Support for badly nested blocks, written around the time of

[mandoc.git] / mdoc.3

diff --git a/mdoc.3 b/mdoc.3
index 8dd79ffd3bd674710e0cd7a79403b79bbde9650b..f65b4c39e35fc17e6b56c60cea8fcceca60bed31 100644 (file)
--- a/mdoc.3
+++ b/mdoc.3
@@ -1,192 +1,365 @@
-.\" 
-.Dd $Mdocdate: January 20 2009 $
-.Dt mdoc 3
-.Os
+.\"    $Id: mdoc.3,v 1.45 2010/06/29 19:20:38 schwarze Exp $
+.\"
+.\" Copyright (c) 2009-2010 Kristaps Dzonsons <kristaps@bsd.lv>
+.\"
+.\" 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: June 29 2010 $
+.Dt MDOC 3
+.Os

 .Sh NAME
 .Sh NAME

+.Nm mdoc ,

 .Nm mdoc_alloc ,
 .Nm mdoc_alloc ,

-.Nm mdoc_parseln ,

 .Nm mdoc_endparse ,
 .Nm mdoc_endparse ,

-.Nm mdoc_node ,
+.Nm mdoc_free ,

 .Nm mdoc_meta ,
 .Nm mdoc_meta ,

-.Nm mdoc_free
+.Nm mdoc_node ,
+.Nm mdoc_parseln ,
+.Nm mdoc_reset

 .Nd mdoc macro compiler library
 .Nd mdoc macro compiler library

-.\"

 .Sh SYNOPSIS
 .Sh SYNOPSIS

-.Fd #include <mdoc.h>
+.In mandoc.h
+.In regs.h
+.In mdoc.h

 .Vt extern const char * const * mdoc_macronames;
 .Vt extern const char * const * mdoc_argnames;
 .Ft "struct mdoc *"
 .Vt extern const char * const * mdoc_macronames;
 .Vt extern const char * const * mdoc_argnames;
 .Ft "struct mdoc *"

-.Fn mdoc_alloc "void *data" "const struct mdoc_cb *cb"
+.Fo mdoc_alloc
+.Fa "struct regset *regs"
+.Fa "void *data"
+.Fa "int pflags"
+.Fa "mandocmsg msgs"
+.Fc
+.Ft int
+.Fn mdoc_endparse "struct mdoc *mdoc"

 .Ft void
 .Fn mdoc_free "struct mdoc *mdoc"
 .Ft void
 .Fn mdoc_free "struct mdoc *mdoc"

-.Ft int
-.Fn mdoc_parseln "struct mdoc *mdoc" "int line" "char *buf"
-.Ft "const struct mdoc_node *"
-.Fn mdoc_node "struct mdoc *mdoc"

 .Ft "const struct mdoc_meta *"
 .Ft "const struct mdoc_meta *"

-.Fn mdoc_meta "struct mdoc *mdoc"
+.Fn mdoc_meta "const struct mdoc *mdoc"
+.Ft "const struct mdoc_node *"
+.Fn mdoc_node "const struct mdoc *mdoc"

 .Ft int
 .Ft int

-.Fn mdoc_endparse "struct mdoc *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
 The
 .Nm mdoc
 .Sh DESCRIPTION
 The
 .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
 .Fn mdoc_alloc ,
 In general, applications initiate a parsing sequence with
 .Fn mdoc_alloc ,

-parse each line in a document with 
+parse each line in a document with

 .Fn mdoc_parseln ,
 close the parsing session with
 .Fn mdoc_endparse ,
 operate over the syntax tree returned by
 .Fn mdoc_parseln ,
 close the parsing session with
 .Fn mdoc_endparse ,
 operate over the syntax tree returned by

-.Fn mdoc_node 
+.Fn mdoc_node

 and
 .Fn mdoc_meta ,
 then free all allocated memory with
 .Fn mdoc_free .
 and
 .Fn mdoc_meta ,
 then free all allocated memory with
 .Fn mdoc_free .

