called quasi.  Also, var and regex are now interned
	with the names "$var" and "$regex" for the same reason.
	* lib.h (quasi): Declared.
	* match.c (eval_form): Rewritten with recursive processing
	to handle deeply embedded variables, as well as quasi-strings.
	(subst_vars): Handles quasi-strings.
	(match_files): Function calls now use eval_form for function
	argument evaluation, except of course in the special case that if an
	argument is a symbol, it may be unbound.

2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	* match.c (match_files): No error message for merging to
	a symbol which is already bound; the existing behavior
	is to destructively update the binding, which is useful,
	and so the error is pointless.

2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	Introduce local as synonym to forget. It does exactly the
	same thing; a previous binding is forgotten. This spelling
	is nicer for functions.
	* lib.h (local): Declared.
	* lib.c (local): Defined.
	(obj_init): New symbol interned.

2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	Bugfix: function parameter reconciliation (after function call
	completes) must only consider the unbound parameters.
	Otherwise false mismatches result if the function destructively
	manipulated some bindings of bound parameters.
	E.g. @(define foo (a)) is called as @(foo "bar") and internally
	it rebinds bound parameter a to "baz". This situation is
	not a mismatch. The rebinding is thrown away.

	* match.c (match_files): When processing a function call,
	keep an alist which associates arguments and unbound parameters.
	Then, after the function call, process the alist, rather
	than the full parameter list.

2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	Semantics change: collect fails if it does not collect
	anything. Non-failing behavior can be obtained by
	wrapping with @(maybe) (but no such workaround for coll yet).

	* match.c (match_line): Return nil if coll collected nothing.
	(match_files): Return nil if collect collected nothing.


2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	Bugfix: nil must be on the list of interned symbols.

	* lib.c (sym_name): Function removed. This was like
	symbol_name but did not accept nil.
	(intern): Use symbol_name instead of sym_name, allowing
	nil to be on the list of interned symbols.
	(obj_init): Add nil to interned_syms list.
	(nil_string): Changed from "NIL" to "nil".
	* match.c (dest_bind): Treat nil as a value, not a symbol.
	(match_files): Treat nil as a value when it's
	a function argument.

2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	* gc.c (more): Bugfix: free_tail was incorectly calculated,
	thereby destroying the validity of the FIFO recycling algorithm
	used when GC debugging is enabled. This showed up as mysterious
	assertions and crashes.
	(mark_obj): Do not abort if a free object is marked.
	(mark_mem_region): Renamed bottom and top variables to low
	and high. The naming was confusing inverted relative
	to that in the caller.
	(sweep): Abort if somehow a block is free and marked reachable.

2009-10-06  Kaz Kylheku  <kkylheku@gmail.com>

	* match.c (match_files): Fixed nonexitent symbol warning for merge
	directive (complained about wrong symbol).

2009-10-05  Kaz Kylheku  <kkylheku@gmail.com>

	Refactoring matching code.

	* lib.h (cobj_ops): New function pointer, mark.
	* gc.c (mark_obj): For a COBJ type, call the mark function
	if the pointer is non-null.
	(gc_mark): New public function, wrapper that calls
	the private mark_obj. Implementations of mark for COBJ
	objects will need to call this.
	* gc.h (mark_obj): Declared.
	* regex.c (regex_obj_ops): Explicitly initialize mark function pointer
	 to null.

2009-10-05  Kaz Kylheku  <kkylheku@gmail.com>

	Code restructuring.

	* Makefile (match.o): New object file.
	(depend): New rule for generating dep.mk, using txr.
	(lib.o, lex.yy.o, regex.o, y.tab.o unwind.o, txr.o, match.o, gc.o):
	Dependency rules removed.
	* dep.mk: New make include file; captures dependencies. Generated
	by new depend rule in Makefile, using txr.
	* depend.txr: Txr query to generate dependencies.
	* extract.y: File renamed to parser.y
	(output_produced): Variable removed,
	moved into new file match.c.
	(dump_shell_string, dump_shell_string, dump_var, dump_bindings, depth,
	weird_merge, map_leaf_lists, dest_bind, eval_form, match_line,
	format_field, subs_vars, complex_open, complex_open_failed,
	complex_close, complex_snarf, robust_length, bind_car, bind_cdr,
	extract_vars, extract_bindings, do_output_line, do_output,
	match_files, extract): Functions removed, added to match.c.
	(struct fpip): Definition removed, added to match.c
	(<stdlib.h>, <string.h>, <ctype.h>, <errno.h>, <setjmp.h>,
	"gc.h", "unwind.h"): Unneeded headers removed.
	* match.c: New file.
	* extract.l: Renamed to parser.l.
	* extract.h: Renamed to parser.h.
	(opt_loglevel, opt_nobindings, opt_arraydims, version, progname):
	Declarations moved to txr.h.
	(extract): Dclaration moved to match.h.
	* txr.h, match.h: New headers.
	* gc.h (opt_gc_debug): Moved to txr.h.

