plucky (3) mandoc.3.gz

Provided by: libmandoc-dev_1.14.6-3_amd64 bug

NAME

     mandoc, deroff, mparse_alloc, mparse_copy, mparse_free, mparse_open, mparse_readfd, mparse_reset,
     mparse_result — mandoc macro compiler library

SYNOPSIS

     #include <sys/types.h>
     #include <stdio.h>
     #include <mandoc.h>

     #define ASCII_NBRSP
     #define ASCII_HYPH
     #define ASCII_BREAK

     struct mparse *
     mparse_alloc(int options, enum mandoc_os oe_e, char *os_s);

     void
     mparse_free(struct mparse *parse);

     void
     mparse_copy(const struct mparse *parse);

     int
     mparse_open(struct mparse *parse, const char *fname);

     void
     mparse_readfd(struct mparse *parse, int fd, const char *fname);

     void
     mparse_reset(struct mparse *parse);

     struct roff_meta *
     mparse_result(struct mparse *parse);

     #include <roff.h>

     void
     deroff(char **dest, const struct roff_node *node);

     #include <sys/types.h>
     #include <mandoc.h>
     #include <mdoc.h>

     extern const char * const * mdoc_argnames;
     extern const char * const * mdoc_macronames;

     #include <sys/types.h>
     #include <mandoc.h>
     #include <man.h>

     extern const char * const * man_macronames;

DESCRIPTION

     The mandoc library parses a UNIX manual into an abstract syntax tree (AST).  UNIX manuals are composed of
     mdoc(7) or man(7), and may be mixed with roff(7), tbl(7), and eqn(7) invocations.

     The following describes a general parse sequence:

     1.   initiate a parsing sequence with mchars_alloc(3) and mparse_alloc();

     2.   open a file with open(2) or mparse_open();

     3.   parse it with mparse_readfd();

     4.   close it with close(2);

     5.   retrieve the syntax tree with mparse_result();

     6.   if information about the validity of the input is needed, fetch it with mparse_updaterc();

     7.   iterate over parse nodes with starting from the first member of the returned struct roff_meta;

     8.   free all allocated memory with mparse_free() and mchars_free(3), or invoke mparse_reset() and go back
          to step 2 to parse new files.

REFERENCE

     This section documents the functions, types, and variables available via <mandoc.h>, with the exception of
     those documented in mandoc_escape(3) and mchars_alloc(3).

   Types
     enum mandocerr
     An error or warning message during parsing.

     enum mandoclevel
     A classification of an enum mandocerr as regards system operation.  See the DIAGNOSTICS section in
     mandoc(1) regarding the meanings of the levels.

     struct mparse
     An opaque pointer to a running parse sequence.  Created with mparse_alloc() and freed with mparse_free().
     This may be used across parsed input if mparse_reset() is called between parses.

   Functions
     deroff()
     Obtain a text-only representation of a struct roff_node, including text contained in its child nodes.  To
     be used on children of the first member of struct roff_meta.  When it is no longer needed, the pointer
     returned from deroff() can be passed to free(3).

     mparse_alloc()
     Allocate a parser.  The arguments have the following effect:

          options  When the MPARSE_MDOC or MPARSE_MAN bit is set, only that parser is used.  Otherwise, the
                   document type is automatically detected.

                   When the MPARSE_SO bit is set, roff(7) so file inclusion requests are always honoured.
                   Otherwise, if the request is the only content in an input file, only the file name is
                   remembered, to be returned in the sodest field of struct roff_meta.

                   When the MPARSE_QUICK bit is set, parsing is aborted after the NAME section.  This is for
                   example useful in makewhatis(8) -Q to quickly build minimal databases.

                   When the MARSE_VALIDATE bit is set, mparse_result() runs the validation functions before
                   returning the syntax tree.  This is almost always required, except in certain debugging
                   scenarios, for example to dump unvalidated syntax trees.

          os_e     Operating system to check base system conventions for.  If MANDOC_OS_OTHER, the system is
                   automatically detected from Os, -Ios, or uname(3).

          os_s     A default string for the mdoc(7) Os macro, overriding the OSNAME preprocessor definition and
                   the results of uname(3).  Passing NULL sets no default.

     The same parser may be used for multiple files so long as mparse_reset() is called between parses.
     mparse_free() must be called to free the memory allocated by this function.  Declared in <mandoc.h>,
     implemented in read.c.

     mparse_free()
     Free all memory allocated by mparse_alloc().  Declared in <mandoc.h>, implemented in read.c.

     mparse_copy()
     Dump a copy of the input to the standard output; used for -man -Tman.  Declared in <mandoc.h>, implemented
     in read.c.

     mparse_open()
     Open the file for reading.  If that fails and fname does not already end in ‘.gz’, try again after
     appending ‘.gz’.  Save the information whether the file is zipped or not.  Return a file descriptor open
     for reading or -1 on failure.  It can be passed to mparse_readfd() or used directly.  Declared in
     <mandoc.h>, implemented in read.c.

     mparse_readfd()
     Parse a file descriptor opened with open(2) or mparse_open().  Pass the associated filename in fname.  This
     function may be called multiple times with different parameters; however, close(2) and mparse_reset()
     should be invoked between parses.  Declared in <mandoc.h>, implemented in read.c.

     mparse_reset()
     Reset a parser so that mparse_readfd() may be used again.  Declared in <mandoc.h>, implemented in read.c.

     mparse_result()
     Obtain the result of a parse.  Declared in <mandoc.h>, implemented in read.c.

