Provided by: libbtparse-dev_0.89-1_amd64 
NAME
bt_input - input/parsing functions in btparse library
SYNOPSIS
void bt_set_stringopts (bt_metatype_t metatype, btshort options);
AST * bt_parse_entry_s (char * entry_text,
char * filename,
int line,
btshort options,
boolean * status);
AST * bt_parse_entry (FILE * infile,
char * filename,
btshort options,
boolean * status);
AST * bt_parse_file (char * filename,
btshort options,
boolean * overall_status);
DESCRIPTION
The functions described here are used to read and parse BibTeX data, converting it from
raw text to abstract-syntax trees (ASTs).
bt_set_stringopts ()
void bt_set_stringopts (bt_metatype_t metatype, btshort options);
Set the string-processing options for a particular entry metatype. This affects the
entry post-processing done by "bt_parse_entry_s()", "bt_parse_entry()", and
"bt_parse_file()". If "bt_set_stringopts()" is never called, the four metatypes
default to the following sets of string options:
BTE_REGULAR BTO_CONVERT | BTO_EXPAND | BTO_PASTE | BTO_COLLAPSE
BTE_COMMENT 0
BTE_PREAMBLE 0
BTE_MACRODEF BTO_CONVERT | BTO_EXPAND | BTO_PASTE
For example,
bt_set_stringopts (BTE_COMMENT, BTO_COLLAPSE);
will cause the library to collapse whitespace in the value from all comment entries;
the AST returned by one of the "bt_parse_*" functions will reflect this change.
bt_parse_entry ()
AST * bt_parse_entry (FILE * infile,
char * filename,
btshort options,
boolean * status);
Scans and parses the next BibTeX entry in "infile". You should supply "filename" to
help btparse generate accurate error messages; the library keeps track of "infile"'s
current line number internally, so you don't need to pass that in. "options" should
be a bitmap of non-string-processing options (currently, "BTO_NOSTORE" to disable
storing macro expansions is the only such option). *status will be set to "TRUE" if
the entry parsed successfully or with only minor warnings, and "FALSE" if there were
any serious lexical or syntactic errors. If "status" is "NULL", then the parse status
will be unavailable to you. Both minor warnings and serious errors are reported on
"stderr".
Returns a pointer to the abstract-syntax tree (AST) describing the entry just parsed,
or "NULL" if no more entries were found in "infile" (this will leave "infile" at end-
of-file). Do not attempt to second guess "bt_parse_entry()" by detecting end-of-file
yourself; it must be allowed to determine this on its own so it can clean up some
static data that is preserved between calls on the same file.
"bt_parse_entry()" has two important restrictions that you should know about. First,
you should let btparse manage all the input on the file; this is for reasons both
superficial (so the library knows the current line number in order to generate
accurate error messages) and fundamental (the library must be allowed to detect end-
of-file in order to cleanup certain static variables and allow you to parse another
file). Second, you cannot interleave the parsing of two different files; attempting
to do so will result in a fatal error that will crash your program. This is a direct
result of the static state maintained between calls of "bt_parse_entry()".
Because of two distinct "failures" possible for "bt_parse_entry()" (end-of-file, which
is expected but means to stop processing the current file; and error-in-input, which
is not expected but allows you to continue processing the same file), you should
usually call it like this:
while (entry = bt_parse_entry (file, filename, options, &ok))
{
if (ok)
{
/* ... process entry ... */
}
}
At the end of this loop, "feof (file)" will be true.
bt_parse_entry_s ()
AST * bt_parse_entry_s (char * entry_text,
char * filename,
int line,
btshort options,
boolean * status)
Scans and parses a single complete BibTeX entry contained in a string, "entry_text".
If you read this string from a file, you should help btparse generate accurate error
messages by supplying the name of the file as "filename" and the line number of the
beginning of the entry as "line"; otherwise, set "filename" to "NULL" and "line" to 1.
"options" and "status" are the same as for "bt_parse_entry()".
Returns a pointer to the abstract-syntax tree (AST) describing the entry just parsed,
and "NULL" if no entries were found in "entry_text" or if "entry_text" was "NULL".
You should call "bt_parse_entry_s()" once more than the total number of entries you
wish to parse; on the final call, set "entry_text" to "NULL" so the function knows
there's no more text to parse. This final call allows it to clean up some structures
allocated on the first call. Thus, "bt_parse_entry_s()" is usually used like this:
char * entry_text;
btshort options = 0;
boolean ok;
AST * entry_ast;
while (entry_text = get_more_text ())
{
entry_ast = bt_parse_entry_s (entry_text, NULL, 1, options, &ok);
if (ok)
{
/* ... process entry ... */
}
}
bt_parse_entry_s (NULL, NULL, 1, options, NULL); /* cleanup */
assuming that "get_more_text()" returns a pointer to the text of an entry to parse, or
"NULL" if there's no more text available.
bt_parse_file ()
AST * bt_parse_file (char * filename,
btshort options,
boolean * status)
Scans and parses an entire BibTeX file. If "filename" is "NULL" or "-", then "stdin"
will be read; otherwise, attempts to open the named file. If this attempt fails,
prints an error message to "stderr" and returns "NULL". "options" and "status" are
the same as for "bt_parse_entry()"---note that *status will be "FALSE" if there were
any errors in the entire file; for finer granularity of error-checking, you should use
"bt_parse_entry()".
Returns a pointer to a linked list of ASTs representing the entries in the file, or
"NULL" if no entries were found in the file. This list can be traversed with
"bt_next_entry()", and the individual entries then traversed as usual (see
bt_traversal).
SEE ALSO
btparse, bt_postprocess, bt_traversal
AUTHOR
Greg Ward <gward@python.net>