2009-10-03  Kaz Kylheku  <kkylheku@gmail.com>

	Version 014

	New cases directive.

	New define directive: user-defined dynamically scoped functions.

	String literals in bind and function calls.

	EOF in the middle of a line handled properly.

	* extract.l (version): Bump to 014.
	* txr.1: Bump version to 014.


2009-10-02  Kaz Kylheku  <kkylheku@gmail.com>

	New cases directive.

	* extract.l (yybadtoken): Add case for CASES.
	(grammar): Tokenize cases directive.
	* extract.y (CASES): New token kind.
	(cases_clause): New grammar symbol.
	(grammar): Implement new grammar cases.
	(match_files): Implement semantics for cases.
	* lib.c (cases): New global.
	(obj_init): Intern cases symbol.
	* lib.h (cases): Declared.
	* txr.1: Documented.

2009-10-02  Kaz Kylheku  <kkylheku@gmail.com>

	Support for string and character literals.

	* extract.l (char_esc): Support \' and \" escapes.
	(STRLIT, CHRLIT): New flex start conditions.
	(grammar): New rules for tokenizing string literals.
	* extract.y (LITCHAR): New token kind.
	(strlit, chrlit, litchars): New grammar symbols.
	(grammar): Implement string literal parsing.
	(dump_var): Support character objects, treating
	them as one-character strings.
	(eval_form): New function.
	(match_files): In bind directive, allow the right
	hand side to be an arbitrary object.
	* lib.c (mkustring, init_str): New functions.
	(cat_str): Allow characters in the mix, treating
	them as one-character strings.
	* lib.h (mkustring, init_str): Declared.
	(chrp, chr_str, chr_str_set): New function.
	* txr.1: Documented.

2009-10-02  Kaz Kylheku  <kkylheku@gmail.com>

	Support for query-defined functions.

	* extract.l (yybadtoken): New DEFINE case.
	(NESTED): New flex start condition.  This allows for different lexing
	rules in nested lists, so even though for instance @(collect) is a
	special token @((collect)) isn't.
	(grammar): Refactored with NESTED.
	Tokenize define directive.
	* extract.y (define_transform): New function.
	(DEFINE): New token kind.
	(define_clause): New grammar symbol.
	(match_files): Implement define semantics, and function calls.
	* lib.c (define): New global.
	* lib.h (define): Declared.
	(proper_listp, alist_remove1, copy_cons, copy_alist): New functions.
	(obj_init): Intern define symbol.
	(init): Call new function uw_init.
	* unwind.c (toplevel_env): New static structure.
	(uw_unwind_to_exit_point): Support new UW_ENV frame type.
	(uw_init, uw_find_env, uw_push_env, uw_get_func, uw_set_func): New
	functions.
	* unwind.h (UW_ENV): New enumeration member in uw_frtype.
	(uw_dynamic_env): New struct.
	(uw_block_begin, uw_block_end): Renamed some variables.
	(uw_env_begin, uw_env_end): New macros.
	* txr.1: Documented.

2009-10-02  Kaz Kylheku  <kkylheku@gmail.com>

	Misc. bugfixes and improvements.

	* extract.l (grammar): Newline in a directive
	no longer an error. Why not allow it.
	* extract.y (grammar): Productions for catching empty bodies in some
	constructs now end with END newl, rather
	than just END, so parsing can continue sanely.
	(match_lines): In diagnostics, don't say "ignored" about material which
	causes an error that fails the query!
	* lib.c (mkstring): Initialize length since we know it!
	(c_str): Take a symbol as an arg, so we don't have
	to keep writing c_str(symbol_name(sym)).
	(obj_print): Use isprint rather than isctrl to decide
	whether to print a character as an escape.
	(snarf_line): Properly handle EOF in the middle of line.

2009-09-29  Kaz Kylheku  <kkylheku@gmail.com>

	Version 013

	Some minor garbage collection issues fixed.

	Infinite looping bug fixed.

	New @(trailer) directive.

	* extract.y (match_files): Implemented trailer directive.
	* extract.l (version): Bump to 013.
	* lib.h (trailer): Declaration added.
	* lib.c (trailer): External definition added.
	(obj_init): Initializer trailer with interned symbol.
	* txr.1: Documented @(trailer) and bumped version to 013.

