Handle nested, recursive mathematical subexpressions. This is

[mandoc.git] / mdoc.3

diff --git a/mdoc.3 b/mdoc.3
index 8dd79ffd3bd674710e0cd7a79403b79bbde9650b..3620b15552a9720da17e5379083029a5af928ecb 100644 (file)
--- a/mdoc.3
+++ b/mdoc.3
@@ -1,192 +1,367 @@
-.\" 
-.Dd $Mdocdate: January 20 2009 $
-.Dt mdoc 3
-.Os
+.\"    $Id: mdoc.3,v 1.49 2010/08/20 01:02:07 schwarze Exp $
+.\"
+.\" 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: August 20 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 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 "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 .
+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
+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
 .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, 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 .