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Diff for /mandoc/Attic/mdoc.3 between version 1.1 and 1.52

version 1.1, 2009/01/16 14:04:26 version 1.52, 2011/01/01 12:18:37
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 .\"  .\"     $Id$
   .\"
   .\" Copyright (c) 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>
   .\" Copyright (c) 2010 Ingo Schwarze <schwarze@openbsd.org>
   .\"
   .\" Permission to use, copy, modify, and distribute this software for any
   .\" purpose with or without fee is hereby granted, provided that the above
   .\" copyright notice and this permission notice appear in all copies.
   .\"
   .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   .\"
 .Dd $Mdocdate$  .Dd $Mdocdate$
 .Dt mdoc 3  .Dt MDOC 3
 .Os  .Os
 .\"  
 .Sh NAME  .Sh NAME
   .Nm mdoc ,
 .Nm mdoc_alloc ,  .Nm mdoc_alloc ,
 .Nm mdoc_parseln ,  
 .Nm mdoc_endparse ,  .Nm mdoc_endparse ,
 .Nm mdoc_result ,  .Nm mdoc_free ,
 .Nm mdoc_free  .Nm mdoc_meta ,
 .Nd mdoc macro compiler  .Nm mdoc_node ,
 .\"  .Nm mdoc_parseln ,
   .Nm mdoc_reset
   .Nd mdoc macro compiler library
 .Sh SYNOPSIS  .Sh SYNOPSIS
   .In mandoc.h
 .In mdoc.h  .In mdoc.h
   .Vt extern const char * const * mdoc_macronames;
   .Vt extern const char * const * mdoc_argnames;
   .Ft int
   .Fo mdoc_addspan
   .Fa "struct mdoc *mdoc"
   .Fa "const struct tbl_span *span"
   .Fc
 .Ft "struct mdoc *"  .Ft "struct mdoc *"
 .Fn mdoc_alloc "void *data" "const struct mdoc_cb *cb"  .Fo mdoc_alloc
 .Ft void  .Fa "struct regset *regs"
 .Fn mdoc_free "struct mdoc *"  .Fa "void *data"
   .Fa "mandocmsg msgs"
   .Fc
 .Ft int  .Ft int
 .Fn mdoc_parseln "struct mdoc *" "int" "char *buf"  .Fn mdoc_endparse "struct mdoc *mdoc"
   .Ft void
   .Fn mdoc_free "struct mdoc *mdoc"
   .Ft "const struct mdoc_meta *"
   .Fn mdoc_meta "const struct mdoc *mdoc"
 .Ft "const struct mdoc_node *"  .Ft "const struct mdoc_node *"
 .Fn mdoc_result "struct mdoc *"  .Fn mdoc_node "const struct mdoc *mdoc"
 .Ft int  .Ft int
 .Fn mdoc_endparse "struct mdoc *"  .Fo mdoc_parseln
 .\"  .Fa "struct mdoc *mdoc"
   .Fa "int line"
   .Fa "char *buf"
   .Fc
   .Ft int
   .Fn mdoc_reset "struct mdoc *mdoc"
 .Sh DESCRIPTION  .Sh DESCRIPTION
 The  The
 .Nm mdoc  .Nm mdoc
 library parses lines of mdoc-macro text into an abstract syntax tree.  library parses lines of
   .Xr mdoc 7
   input
   into an abstract syntax tree (AST).
   .Pp
 In general, applications initiate a parsing sequence with  In general, applications initiate a parsing sequence with
 .Fn mdoc_alloc ,  .Fn mdoc_alloc ,
 parse each line in a document with  parse each line in a document with
 .Fn mdoc_parseln ,  .Fn mdoc_parseln ,
 close the parsing session with  close the parsing session with
 .Fn mdoc_endparse ,  .Fn mdoc_endparse ,
 operate over the syntax tree returned by  operate over the syntax tree returned by
 .Fn mdoc_result ,  .Fn mdoc_node
   and
   .Fn mdoc_meta ,
 then free all allocated memory with  then free all allocated memory with
 .Fn mdoc_free .  .Fn mdoc_free .
 See the  The
 .Sx EXAMPLES  .Fn mdoc_reset
 section for a full example.  function may be used in order to reset the parser for another input
 .\" The following requests should be uncommented and used where appropriate.  sequence.
