2 parse-scm -- Parse a single SCM expression exactly.
4 source file of the GNU LilyPond music typesetter
6 (c) 2004--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
9 #include "parse-scm.hh"
14 #include "lily-parser.hh"
15 #include "international.hh"
17 #include "paper-book.hh"
18 #include "source-file.hh"
20 /* Pass string to scm parser, evaluate one expression.
21 Return result value and #chars read.
23 Thanks to Gary Houston <ghouston@freewire.co.uk> */
25 internal_ly_parse_scm (Parse_start
*ps
)
27 Source_file
*sf
= ps
->start_location_
.get_source_file ();
28 SCM port
= sf
->get_port ();
30 int off
= ps
->start_location_
.start () - sf
->c_str ();
32 scm_seek (port
, scm_long2num (off
), scm_long2num (SEEK_SET
));
33 SCM from
= scm_ftell (port
);
35 scm_set_port_line_x (port
, scm_from_int (ps
->start_location_
.line_number () -1));
36 scm_set_port_column_x (port
, scm_from_int (ps
->start_location_
.column_number () -1));
38 SCM answer
= SCM_UNSPECIFIED
;
39 SCM form
= scm_read (port
);
41 SCM to
= scm_ftell (port
);
42 ps
->nchars
= scm_to_int (to
) - scm_to_int (from
);
45 /* Read expression from port. */
46 if (!SCM_EOF_OBJECT_P (form
))
50 static SCM module
= SCM_BOOL_F
;
51 if (module
== SCM_BOOL_F
)
53 SCM function
= ly_lily_module_constant ("make-safe-lilypond-module");
54 module
= scm_call_0 (function
);
57 // We define the parser so trusted Scheme functions can
58 // access the real namespace underlying the parser.
60 scm_module_define (module
, ly_symbol2scm ("parser"),
61 ps
->parser_
->self_scm());
62 answer
= scm_eval (form
, module
);
65 answer
= scm_primitive_eval (form
);
68 /* Don't close the port here; if we re-enter this function via a
69 continuation, then the next time we enter it, we'll get an error.
70 It's a string port anyway, so there's no advantage to closing it
72 // scm_close_port (port);
78 catch_protected_parse_body (void *p
)
80 Parse_start
*ps
= (Parse_start
*) p
;
82 return internal_ly_parse_scm (ps
);
86 parse_handler (void *data
, SCM tag
, SCM args
)
88 Parse_start
*ps
= (Parse_start
*) data
;
90 ps
->start_location_
.error (_ ("GUILE signaled an error for the expression beginning here"));
92 if (scm_ilength (args
) > 2)
93 scm_display_error_message (scm_cadr (args
), scm_caddr (args
), scm_current_error_port ());
95 if (tag
== ly_symbol2scm ("read-error"))
102 protected_ly_parse_scm (Parse_start
*ps
)
105 Catch #t : catch all Scheme level errors.
107 return scm_internal_catch (SCM_BOOL_T
,
108 &catch_protected_parse_body
,
110 &parse_handler
, (void *) ps
);
113 bool parse_protect_global
= true;
114 bool parsed_objects_should_be_dead
= false;
116 /* Try parsing. Upon failure return SCM_UNDEFINED.
117 FIXME: shouldn't we return SCM_UNSCPECIFIED -- jcn */
119 ly_parse_scm (char const *s
, int *n
, Input i
, bool safe
, Lily_parser
*parser
)
123 ps
.start_location_
= i
;
127 SCM ans
= parse_protect_global
? protected_ly_parse_scm (&ps
)
128 : internal_ly_parse_scm (&ps
);