2009-09-29  Kaz Kylheku  <kkylheku@gmail.com>

	Looping bug fixed. Certain directives could cause an infinite
	loop if the query has run out of data.

	* extract.y (match_files): The semantics of the first_file_parsed
	argument changes a little bit. Previously, if nil was passed,
	a new lazy stream would be opened for the first file.
	But this is ambiguous because nil also means empty list;
	sometimes when we recurse into match_files, the data has ran
	out and this argument is thus nil. Now, that argument must be
	the symbol t in order to mean ``open the first file''.
	If the argument is nil, it unambiously means ``we are at the end of the
	current file; don't open anything''.
	(extract): The initial call to match_files now passes
	the symbol t for the first_file_parsed argument.

2009-09-29  Kaz Kylheku  <kkylheku@gmail.com>

	Fixing some gc issues. The test cases were found to bomb
	with an assertion when run with --gc-debug enabled,
	due to a garbage-collected object still being used.
	This was due to the way the main function was structured.

	Also, the stack ``top'' terminology in the gc was stupidly wrong. Leaf
	function frames are at the stack top, and main is near the bottom.
	I was thinking of the ``top caller''.

	* Makefile (TXR_DBG_OPTS): New variable.
	Tests are now run with --gc-debug, which makes them slower,
	but has much greater chance of trapping gc problems.
	* extract.l (main): Two variables are now used for determining the
	stack bottom. We don't know in which order the compiler
	places local variables into a stack frame.  (This is a separate
	question from that of the direction of stack growth).
	The call to the init function is now done right away.
	The argument processing section of main does some processing
	with GC objects, but the init function was being called afterward,
	before the list of interned symbols is protected from garbage
	collection! So with --gc-debug turned on, parts of the interned
	symbol list were being garbage collected (since the variable
	has not yet been added to the set of root pointers, which is
	done in the init function).  Also, the use of an unknown --long-option
	is diagnosed properly now.
	* gc.c (gc_stack_top): Renamed to gc_stack_bottom, and converted from
	extern to static.
	(mark): Follows rename of gc_stack_top to gc_stack_bottom.
	(sweep): Eliminated the freed variable for counting freed objects,
	and the associated debug message, which was not useful.
	Commented why the free list is managed differently when dbg
	is turned on.
	(gc_init): New function.
	* gc.h (gc_stack_top): Declaration removed.
	(gc_init): Declaration added.
	* lib.c (min): New macro.
	(init): Takes two additional arguments which are used to
	determine the stack bottom. The function first determiens
	whether the stack grows up or down. Then it takes the
	greater or smaller of the two potential stack top pointers,
	based on that. The result is passed go gc_init.
	* lib.h (init): Declaration updated.

2009-09-28  Kaz Kylheku  <kkylheku@gmail.com>

	Version 012

	Semantics change of @(until) in @(collect) and @(coll).

	Minor fixes.

	* extract.y (match_line, match_files): The until clauses
	continue to be processed after the main clauses of the collect
	or coll (to see the bindings), but are processed before
	the collection occurs, so that the until will veto
	the bindings of the last iteration.  Moreover, the data
	positions stays where it is when this happens, and no
	arrangement is made to match the until material again.

	* txr.1: Tried to document the change.


2009-09-27  Kaz Kylheku  <kkylheku@gmail.com>

	* txr.1: following proofread, fixed various escaping problems and
	instances of missing text.

2009-09-26  Kaz Kylheku  <kkylheku@gmail.com>

	* lib.c (equal): Bugfixes: wrong fallthrough of FUN case.
	VEC case must return nil, not break.

2009-09-26  Kaz Kylheku  <kkylheku@gmail.com>

	Preparation for some sorting support.

	* extract.y (merge): Renamed to weird_merge.
	(map_leaf_lists): New functino.
	(match_file): Follow weird_merge rename.
	* lib.c (all_satisfy, none_satisfy, string_lt, do_bind2other,
	bind2other, merge, do_sort, sort): New functions.
	* lib.h (all_satsify, none_satisfy, string_lt,
	bind2other, sort): Declared.

2009-09-25  Kaz Kylheku  <kkylheku@gmail.com>

	Version 011

	New @(maybe) clause optionally matches (does not fail if none of
	its clauses match anything).

	New blocks feature: allows a query or subquery to be
	abruptly terminated by invoking an exit to a named or anonymous
	block. @(collect) and @(skip) have implicit anonymous blocks now.

	The @(skip) directive takes a numeric argument now, which limits
	how many lines are searched.

