NAME
mandoc,
deroff,
mandocmsg,
man_mparse,
man_validate,
mdoc_validate,
mparse_alloc,
mparse_free,
mparse_getkeep,
mparse_keep,
mparse_open,
mparse_readfd,
mparse_reset,
mparse_result,
mparse_strerror,
mparse_strlevel,
mparse_updaterc —
mandoc macro compiler library
SYNOPSIS
#include <sys/types.h>
#include <mandoc.h>
#define ASCII_NBRSP
#define ASCII_HYPH
#define ASCII_BREAK
struct mparse *
mparse_alloc(
int options,
enum mandoclevel wlevel,
mandocmsg
mmsg,
char *defos);
void
(*mandocmsg)(
enum mandocerr errtype,
enum mandoclevel level,
const char
*file,
int line,
int col,
const char *msg);
void
mparse_free(
struct mparse *parse);
const char *
mparse_getkeep(
const struct mparse
*parse);
void
mparse_keep(
struct mparse *parse);
int
mparse_open(
struct mparse *parse,
const char *fname);
enum mandoclevel
mparse_readfd(
struct mparse *parse,
int fd,
const char *fname);
void
mparse_reset(
struct mparse *parse);
void
mparse_result(
struct mparse *parse,
struct roff_man **man,
char
**sodest);
const char *
mparse_strerror(
enum mandocerr);
const char *
mparse_strlevel(
enum mandoclevel);
void
mparse_updaterc(
struct mparse *parse,
enum mandoclevel *rc);
#include <roff.h>
void
deroff(
char **dest,
const struct roff_node *node);
#include <sys/types.h>
#include <mandoc.h>
#include <mdoc.h>
extern const char * const * mdoc_argnames;
extern const char * const * mdoc_macronames;
void
mdoc_validate(
struct roff_man *mdoc);
#include <sys/types.h>
#include <mandoc.h>
#include <man.h>
extern const char * const * man_macronames;
const struct mparse *
man_mparse(
const struct roff_man *man);
void
man_validate(
struct roff_man *man);
DESCRIPTION
The
mandoc library parses a
UNIX
manual into an abstract syntax tree (AST).
UNIX
manuals are composed of
mdoc(7) or
man(7), and may be mixed with
roff(7),
tbl(7), and
eqn(7) invocations.
The following describes a general parse sequence:
- initiate a parsing sequence with
mchars_alloc(3) and
mparse_alloc();
- open a file with
open(2) or
mparse_open();
- parse it with mparse_readfd();
- close it with
close(2);
- retrieve the syntax tree with
mparse_result();
- depending on whether the macroset
member of the returned struct roff_man is
MACROSET_MDOC
or
MACROSET_MAN
, validate it with
mdoc_validate() or man_validate(),
respectively;
- if information about the validity of the input is needed,
fetch it with mparse_updaterc();
- iterate over parse nodes with starting from the
first member of the returned struct
roff_man;
- free all allocated memory with
mparse_free() and
mchars_free(3), or
invoke mparse_reset() and go back to step 2 to parse new
files.
REFERENCE
This section documents the functions, types, and variables available via
<mandoc.h>, with the exception of
those documented in
mandoc_escape(3) and
mchars_alloc(3).
Types
- enum mandocerr
- An error or warning message during parsing.
- enum mandoclevel
- A classification of an enum
mandocerr as regards system operation. See the DIAGNOSTICS section
in mandoc(1) regarding the
meanings of the levels.
- struct mparse
- An opaque pointer to a running parse sequence. Created
with mparse_alloc() and freed with
mparse_free(). This may be used across parsed input if
mparse_reset() is called between parses.
- mandocmsg
- A prototype for a function to handle error and warning
messages emitted by the parser.
Functions
- deroff()
- Obtain a text-only representation of a
struct roff_node, including text contained in its
child nodes. To be used on children of the first
member of struct roff_man. When it is no longer
needed, the pointer returned from deroff() can be passed
to free(3).
- man_mparse()
- Get the parser used for the current output. Declared in
<man.h>, implemented in
man.c.
- man_validate()
- Validate the
MACROSET_MAN
parse
tree obtained with mparse_result(). Declared in
<man.h>, implemented in
man.c.
- mdoc_validate()
- Validate the
MACROSET_MDOC
parse
tree obtained with mparse_result(). Declared in
<mdoc.h>, implemented in
mdoc.c.
