Memory-corruption fix.

[mandoc.git] / mdoc.3

diff --git a/mdoc.3 b/mdoc.3
index 6da2382e788d9a00ea718313d84aa78e5b0e08b8..226895b9e9e09be03aaad48b46b36b1972af8e9f 100644 (file)
--- a/mdoc.3
+++ b/mdoc.3
@@ -1,8 +1,25 @@
+.\" $Id: mdoc.3,v 1.13 2009/02/27 09:14:02 kristaps Exp $
+.\"
+.\" Copyright (c) 2009 Kristaps Dzonsons <kristaps@kth.se>
+.\"
+.\" 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: January 19 2009 $
+.Dd $Mdocdate: February 27 2009 $

 .Dt mdoc 3
 .Os
 .Dt mdoc 3
 .Os

-.\"
+.\" SECTION

 .Sh NAME
 .Nm mdoc_alloc ,
 .Nm mdoc_parseln ,
 .Sh NAME
 .Nm mdoc_alloc ,
 .Nm mdoc_parseln ,


@@ -11,7 +28,7 @@
 .Nm mdoc_meta ,
 .Nm mdoc_free
 .Nd mdoc macro compiler library
 .Nm mdoc_meta ,
 .Nm mdoc_free
 .Nd mdoc macro compiler library

-.\"
+.\" SECTION

 .Sh SYNOPSIS
 .Fd #include <mdoc.h>
 .Vt extern const char * const * mdoc_macronames;
 .Sh SYNOPSIS
 .Fd #include <mdoc.h>
 .Vt extern const char * const * mdoc_macronames;


@@ -28,11 +45,31 @@
 .Fn mdoc_meta "struct mdoc *mdoc"
 .Ft int
 .Fn mdoc_endparse "struct mdoc *mdoc"
 .Fn mdoc_meta "struct mdoc *mdoc"
 .Ft int
 .Fn mdoc_endparse "struct mdoc *mdoc"

-.\"
+.\" SECTION

 .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 mdoc input into an abstract syntax tree.  
+.Dq mdoc ,
+which is used to format BSD manual pages, is a macro package of the
+.Dq roff
+language.  The
+.Nm
+library implements only those macros documented in the
+.Xr mdoc 7
+and
+.Xr mdoc.samples 7
+manuals.  Documents with 
+.Xr refer 1 ,
+.Xr eqn 1
+and other pre-processor sections aren't accomodated.
+.\" PARAGRAPH
+.Pp
+.Nm
+is
+.Ud
+.\" PARAGRAPH
+.Pp

 In general, applications initiate a parsing sequence with
 .Fn mdoc_alloc ,
 parse each line in a document with 
 In general, applications initiate a parsing sequence with
 .Fn mdoc_alloc ,
 parse each line in a document with 


@@ -48,10 +85,48 @@ then free all allocated memory with
 See the
 .Sx EXAMPLES
 section for a full example.
 See the
 .Sx EXAMPLES
 section for a full example.

+.\" PARAGRAPH

 .Pp
 .Pp

-.\" Function descriptions.
+This section further defines the 
+.Sx Types ,
+.Sx Functions 
+and
+.Sx Variables
+available to programmers.  Following that,
+.Sx Character Encoding
+describes input format.  Lastly, 
+.Sx Abstract Syntax Tree ,
+documents the output tree.
+.\" SUBSECTION
+.Ss Types
+Both functions (see
+.Sx Functions )
+and variables (see
+.Sx Variables )
+may use the following types:
+.Bl -ohang -offset "XXXX"
+.\" LIST-ITEM
+.It Vt struct mdoc
+An opaque type defined in
+.Pa mdoc.c .
+Its values are only used privately within the library.
+.\" LIST-ITEM
+.It Vt struct mdoc_cb
+A set of message callbacks defined in
+.Pa mdoc.h .
+.\" LIST-ITEM
+.It Vt struct mdoc_node
+A parsed node.  Defined in
+.Pa mdoc.h .
+See 
+.Sx Abstract Syntax Tree
+for details.
+.El
+.\" SUBSECTION
+.Ss Functions

 Function descriptions follow:
 Function descriptions follow:

-.Bl -ohang -offset indent
+.Bl -ohang -offset "XXXX"
+.\" LIST-ITEM

 .It Fn mdoc_alloc
 Allocates a parsing structure.  The
 .Fa data
 .It Fn mdoc_alloc
 Allocates a parsing structure.  The
 .Fa data


@@ -60,20 +135,24 @@ pointer is passed to callbacks in
 which are documented further in the header file.  Returns NULL on
 failure.  If non-NULL, the pointer must be freed with
 .Fn mdoc_free .
 which are documented further in the header file.  Returns NULL on
 failure.  If non-NULL, the pointer must be freed with
 .Fn mdoc_free .

