From ac4e202fc3afcea4e7698413ce8b4764fcdc4f6b Mon Sep 17 00:00:00 2001 From: Raphael 'kena' Poss Date: Wed, 6 Oct 2010 22:52:44 +0200 Subject: [PATCH] Add support for resetting '__file__' and '__line__'. * src/input.c (reset_line, reset_file): Add functions to reset the current location. * src/m4.h: Declare them. * src/builtin.c (m4___file__, m4___line__): Use them. * doc/m4.texinfo (Location): Document the new feature. Add a test. * NEWS: Document the new feature. --- ChangeLog | 12 ++++++++++++ NEWS | 1 + doc/m4.texi | 32 +++++++++++++++++++++++++++++++- src/builtin.c | 26 ++++++++++++++++++++------ src/input.c | 19 +++++++++++++++++++ src/m4.h | 5 +++++ 6 files changed, 88 insertions(+), 7 deletions(-) diff --git a/ChangeLog b/ChangeLog index 5643bea..97ff1a5 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2014-10-17 Raphael 'kena' Poss + + Add support for resetting '__file__' and '__line__'. + * src/input.c (reset_line, reset_file): Add functions to reset the + current location. + * src/m4.h: Declare them. + * src/builtin.c (m4___file__, m4___line__): Use them. + + * doc/m4.texinfo (Location): Document the new feature. Add a + test. + * NEWS: Document the new feature. + 2014-05-13 Eric Blake doc: fix line-wrapped macro definitions diff --git a/NEWS b/NEWS index 029b34a..2bbc7c8 100644 --- a/NEWS +++ b/NEWS @@ -2,6 +2,7 @@ GNU M4 NEWS - User visible changes. * Noteworthy changes in release ?.? (????-??-??) [?] +** Add support for resetting '__file__' and '__line__'. * Noteworthy changes in release 1.4.17 (2013-09-22) [stable] diff --git a/doc/m4.texi b/doc/m4.texi index 2960cff..973d6cf 100644 --- a/doc/m4.texi +++ b/doc/m4.texi @@ -6992,7 +6992,9 @@ @samp{f} and @samp{l} flags of @code{debugmode} (@pxref{Debug Levels}), also use this notion of current file and line. Redefining the three location macros has no effect on syncline, debug, warning, or error -message output. +message output, +although the line numbers and file names can be reset as described +below. This example reuses the file @file{incl.m4} mentioned earlier (@pxref{Include}): @@ -7050,6 +7052,34 @@ @result{}6 @end example +The @code{@w{__file__}} and @code{@w{__line__}} macros take an optional +argument which allow to reset the current input file name and line +number, respectively. If @option{-s} is enabled, a synchronization line +will be emitted at the next newline in the input. Input line numbers +will autoincrement from the new value, and the file name will stay +active for the current input source until the input source is exhausted +or the name is reset again. This feature can be used when the input to +M4 already contains synchronization information, as when M4 is used as a +filter between a preprocessor and a compiler. + +@comment options: -s +@example +$ @kbd{m4 -s} +foo __line__(42)bar __line__ +baz __line__ +__line__ +@result{}#line 1 "stdin" +@result{}foo bar 42 +@result{}#line 43 +@result{}baz 43 +@result{}44 +foo __file__(`newname')bar __file__ +baz __file__ +@result{}foo bar newname +@result{}#line 46 "newname" +@result{}baz newname +@end example + The @code{@w{__program__}} macro behaves like @samp{$0} in shell terminology. If you invoke @code{m4} through an absolute path or a link with a different spelling, rather than by relying on a @env{PATH} search diff --git a/src/builtin.c b/src/builtin.c index e101838..c4fe0d5 100644 --- a/src/builtin.c +++ b/src/builtin.c @@ -1495,19 +1495,33 @@ m4_errprint (struct obstack *obs, int argc, token_data **argv) static void m4___file__ (struct obstack *obs, int argc, token_data **argv) { - if (bad_argc (argv[0], argc, 1, 1)) + if (bad_argc (argv[0], argc, 0, 2)) return; - obstack_grow (obs, lquote.string, lquote.length); - obstack_grow (obs, current_file, strlen (current_file)); - obstack_grow (obs, rquote.string, rquote.length); + if (argc > 1) + reset_file (ARG (1)); + else + { + obstack_grow (obs, lquote.string, lquote.length); + obstack_grow (obs, current_file, strlen (current_file)); + obstack_grow (obs, rquote.string, rquote.length); + } } static void m4___line__ (struct obstack *obs, int argc, token_data **argv) { - if (bad_argc (argv[0], argc, 1, 1)) + int line; + + if (bad_argc (argv[0], argc, 0, 2)) return; - shipout_int (obs, current_line); + if (argc > 1) + { + if (!numeric_arg (argv[0], ARG (1), &line)) + return; + reset_line (line); + } + else + shipout_int (obs, current_line); } static void diff --git a/src/input.c b/src/input.c index 80d5b34..5d84a3e 100644 --- a/src/input.c +++ b/src/input.c @@ -1154,3 +1154,22 @@ lex_debug (void) print_token ("lex", t, &td); } #endif /* DEBUG_INPUT */ + +/*---------------------------------. + | Reset the current line counter. | + `--------------------------------*/ +void reset_line(int line) +{ + isp->line = line; + input_change = true; +} + +/*-------------------------------. + | Reset the current file title. | + `------------------------------*/ +void reset_file(const char *title) +{ + isp->file = (char *) obstack_copy0 (&file_names, title, strlen (title)); + output_current_line = -1; + input_change = true; +} diff --git a/src/m4.h b/src/m4.h index 0889d91..f7e772d 100644 --- a/src/m4.h +++ b/src/m4.h @@ -461,6 +461,11 @@ extern void expand_format (struct obstack *, int, token_data **); extern void produce_frozen_state (const char *); extern void reload_frozen_state (const char *); +/* File: input.c --- input sources. */ + +void reset_line (int); +void reset_file (const char *); + /* Debugging the memory allocator. */ #ifdef WITH_DMALLOC -- 1.8.2.2