- mparse_alloc()
- Allocate a parser. The arguments have the following
effect:
-
-
- options
- When the
MPARSE_MDOC
or
MPARSE_MAN
bit is set, only that parser is
used. Otherwise, the document type is automatically detected.
When the MPARSE_SO
bit is set,
roff(7)
so file inclusion requests are always honoured.
Otherwise, if the request is the only content in an input file, only
the file name is remembered, to be returned in the
sodest argument of
mparse_result().
When the MPARSE_QUICK
bit is set, parsing is
aborted after the NAME section. This is for example useful in
makewhatis(8)
-Q to quickly build minimal databases.
-
-
- wlevel
- Can be set to
MANDOCLEVEL_BADARG
,
MANDOCLEVEL_ERROR
, or
MANDOCLEVEL_WARNING
. Messages below the
selected level will be suppressed.
-
-
- mmsg
- A callback function to handle errors and warnings. See
main.c for an example. If printing of error messages
is not desired,
NULL
may be passed.
-
-
- defos
- A default string for the
mdoc(7) ‘Os’
macro, overriding the
OSNAME
preprocessor
definition and the results of
uname(3). Passing
NULL
sets no default.
The same parser may be used for multiple files so long as
mparse_reset() is called between parses.
mparse_free() must be called to free the memory
allocated by this function. Declared in
<mandoc.h>, implemented in
read.c.
- mparse_free()
- Free all memory allocated by
mparse_alloc(). Declared in
<mandoc.h>, implemented in
read.c.
- mparse_getkeep()
- Acquire the keep buffer. Must follow a call of
mparse_keep(). Declared in
<mandoc.h>, implemented in
read.c.
- mparse_keep()
- Instruct the parser to retain a copy of its parsed input.
This can be acquired with subsequent mparse_getkeep()
calls. Declared in <mandoc.h>,
implemented in read.c.
- mparse_open()
- Open the file for reading. If that fails and
fname does not already end in
‘
.gz
’, try again after appending
‘.gz
’. Save the information whether
the file is zipped or not. Return a file descriptor open for reading or -1
on failure. It can be passed to mparse_readfd() or used
directly. Declared in
<mandoc.h>, implemented in
read.c.
- mparse_readfd()
- Parse a file descriptor opened with
open(2) or
mparse_open(). Pass the associated filename in
fname. This function may be called multiple times
with different parameters; however,
close(2) and
mparse_reset() should be invoked between parses.
Declared in <mandoc.h>,
implemented in read.c.
- mparse_reset()
- Reset a parser so that mparse_readfd()
may be used again. Declared in
<mandoc.h>, implemented in
read.c.
- mparse_result()
- Obtain the result of a parse. One of the two pointers
will be filled in. Declared in
<mandoc.h>, implemented in
read.c.
- mparse_strerror()
- Return a statically-allocated string representation of an
error code. Declared in
<mandoc.h>, implemented in
read.c.
- mparse_strlevel()
- Return a statically-allocated string representation of a
level code. Declared in
<mandoc.h>, implemented in
read.c.
- mparse_updaterc()
- If the highest warning or error level that occurred
during the current parse is higher than
*rc, update *rc accordingly.
This is useful after calling mdoc_validate() or
man_validate(). Declared in
<mandoc.h>, implemented in
read.c.
Variables
- man_macronames
- The string representation of a
man(7) macro as indexed by
enum mant.
- mdoc_argnames
- The string representation of an
mdoc(7) macro argument as
indexed by enum mdocargt.
- mdoc_macronames
- The string representation of an
mdoc(7) macro as indexed by
enum mdoct.
IMPLEMENTATION NOTES
This section consists of structural documentation for
mdoc(7) and
man(7) syntax trees and strings.
Man and Mdoc Strings
Strings may be extracted from mdoc and man meta-data, or from text nodes
(MDOC_TEXT and MAN_TEXT, respectively). These strings have special
non-printing formatting cues embedded in the text itself, as well as
roff(7) escapes preserved from
input. Implementing systems will need to handle both situations to produce
human-readable text. In general, strings may be assumed to consist of 7-bit
ASCII characters.
The following non-printing characters may be embedded in text strings:
-
-
ASCII_NBRSP
- A non-breaking space character.
-
-
ASCII_HYPH
- A soft hyphen.
-
-
ASCII_BREAK
- A breakable zero-width space.
Escape characters are also passed verbatim into text strings. An escape
character is a sequence of characters beginning with the backslash
(‘\’). To construct human-readable text, these should be
intercepted with
mandoc_escape(3) and
converted with one the functions described in
mchars_alloc(3).
