.\" $Id$ .\" .\" Copyright (c) 2009, 2010 Kristaps Dzonsons .\" Copyright (c) 2010 Ingo Schwarze .\" .\" 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 $Mdocdate$ .Dt MDOC 3 .Os .Sh NAME .Nm mdoc , .Nm mdoc_alloc , .Nm mdoc_endparse , .Nm mdoc_free , .Nm mdoc_meta , .Nm mdoc_node , .Nm mdoc_parseln , .Nm mdoc_reset .Nd mdoc macro compiler library .Sh SYNOPSIS .In mandoc.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 *" .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 "const struct mdoc_meta *" .Fn mdoc_meta "const struct mdoc *mdoc" .Ft "const struct mdoc_node *" .Fn mdoc_node "const struct mdoc *mdoc" .Ft int .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 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 , 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_node 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. .Ss Types .Bl -ohang .It Vt struct mdoc An opaque type. Its values are only used privately within the library. .It Vt struct mdoc_node A parsed node. See .Sx Abstract Syntax Tree for details. .El .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 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(®s, sizeof(struct regset)); line = 1; mdoc = mdoc_alloc(®s, 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 .