	* Makefile, extract.l, extract.y, extract.h, gc.c, gc.h, lib.c, lib.h,
	regex.c, regex.h, txr.1, unwind.c, unwind.h: Copyright notice and
	license text updated or added, and version bumped up to 011.
	* tests/001/query-1.txr, tests/001/query-2.txr, tests/001/query-3.txr,
	tests/002/query-1.txr: Assigned to public domain.

2009-09-25  Kaz Kylheku  <kkylheku@gmail.com>

	New features:
	- named blocks;
	- maybe clause;
	- optional iteration bound on skip.

	* extract.y: includes added: "unwind.h", <setjmp.h>.
	(MAYBE, OR): New grammar tokens.
	(maybe_clause): New nonterminal grammar symbol.
	(expr): A NUMBER can be an expression now, so that @(skip 42)
	is valid syntax.
	(match_files): Support for numeric argument in skip directive
	to bound the search to a maximum number of lines.
	Anonymous block established around skip.
	New directives implemented: maybe, block, accept and fail.
	Anonymous block established around collect.
	* txr.1: Documentation updated with new features.
	* Makefile: new object file unwind.o, and associated rules.
	* extract.l (yybadtoken): New cases for MAYBE and OR.
	(grammar): Likewise.
	* lib.c (block, fail, accept): New symbol variables.
	(obj_init): New symbols interned.
	* lib.h (block, fail, accept): Declared.
	(if2, if3): Macros fixed so test expression is not compared to nil,
	but implicitly tested as boolean.
	* unwind.c, unwind.h: New source files.

2009-09-24  Kaz Kylheku  <kkylheku@gmail.com>

	Stability fixes.

	* extract.y (match_files): Fixed invalid string("-") to
	string(chk_strdup("-")) which caused a freeing of
	a non-malloced string at gc finalization time.
	* regex.c (nfa_state_shallow_free): New function: does not
	free satellite objects, just the structure itself.
	(nfa_combine): Use nfa_state_shallow_free instead of nfa_state_free,
	because the merged state inherits ownership of objects from the state
	being spliced out.
	(nfa_state_set): Fix lack of initialization of s.visited member of the
	state structure.

2009-09-24  Kaz Kylheku  <kkylheku@gmail.com>

	Version 010

	A file specs can start with $, which means read a directory.

	Data sources are not into memory at once, but on demand,
	which can reduce memory for many queries.

	Regular expressions are now compiled once, when the
	query is parsed.

	Character escapes are now supported in regular expressions,
	and as a special syntax.

	* extract.l (version): Bumped to 010.
	(grammar): 8 and 9 are not octal digits; handle all regex
	backslash escaping in lexical grammar.
	* extract.y (grammar): Get rid of backslash handling from
	regex grammar. Lexer returns a REGCHAR for every escaped
	item. In situations where an operator character is implicily
	literal, like * in a character class, we use the grammar
	to include that alongside REGCHAR. Bugfixes: the character ], when not
	closing a class, is not a syntax error but stands for itself;
	the character - stands for itself outside of character class;
	the | character is literal in a character class.
	* txr.1: Updated version. Documented character escapes.

2009-09-24  Kaz Kylheku  <kkylheku@gmail.com>

	Lazy stream list improvement: no extra NIL element caused
	by end-of-file. Requires push-back support in streams.
	To avoid introducing a new structure member into streams,
	we extend the semantics of the label member, and rename
	it to label_pushback.

	* lib.c (stdio_line_stream, pipe_line_stream,
	dirent_stream): Follow rename of struct stream member;
	assert that label is an atom.
	(stream_get): Check pushback stack first and get item from there.
	(stream_pushback): New function.
	(lazy_stream_func): Pull one more item from the stream and
	use /that/ to decide whether to continue the lazy stream.
	The extra item is pushed back, if valid.
	(lazy_stream_cons): Simplified: no hack involving regular cons. Starts
	the induction by peeking into the stream. If something is there, it is
	pushed back, and a lazy cons is constructed which will fetch it.
	(obj_print): Made aware of the pushback, which must be skipped
	to get to the terminating label.
	* lib.h (struct stream): Member renamed from label to label_pushback.
	(stream_pushback): New function declaration.

2009-09-23  Kaz Kylheku  <kkylheku@gmail.com>

	Escape syntax in regexes, and text. The
	standard seven character escapes are supported,
	namely \a, \b, \t, \n, \v, \f, and \r,
	as well as hex and octal escapes, plus
	the code \e for ASCII ESC.