+.\" LIST-ITEM

 .It Fn mdoc_free
 Free all resources of a parser.  The pointer is no longer valid after
 invocation.
 .It Fn mdoc_free
 Free all resources of a parser.  The pointer is no longer valid after
 invocation.

+.\" LIST-ITEM

 .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_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.

+.\" LIST-ITEM

 .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_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.

+.\" LIST-ITEM

 .It Fn mdoc_node
 Returns the first node of the parse.  Note that if 
 .Fn mdoc_parseln
 .It Fn mdoc_node
 Returns the first node of the parse.  Note that if 
 .Fn mdoc_parseln


@@ -88,20 +167,165 @@ or
 .Fn mdoc_endparse
 return 0, the data will be incomplete.
 .El
 .Fn mdoc_endparse
 return 0, the data will be incomplete.
 .El

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

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

-.Bl -ohang -offset indent
+.Bl -ohang -offset "XXXX"
+.\" LIST-ITEM

 .It Va mdoc_macronames
 An array of string-ified token names.
 .It Va mdoc_macronames
 An array of string-ified token names.

+.\" LIST-ITEM

 .It Va mdoc_argnames
 An array of string-ified token argument names.
 .El
 .It Va mdoc_argnames
 An array of string-ified token argument names.
 .El

+.\" SUBSECTION
+.Ss Character Encoding
+The
+.Xr mdoc 3
+library accepts only printable ASCII characters as defined by
+.Xr isprint 3 .
+Non-ASCII character sequences are delimited in various ways.  All are
+preceeded by an escape character
+.Sq \\
+and followed by either an open-parenthesis 
+.Sq \&(
+for two-character sequences; an open-bracket
+.Sq \&[
+for n-character sequences (terminated at a close-bracket
+.Sq \&] ) ;
+an asterisk and open-parenthesis
+.Sq \&*(
+for two-character sequences;
+an asterisk and non-open-parenthesis 
+.Sq \&*
+for single-character sequences; or one of a small set of standalone
+single characters for other escapes.
+.\" PARAGRAPH
+.Pp
+Examples:

 .Pp
 .Pp

+.Bl -tag -width "XXXXXXXX" -offset "XXXX" -compact
+.\" LIST-ITEM
+.It \\*(<=
+prints 
+.Dq \*(<=
+.Pq greater-equal
+.\" LIST-ITEM
+.It \\(<-
+prints
+.Dq \(<-
+.Pq left-arrow
+.\" LIST-ITEM
+.It \\[<-]
+also prints
+.Dq \(<-
+.Pq left-arrow
+.\" LIST-ITEM
+.It \\*(Ba
+prints
+.Dq \*(Ba
+.Pq bar
+.\" LIST-ITEM
+.It \\*q
+prints
+.Dq \*q
+.Pq double-quote
+.El
+.\" PARAGRAPH
+.Pp
+All escaped sequences are syntax-checked, but it's up to the front-end
+system to correctly render them to the output device.
+.\" SUBSECTION
+.Ss Abstract Syntax Tree
+The 

 .Nm
 .Nm

-is
-.Ud
-.\" 
+functions produce an abstract syntax tree (AST) describing the input
+lines 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.
+.\" PARAGRAPH
+.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 next 
+and
+.Va prev 
+fields) and type-specific data (the
+.Va data
+field).
+.\" PARAGRAPH
+.Pp
+The tree itself is arranged according to the following normal form,
+where capitalised non-terminals represent nodes.
+.Pp
+.Bl -tag -width "ELEMENTXX" -compact -offset "XXXX"
+.\" LIST-ITEM
+.It ROOT
+\(<- mnode+
+.It mnode
+\(<- BLOCK | ELEMENT | TEXT
+.It BLOCK
+\(<- (HEAD [TEXT])+ [BODY [TEXT]] [TAIL [TEXT]]
+.It BLOCK
+\(<- BODY [TEXT] [TAIL [TEXT]]
+.It ELEMENT
+\(<- TEXT*
+.It HEAD
+\(<- mnode+
+.It BODY
+\(<- mnode+
+.It TAIL
+\(<- mnode+
+.It TEXT
+\(<- [[:alpha:]]*
+.El
+.\" PARAGRAPH
+.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.
+.\" PARAGRAPH
+.Pp
+The rule-of-thumb for mapping node types to macros follows. In-line
+elements, such as 
+.Sq \&.Em foo ,
+are classified as ELEMENT nodes, which can only contain text.
+Multi-line elements, such as
+.Sq \&.Sh ,
+are BLOCK elements, where the HEAD constitutes line contents and the
+BODY constitutes subsequent lines.  In-line elements with matching
+pairs, such as
+.Sq \&.So
+and
+.Sq \&.Sc ,
+are BLOCK elements with no HEAD tag.  The only exception to this is
+.Sq \&.Eo 
+and
+.Sq \&.Ec ,
+which has a HEAD and TAIL node corresponding to the enclosure string.
+TEXT nodes, obviously, constitute text, and the ROOT node is the
+document's root.
+.\" SECTION