+The
+.Fn mdoc_reset
+function may be used in order to reset the parser for another input
+sequence.

 See the
 .Sx EXAMPLES
 See the
 .Sx EXAMPLES

-section for a full example.
+section for a simple example.

 .Pp
 .Pp

-.\" Function descriptions.
+This section further defines the
+.Sx Types ,
+.Sx Functions
+and
+.Sx Variables
+available to programmers.
+Following that, the
+.Sx Abstract Syntax Tree
+section documents the output tree.
+.Ss Types
+Both functions (see
+.Sx Functions )
+and variables (see
+.Sx Variables )
+may use the following types:
+.Bl -ohang
+.It Vt struct mdoc
+An opaque type defined in
+.Pa mdoc.c .
+Its values are only used privately within the library.
+.It Vt struct mdoc_node
+A parsed node.
+Defined in
+.Pa mdoc.h .
+See
+.Sx Abstract Syntax Tree
+for details.
+.It Vt mandocmsg
+A function callback type defined in
+.Pa mandoc.h .
+.El
+.Ss Functions

 Function descriptions follow:
 Function descriptions follow:

-.Bl -ohang -offset indent
+.Bl -ohang

 .It Fn mdoc_alloc
 .It Fn mdoc_alloc

-Allocates a parsing structure.  The
+Allocates a parsing structure.
+The

 .Fa data
 .Fa data

-pointer is passed to callbacks in
-.Fa cb , 
-which are documented further in the header file.  Returns NULL on
-failure.  If non-NULL, the pointer must be freed with
+pointer is passed to
+.Fa msgs .
+The
+.Fa pflags
+arguments are defined in
+.Pa mdoc.h .
+Returns NULL on failure.
+If non-NULL, the pointer must be freed with

 .Fn mdoc_free .
 .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
 .It Fn mdoc_free

-Free all resources of a parser.  The pointer is no longer valid after
-invocation.
+Free all resources of a parser.
+The pointer is no longer valid after invocation.

 .It Fn mdoc_parseln
 .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 
+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
 .Fa buf
 is modified by this function.
 .It Fn mdoc_endparse

-Signals that the parse is complete.  Note that if 
+Signals that the parse is complete.
+Note that if

 .Fn mdoc_endparse
 is called subsequent to
 .Fn mdoc_node ,
 .Fn mdoc_endparse
 is called subsequent to
 .Fn mdoc_node ,

-the resulting tree is incomplete.  Returns 0 on failure, 1 on success.
+the resulting tree is incomplete.
+Returns 0 on failure, 1 on success.

 .It Fn mdoc_node
 .It Fn mdoc_node

-Returns the first node of the parse.  Note that if 
+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
 .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 
+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
 .Fn mdoc_parseln
 or
 .Fn mdoc_endparse
 return 0, the data will be incomplete.
 .El

-.Pp
-.\" Variable descriptions.
+.Ss Variables

 The following variables are also defined:
 The following variables are also defined:

-.Bl -ohang -offset indent
+.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
 .It Va mdoc_macronames
 An array of string-ified token names.
 .It Va mdoc_argnames
 An array of string-ified token argument names.
 .El

-.Pp
+.Ss Abstract Syntax Tree
+The

 .Nm
 .Nm

-is
-.Ud
-.\" 
+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
+A special kind of node is available to end the formatting
+associated with a given block before the physical end of that block.
+Such an ENDBODY node 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 Ao block extends from TEXT ao to TEXT ac,
+while the formatting of the Bo block extends from TEXT bo to TEXT bc,
+rendering like this in
+.Fl T Ns Cm ascii
+mode:
+.Dl <ao [bo ac> bc] end
+Support for badly nested blocks is only provided for backward
+compatibility with some older
+.Xr mdoc 7
+implementations.
+Using them in new code is stronly discouraged:
+Some frontends, in particular
+.Fl T Ns Cm html ,
+are unable to render them in any meaningful way,
+many other
+.Xr mdoc 7
+implementations do not support them, and even for those that do,
+the behaviour is not well-defined, in particular when using multiple
+levels of badly nested blocks.