 .\" This next request is for sections 2, 3, and 9 function return values only.  .Ss Types
 .\" .Sh RETURN VALUES  .Bl -ohang
 .\" .Sh EXAMPLES  .It Vt struct mdoc
 .\" The next request is for sections 2, 3, and 9 error and signal handling only.  An opaque type.
 .\" .Sh ERRORS  Its values are only used privately within the library.
 .\" .Sh SEE ALSO  .It Vt struct mdoc_node
 .\" .Xr foobar 1  A parsed node.
 .\" .Sh STANDARDS  See
 .\" .Sh HISTORY  .Sx Abstract Syntax Tree
 .\" .Sh AUTHORS  for details.
 .\" .Sh CAVEATS  .El
 .\" .Sh BUGS  .Ss Functions
   .Bl -ohang
   .It Fn mdoc_addspan
   Add a table span to the parsing stream.
   Returns 0 on failure, 1 on success.
   .It Fn mdoc_alloc
   Allocates a parsing structure.
   The
   .Fa data
   pointer is passed to
   .Fa msgs .
   Returns NULL on failure.
   If non-NULL, the pointer must be freed with
   .Fn mdoc_free .
   .It Fn mdoc_reset
   Reset the parser for another parse routine.
   After its use,
   .Fn mdoc_parseln
   behaves as if invoked for the first time.
   If it returns 0, memory could not be allocated.
   .It Fn mdoc_free
   Free all resources of a parser.
   The pointer is no longer valid after invocation.
   .It Fn mdoc_parseln
   Parse a nil-terminated line of input.
   This line should not contain the trailing newline.
   Returns 0 on failure, 1 on success.
   The input buffer
   .Fa buf
   is modified by this function.
   .It Fn mdoc_endparse
   Signals that the parse is complete.
   Note that if
   .Fn mdoc_endparse
   is called subsequent to
   .Fn mdoc_node ,
   the resulting tree is incomplete.
   Returns 0 on failure, 1 on success.
   .It Fn mdoc_node
   Returns the first node of the parse.
   Note that if
   .Fn mdoc_parseln
   or
   .Fn mdoc_endparse
   return 0, the tree will be incomplete.
   .It Fn mdoc_meta
   Returns the document's parsed meta-data.
   If this information has not yet been supplied or
   .Fn mdoc_parseln
   or
   .Fn mdoc_endparse
   return 0, the data will be incomplete.
   .El
   .Ss Variables
   .Bl -ohang
   .It Va mdoc_macronames
   An array of string-ified token names.
   .It Va mdoc_argnames
   An array of string-ified token argument names.
   .El
   .Ss Abstract Syntax Tree
   The
   .Nm
   functions produce an abstract syntax tree (AST) describing input in a
   regular form.
   It may be reviewed at any time with
   .Fn mdoc_nodes ;
   however, if called before
   .Fn mdoc_endparse ,
   or after
   .Fn mdoc_endparse
   or
   .Fn mdoc_parseln
   fail, it may be incomplete.
   .Pp
   This AST is governed by the ontological
   rules dictated in
   .Xr mdoc 7
   and derives its terminology accordingly.
   .Qq In-line
   elements described in
   .Xr mdoc 7
   are described simply as
   .Qq elements .
   .Pp
   The AST is composed of
   .Vt struct mdoc_node
   nodes with block, head, body, element, root and text types as declared
   by the
   .Va type
   field.
   Each node also provides its parse point (the
   .Va line ,
   .Va sec ,
   and
   .Va pos
   fields), its position in the tree (the
   .Va parent ,
   .Va child ,
   .Va nchild ,
   .Va next
   and
   .Va prev
   fields) and some type-specific data, in particular, for nodes generated
   from macros, the generating macro in the
   .Va tok
   field.
