2 parse-scm -- Parse a single SCM expression exactly.
4 source file of the GNU LilyPond music typesetter
6 (c) 2004--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
9 #include "parse-scm.hh"
14 #include "international.hh"
16 #include "paper-book.hh"
17 #include "source-file.hh"
19 /* Pass string to scm parser, evaluate one expression.
20 Return result value and #chars read.
22 Thanks to Gary Houston <ghouston@freewire.co.uk> */
24 internal_ly_parse_scm (Parse_start
*ps
)
26 Source_file
*sf
= ps
->start_location_
.get_source_file ();
27 SCM port
= sf
->get_port ();
29 int off
= ps
->start_location_
.start () - sf
->c_str ();
31 scm_seek (port
, scm_long2num (off
), scm_long2num (SEEK_SET
));
32 SCM from
= scm_ftell (port
);
34 scm_set_port_line_x (port
, scm_from_int (ps
->start_location_
.line_number () -1));
35 scm_set_port_column_x (port
, scm_from_int (ps
->start_location_
.column_number () -1));
37 SCM answer
= SCM_UNSPECIFIED
;
38 SCM form
= scm_read (port
);
41 /* Reset read_buf for scm_ftell.
42 Shouldn't scm_read () do this for us? */
43 scm_fill_input (port
);
44 SCM to
= scm_ftell (port
);
45 ps
->nchars
= scm_to_int (to
) - scm_to_int (from
);
48 /* Read expression from port. */
49 if (!SCM_EOF_OBJECT_P (form
))
53 static SCM module
= SCM_BOOL_F
;
54 if (module
== SCM_BOOL_F
)
56 SCM function
= ly_lily_module_constant ("make-safe-lilypond-module");
57 module
= scm_call_0 (function
);
59 answer
= scm_eval (form
, module
);
62 answer
= scm_primitive_eval (form
);
65 /* Don't close the port here; if we re-enter this function via a
66 continuation, then the next time we enter it, we'll get an error.
67 It's a string port anyway, so there's no advantage to closing it
69 // scm_close_port (port);
75 catch_protected_parse_body (void *p
)
77 Parse_start
*ps
= (Parse_start
*) p
;
79 return internal_ly_parse_scm (ps
);
83 parse_handler (void *data
, SCM tag
, SCM args
)
85 Parse_start
*ps
= (Parse_start
*) data
;
87 ps
->start_location_
.error (_ ("GUILE signaled an error for the expression beginning here"));
89 if (scm_ilength (args
) > 2)
90 scm_display_error_message (scm_cadr (args
), scm_caddr (args
), scm_current_error_port ());
92 if (tag
== ly_symbol2scm ("read-error"))
99 protected_ly_parse_scm (Parse_start
*ps
)
102 Catch #t : catch all Scheme level errors.
104 return scm_internal_catch (SCM_BOOL_T
,
105 &catch_protected_parse_body
,
107 &parse_handler
, (void *) ps
);
110 bool parse_protect_global
= true;
111 bool parsed_objects_should_be_dead
= false;
113 /* Try parsing. Upon failure return SCM_UNDEFINED.
114 FIXME: shouldn't we return SCM_UNSCPECIFIED -- jcn */
116 ly_parse_scm (char const *s
, int *n
, Input i
, bool safe
)
120 ps
.start_location_
= i
;
123 SCM ans
= parse_protect_global
? protected_ly_parse_scm (&ps
)
124 : internal_ly_parse_scm (&ps
);