   Variables
     man_macronames
     The string representation of a man(7) macro as indexed by enum mant.

     mdoc_argnames
     The string representation of an mdoc(7) macro argument as indexed by enum mdocargt.

     mdoc_macronames
     The string representation of an mdoc(7) macro as indexed by enum mdoct.

IMPLEMENTATION NOTES

     This section consists of structural documentation for mdoc(7) and man(7) syntax trees and strings.

   Man and Mdoc Strings
     Strings may be extracted from mdoc and man meta-data, or from text nodes (MDOC_TEXT and MAN_TEXT,
     respectively).  These strings have special non-printing formatting cues embedded in the text itself, as
     well as roff(7) escapes preserved from input.  Implementing systems will need to handle both situations to
     produce human-readable text.  In general, strings may be assumed to consist of 7-bit ASCII characters.

     The following non-printing characters may be embedded in text strings:

     ASCII_NBRSP
             A non-breaking space character.

     ASCII_HYPH
             A soft hyphen.

     ASCII_BREAK
             A breakable zero-width space.

     Escape characters are also passed verbatim into text strings.  An escape character is a sequence of
     characters beginning with the backslash (‘\’).  To construct human-readable text, these should be
     intercepted with mandoc_escape(3) and converted with one the functions described in mchars_alloc(3).

   Man Abstract Syntax Tree
     This AST is governed by the ontological rules dictated in man(7) and derives its terminology accordingly.

     The AST is composed of struct roff_node nodes with element, root and text types as declared by the type
     field.  Each node also provides its parse point (the line, pos, and sec fields), its position in the tree
     (the parent, child, next and prev fields) and some type-specific data.

     The tree itself is arranged according to the following normal form, where capitalised non-terminals
     represent nodes.

     ROOT       ← mnode+
     mnode      ← ELEMENT | TEXT | BLOCK
     BLOCK      ← HEAD BODY
     HEAD       ← mnode*
     BODY       ← mnode*
     ELEMENT    ← ELEMENT | TEXT*
     TEXT       ← [[:ascii:]]*

     The only elements capable of nesting other elements are those with next-line scope as documented in man(7).

   Mdoc Abstract Syntax Tree
     This AST is governed by the ontological rules dictated in mdoc(7) and derives its terminology accordingly.
     "In-line" elements described in mdoc(7) are described simply as "elements".

     The AST is composed of struct roff_node nodes with block, head, body, element, root and text types as
     declared by the type field.  Each node also provides its parse point (the line, pos, and sec fields), its
     position in the tree (the parent, child, last, next and prev fields) and some type-specific data, in
     particular, for nodes generated from macros, the generating macro in the tok field.

     The tree itself is arranged according to the following normal form, where capitalised non-terminals
     represent nodes.

     ROOT       ← mnode+
     mnode      ← BLOCK | ELEMENT | TEXT
     BLOCK      ← HEAD [TEXT] (BODY [TEXT])+ [TAIL [TEXT]]
     ELEMENT    ← TEXT*
     HEAD       ← mnode*
     BODY       ← mnode* [ENDBODY mnode*]
     TAIL       ← mnode*
     TEXT       ← [[:ascii:]]*

     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 ‘.Bd -literal’, an empty line will produce a zero-length string.  Multiple body parts are
     only found in invocations of ‘Bl -column’, where a new body introduces a new phrase.

     The mdoc(7) syntax tree accommodates for broken block structures as well.  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
     end field, is of the BODY type, has the same tok as the BLOCK it is ending, and has a 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.

     An ENDBODY node is generated when a block ends while one of its child blocks is still open, like in the
     following example:

           .Ao ao
           .Bo bo ac
           .Ac bc
           .Bc end

     This example results in the following block structure:

           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

     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.  It renders as follows in -Tascii mode:

           <ao [bo ac> bc] end

     Support for badly-nested blocks is only provided for backward compatibility with some older mdoc(7)
     implementations.  Using badly-nested blocks is strongly discouraged; for example, the -Thtml front-end to
     mandoc(1) is 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.

SEE ALSO

     mandoc(1), man.cgi(3), mandoc_escape(3), mandoc_headers(3), mandoc_malloc(3), mansearch(3),
     mchars_alloc(3), tbl(3), eqn(7), man(7), mandoc_char(7), mdoc(7), roff(7), tbl(7)

AUTHORS

     The mandoc library was written by Kristaps Dzonsons <kristaps@bsd.lv> and is maintained by Ingo Schwarze
     <schwarze@openbsd.org>.