	* extract.l (char_esc, num_esc): New functions.
	(grammar): New lex cases.
	* lib.c (obj_print): Support all character escapes in printing.
	Bugfix: backslash printed as two backslashes, not one.

2009-09-23  Kaz Kylheku  <kkylheku@gmail.com>

	* tests/002/query-1.txr: Modified to use $ to scan thread
	subdirectories.
	* tests/002/query-1.expected: Updated.

2009-09-23  Kaz Kylheku  <kkylheku@gmail.com>

	New COBJ type for wrapping arbitrary C objects into the
	Lisp-like framework. Compiled regexes are objects now.
	Regexes in a query are now compiled just once.

	* extract.y (grammar): Regexes compiled while parsing.
	(match_line): Modify with respect to the abstract syntax
	tree change, and the interface changes in the match_regex,
	and search_regex functions.
	* gc.c (mark_obj, finalize): Handle marking and finalization
	of COBJ objects.
	* lib.c (typeof, equal, obj_print): Handle COBJ.
	(cobj, cobj_print_op): New functions.
	* lib.h (type_t): New enum element, COBJ.
	(struct cobj, struct subj_ops): New types.
	(union obj): New member, co.
	(cobj, cobj_print_op): New functions declared.
	* regex.c (regex_equal, regex_destroy, regex_compile, regex_nfa): New
	functions.
	(regex_obj_ops): New static struct.
	(search_regex, match_regex): Interface change. Regex arguments
	are now compiled regexes. Functions won't handle raw regexes.
	* regex.h (regex_compile, regex_nfa): New functions declared.

2009-09-23  Kaz Kylheku  <kkylheku@gmail.com>

	New feature: file specs that start with $ read directories.
	Reading from an ``ls'' pipe is too slow.

	Streams and lazy conses implemented. Lazy conses allow us to treat a
	file or other kind of stream exactly as if it were a list.
	We can use car and cdr, etc. But only the parts of the list
	that we actually touch are instantiated on-the-fly by
	reading from the underlying stream.

	* extract.l: inclusion of <dirent.h> added.
	* extract.l: inclusion of <dirent.h> added.
	* extract.y (fpip_closedir): new enumeration in struct fpip,
	and fpip_noclose removed.
	(complex_open): Check for leading $, use opendir.
	(complex_open_failed): New function.
	(complex_close): Handle fpip_closedir case. Not closing
	stdin and stdout is handled by explicit comparison now.
	(complex_snarf): New function, constructs stream of
	a suitable type, over object returned from complex_close,
	wraps it in a lazy list.
	(match_files): Use complex_snarf instead of snarf to get a lazy list.
	* gc.c: Handle LCONS and STREAM cases.
	* lib.c (stream_t, lcons_t): New variables holding symbols.
	(typeof, equal, obj_print): Handle LCONS and STREAM.
	(car, cdr, car_l, cdr_l, consp, atom, listp): Rewritten to handle
	LCONS.
	(chk_strdup, stdio_line_read, stdio_line_write, stdio_close
	stdio_line_stream, pipe_close, pipe_line_stream,
	dirent_read, dirent_close, dirent_stream,
	stream_get, stream_put, stream_close,
	make_lazycons, lazy_stream_func, lazy_stream_cons): New functions.
	(stdio_line_stream_ops, pipe_line_stream_ops,
	dirent_stream_ops): New static structs.
	(obj_init): Intern new symbols lstream, lcons, and dir.
	* lib.h (type_t): New enum members STREAM and LCONS.
	(struct stream, struct stream_ops, struct lazy_cons): New types.
	(union obj): New members sm and lc.
	(chk_strdup, stdio_line_stream, pipe_line_stream,
	dirent_stream, stream_get, stream_put, stream_close,
	lazy_stream_cons): New function declarations.
	* regex.c: inclusion of <dirent.h> added

2009-09-23  Kaz Kylheku  <kkylheku@gmail.com>

	Version 009

	User-friendly error messages from parser.
	Fixed -q option.

	* extract.l (version): Bumped to 009.
	* txr.1: Updated version.

2009-09-22  Kaz Kylheku  <kkylheku@gmail.com>

	* Makefile (LIBLEX): New variable.
	Refer to lex library as -lfl, using variable
	that can be overridden.

2009-09-22  Kaz Kylheku  <kkylheku@gmail.com>

	* extract.h (yybadtoken): New function declaration.
	* extract.l (yybadtoken): New function.
	(main): Fixed -q option.
	* extract.y (grammar): Lots of new error productions, some
	phrase rules refactored, resulting in much more user-friendly
	error diagnosis.
	* txr.1: -q option semantics clarified.