Man Abstract Syntax Tree
This AST is governed by the ontological rules dictated in
man(7) and derives its terminology
accordingly.
The AST is composed of
struct roff_node nodes with
element, root and text types as declared by the
type
field. Each node also provides its parse point (the
line,
pos, and
sec fields), its position in the tree (the
parent,
child,
next and
prev fields) and some
type-specific data.
The tree itself is arranged according to the following normal form, where
capitalised non-terminals represent nodes.
- ROOT
- ← mnode+
- mnode
- ← ELEMENT | TEXT | BLOCK
- BLOCK
- ← HEAD BODY
- HEAD
- ← mnode*
- BODY
- ← mnode*
- ELEMENT
- ← ELEMENT | TEXT*
- TEXT
- ← [[:ascii:]]*
The only elements capable of nesting other elements are those with next-line
scope as documented in
man(7).
Mdoc Abstract Syntax Tree
This AST is governed by the ontological rules dictated in
mdoc(7) and derives its
terminology accordingly. “In-line” elements described in
mdoc(7) are described simply as
“elements”.
The AST is composed of
struct roff_node nodes with block,
head, body, element, root and text types as declared by the
type field. Each node also provides its parse point (the
line,
pos, and
sec fields), its position in the tree (the
parent,
child,
last,
next and
prev fields) and some type-specific data, in particular,
for nodes generated from macros, the generating macro in the
tok field.
The tree itself is arranged according to the following normal form, where
capitalised non-terminals represent nodes.
- ROOT
- ← mnode+
- mnode
- ← BLOCK | ELEMENT | TEXT
- BLOCK
- ← HEAD [TEXT] (BODY [TEXT])+ [TAIL [TEXT]]
- ELEMENT
- ← TEXT*
- HEAD
- ← mnode*
- BODY
- ← mnode* [ENDBODY mnode*]
- TAIL
- ← mnode*
- TEXT
- ← [[:ascii:]]*
Of note are the TEXT nodes following the HEAD, BODY and TAIL nodes of the BLOCK
production: these refer to punctuation marks. Furthermore, although a TEXT
node will generally have a non-zero-length string, in the specific case of
‘.Bd -literal’, an empty line will produce a zero-length string.
Multiple body parts are only found in invocations of ‘Bl -column’,
where a new body introduces a new phrase.
The
mdoc(7) syntax tree accommodates
for broken block structures as well. The ENDBODY node is available to end the
formatting associated with a given block before the physical end of that
block. It has a non-null
end field, is of the BODY
type, has the same
tok as the
BLOCK it is ending, and has a
pending field pointing to
that BLOCK's BODY node. It is an indirect child of that BODY node and has no
children of its own.
An ENDBODY node is generated when a block ends while one of its child blocks is
still open, like in the following example:
.Ao ao
.Bo bo ac
.Ac bc
.Bc end
This example results in the following block structure:
BLOCK Ao
HEAD Ao
BODY Ao
TEXT ao
BLOCK Bo, pending -> Ao
HEAD Bo
BODY Bo
TEXT bo
TEXT ac
ENDBODY Ao, pending -> Ao
TEXT bc
TEXT end
Here, the formatting of the ‘Ao’ block extends from TEXT ao to TEXT
ac, while the formatting of the ‘Bo’ block extends from TEXT bo to
TEXT bc. It renders as follows in
-Tascii
mode:
<ao [bo ac> bc] end
Support for badly-nested blocks is only provided for backward compatibility with
some older
mdoc(7)
implementations. Using badly-nested blocks is
strongly
discouraged; for example, the
-Thtml
and
-Txhtml front-ends to
mandoc(1) are unable to render
them in any meaningful way. Furthermore, behaviour when encountering
badly-nested blocks is not consistent across troff implementations, especially
when using multiple levels of badly-nested blocks.
SEE ALSO
mandoc(1),
man.cgi(3),
mandoc_escape(3),
mandoc_headers(3),
mandoc_malloc(3),
mansearch(3),
mchars_alloc(3),
tbl(3),
eqn(7),
man(7),
mandoc_char(7),
mdoc(7),
roff(7),
tbl(7)
AUTHORS
The
mandoc library was written by
Kristaps
Dzonsons
<
kristaps@bsd.lv> and is
maintained by
Ingo Schwarze
<
schwarze@openbsd.org>.