 .Sh EXAMPLES
 The following example reads lines from stdin and parses them, operating
 on the finished parse tree with 
 .Sh EXAMPLES
 The following example reads lines from stdin and parses them, operating
 on the finished parse tree with 


@@ -110,7 +334,7 @@ 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.
 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
+.Bd -literal -offset "XXXX"

 struct mdoc *mdoc;
 struct mdoc_node *node;
 char *buf;
 struct mdoc *mdoc;
 struct mdoc_node *node;
 char *buf;


@@ -135,21 +359,19 @@ if (NULL == (node = mdoc_node(mdoc)))
 parsed(mdoc, node);
 mdoc_free(mdoc);
 .Ed
 parsed(mdoc, node);
 mdoc_free(mdoc);
 .Ed

-.\"
+.\" SECTION

 .Sh SEE ALSO
 .Xr mdoc 7 ,
 .Xr mdoc.samples 7 ,
 .Xr groff 1 ,
 .Xr mdocml 1
 .Sh SEE ALSO
 .Xr mdoc 7 ,
 .Xr mdoc.samples 7 ,
 .Xr groff 1 ,
 .Xr mdocml 1

-.\"
-.\"
+.\" SECTION

 .Sh AUTHORS
 The
 .Nm
 utility was written by 
 .An Kristaps Dzonsons Aq kristaps@kth.se .
 .Sh AUTHORS
 The
 .Nm
 utility was written by 
 .An Kristaps Dzonsons Aq kristaps@kth.se .

-.\"
-.\"
+.\" SECTION

 .Sh BUGS
 Bugs, un-implemented macros and incompabilities are documented in this
 section.  The baseline for determining whether macro parsing is 
 .Sh BUGS
 Bugs, un-implemented macros and incompabilities are documented in this
 section.  The baseline for determining whether macro parsing is 


@@ -158,6 +380,7 @@ is the default
 .Xr groff 1
 system bundled with 
 .Ox .
 .Xr groff 1
 system bundled with 
 .Ox .

+.\" PARAGRAPH

 .Pp
 Un-implemented: the 
 .Sq \&Xc
 .Pp
 Un-implemented: the 
 .Sq \&Xc


@@ -167,12 +390,19 @@ macros aren't handled when used to span lines for the
 .Sq \&It
 macro.  Such usage is specifically discouraged in
 .Xr mdoc.samples 7 .
 .Sq \&It
 macro.  Such usage is specifically discouraged in
 .Xr mdoc.samples 7 .

+.\" PARAGRAPH

 .Pp
 Bugs: when 
 .Sq \&It \-column
 is invoked, whitespace is not stripped around
 .Sq \&Ta
 or tab-character separators.
 .Pp
 Bugs: when 
 .Sq \&It \-column
 is invoked, whitespace is not stripped around
 .Sq \&Ta
 or tab-character separators.

+.\" PARAGRAPH
+.Pp
+Bugs: elements within columns for
+.Sq \&It \-column
+are not yet supported.
+.\" PARAGRAPH

 .Pp
 Incompatible: the 
 .Sq \&At
 .Pp
 Incompatible: the 
 .Sq \&At


@@ -180,3 +410,16 @@ macro only accepts a single parameter.  Furthermore, several macros
 .Pf ( Sq \&Pp ,
 .Sq \&It ,
 and possibly others) accept multiple arguments with a warning.
 .Pf ( Sq \&Pp ,
 .Sq \&It ,
 and possibly others) accept multiple arguments with a warning.

+.\" PARAGRAPH
+.Pp
+Incompatible: only those macros specified by
+.Xr mdoc.samples 7
+and
+.Xr mdoc 7
+for
+.Ox
+are supported; support for
+.Nx
+and other 
+.Bx
+systems is in progress.