   .Pp
   The tree itself is arranged according to the following normal form,
   where capitalised non-terminals represent nodes.
   .Pp
   .Bl -tag -width "ELEMENTXX" -compact
   .It ROOT
   \(<- mnode+
   .It mnode
   \(<- BLOCK | ELEMENT | TEXT
   .It BLOCK
   \(<- HEAD [TEXT] (BODY [TEXT])+ [TAIL [TEXT]]
   .It ELEMENT
   \(<- TEXT*
   .It HEAD
   \(<- mnode*
   .It BODY
   \(<- mnode* [ENDBODY mnode*]
   .It TAIL
   \(<- mnode*
   .It TEXT
   \(<- [[:printable:],0x1e]*
   .El
   .Pp
   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
   .Sq \&.Bd \-literal ,
   an empty line will produce a zero-length string.
   Multiple body parts are only found in invocations of
   .Sq \&Bl \-column ,
   where a new body introduces a new phrase.
   .Ss Badly-nested Blocks
   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
   .Va end
   field, is of the BODY
   .Va type ,
   has the same
   .Va tok
   as the BLOCK it is ending, and has a
   .Va 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.
   .Pp
   An ENDBODY node is generated when a block ends while one of its child
   blocks is still open, like in the following example:
   .Bd -literal -offset indent
   \&.Ao ao
   \&.Bo bo ac
   \&.Ac bc
   \&.Bc end
   .Ed
   .Pp
   This example results in the following block structure:
   .Bd -literal -offset indent
   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
   .Ed
   .Pp
   Here, the formatting of the
   .Sq \&Ao
   block extends from TEXT ao to TEXT ac,
   while the formatting of the
   .Sq \&Bo
   block extends from TEXT bo to TEXT bc.
   It renders as follows in
   .Fl T Ns Cm ascii
   mode:
   .Pp
   .Dl <ao [bo ac> bc] end
   .Pp
   Support for badly-nested blocks is only provided for backward
   compatibility with some older
   .Xr mdoc 7
   implementations.
   Using badly-nested blocks is
   .Em strongly discouraged :
   the
   .Fl T Ns Cm html
   and
   .Fl T Ns Cm xhtml
   front-ends 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.
   .Sh EXAMPLES
   The following example reads lines from stdin and parses them, operating
   on the finished parse tree with
   .Fn parsed .
   This example does not error-check nor free memory upon failure.
   .Bd -literal -offset indent
   struct regset regs;
   struct mdoc *mdoc;
   const struct mdoc_node *node;
   char *buf;
   size_t len;
   int line;
   
   bzero(&regs, sizeof(struct regset));
   line = 1;
   mdoc = mdoc_alloc(&regs, NULL, NULL);
   buf = NULL;
   alloc_len = 0;
   
   while ((len = getline(&buf, &alloc_len, stdin)) >= 0) {
       if (len && buflen[len - 1] = '\en')
           buf[len - 1] = '\e0';
       if ( ! mdoc_parseln(mdoc, line, buf))
           errx(1, "mdoc_parseln");
       line++;
   }
   
   if ( ! mdoc_endparse(mdoc))
       errx(1, "mdoc_endparse");
   if (NULL == (node = mdoc_node(mdoc)))
       errx(1, "mdoc_node");
   
   parsed(mdoc, node);
   mdoc_free(mdoc);
   .Ed
   .Pp
   To compile this, execute
   .Pp
   .Dl % cc main.c libmdoc.a libmandoc.a
   .Pp
   where
   .Pa main.c
   is the example file.
   .Sh SEE ALSO
   .Xr mandoc 1 ,
   .Xr mdoc 7
   .Sh AUTHORS
   The
   .Nm
   library was written by
   .An Kristaps Dzonsons Aq kristaps@bsd.lv .
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