 .Sh EXAMPLES
 The following example reads lines from stdin and parses them, operating
 .Sh EXAMPLES
 The following example reads lines from stdin and parses them, operating

-on the finished parse tree with 
+on the finished parse tree with

 .Fn parsed .
 .Fn parsed .

-Note that, if the last line of the file isn't newline-terminated, this
-will truncate the file's last character (see 
-.Xr fgetln 3 ) .
-Further, this example does not error-check nor free memory upon failure.
-.Bd -literal
+This example does not error-check nor free memory upon failure.
+.Bd -literal -offset indent
+struct regset regs;

 struct mdoc *mdoc;
 struct mdoc *mdoc;

-struct mdoc_node *node;
+const struct mdoc_node *node;

 char *buf;
 size_t len;
 int line;
 
 char *buf;
 size_t len;
 int line;
 

+bzero(&regs, sizeof(struct regset));

 line = 1;
 line = 1;

-mdoc = mdoc_alloc(NULL, NULL);
+mdoc = mdoc_alloc(&regs, NULL, 0, NULL);
+buf = NULL;
+alloc_len = 0;

 
 

-while ((buf = fgetln(fp, &len))) {
-       buf[len - 1] = '\\0';
-       if ( ! mdoc_parseln(mdoc, line, buf))
-               errx(1, "mdoc_parseln");
-       line++;
+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))
 }
 
 if ( ! mdoc_endparse(mdoc))

-       errx(1, "mdoc_endparse");
+    errx(1, "mdoc_endparse");

 if (NULL == (node = mdoc_node(mdoc)))
 if (NULL == (node = mdoc_node(mdoc)))

-       errx(1, "mdoc_node");
+    errx(1, "mdoc_node");

 
 parsed(mdoc, node);
 mdoc_free(mdoc);
 .Ed
 
 parsed(mdoc, node);
 mdoc_free(mdoc);
 .Ed

-.\"
+.Pp
+Please see
+.Pa main.c
+in the source archive for a rigorous reference.

 .Sh SEE ALSO
 .Sh SEE ALSO

-.Xr mdoc 7 ,
-.Xr mdoc.samples 7 ,
-.Xr groff 1 ,
-.Xr mdocml 1
-.\"
-.\"
+.Xr mandoc 1 ,
+.Xr mdoc 7

 .Sh AUTHORS
 The
 .Nm
 .Sh AUTHORS
 The
 .Nm

-utility was written by 
-.An Kristaps Dzonsons Aq kristaps@kth.se .
-.\"
-.\"
-.Sh BUGS
-Bugs, un-implemented macros and incompabilities are documented in this
-section.  The baseline for determining whether macro parsing is 
-.Qq incompatible
-is the default
-.Xr groff 1
-system bundled with 
-.Ox .
-.Pp
-Un-implemented: the 
-.Sq \&Xc
-and
-.Sq \&Xo
-macros aren't handled when used to span lines for the
-.Sq \&It
-macro.  Such usage is specifically discouraged in
-.Xr mdoc.samples 7 .
-.Pp
-Bugs: when 
-.Sq \&It \-column
-is invoked, whitespace is not stripped around
-.Sq \&Ta
-or tab-character separators.
-.Pp
-Incompatible: the 
-.Sq \&At
-macro only accepts a single parameter.  Furthermore, several macros 
-.Pf ( Sq \&Pp ,
-.Sq \&It ,
-and possibly others) accept multiple arguments with a warning.
-.Pp
-Incompatible: only those macros specified by
-.Xr mdoc.samples 7
-and
-.Xr mdoc 7
-for
-.Ox
-are supported; support for
-.Nx
-and other BSD systems is in progress.
+library was written by
+.An Kristaps Dzonsons Aq kristaps@bsd.lv .