%%% ====================================================================
%%%  @BibTeX-style-file{
%%%     author          = "David M. Jones",
%%%     version         = "1.00",
%%%     date            = "27 October 1993",
%%%     time            = "15:21:11 EDT",
%%%     filename        = "hilbert.bst",
%%%     address         = "MIT Laboratory for Computer Science
%%%                        Room NE43-316
%%%                        545 Technology Square
%%%                        Cambridge, MA 02139
%%%                        USA",
%%%     telephone       = "(617) 253-5936",
%%%     FAX             = "(617) 253-3480",
%%%     checksum        = "47437 2344 8786 62605",
%%%     email           = "dmjones@theory.lcs.mit.edu",
%%%     codetable       = "ISO/ASCII",
%%%     keywords        = "",
%%%     supported       = "yes",
%%%     docstring       = "This is a BibTeX style file that implements
%%%                        a bibliography format similar to that used
%%%                        by Yuri Matijasevich in is book {\em
%%%                        Hilbert's Tenth Problem\/} (MIT Press,
%%%                        1993).  This file is not identical to the
%%%                        one used for the book; it has been modified
%%%                        in an attempt to make it more generally
%%%                        useful.  However, it is still deficient in
%%%                        one big way -- the \cite command is not
%%%                        supported.  (For historical reasons, we
%%%                        didn't use the \cite command in our book,
%%%                        and so I didn't bother implementing it in
%%%                        this style file.)  If there is sufficient
%%%                        interest, I'll try to remedy this defect.
%%%
%%%                        This file has been released for public use
%%%                        with the kind permission of MIT Press.
%%%
%%%                        This file is originally based upon the file
%%%                        plain.bst by Oren Patashnik, but has been
%%%                        massively modified.
%%%
%%%                        This and related files are available via
%%%                        anonymous ftp from theory.lcs.mit.edu in
%%%                        the directory pub/hilbert10.  See the file
%%%                        ``README'' in that directory for a list and
%%%                        description of what is available.
%%%
%%%                        The checksum field above contains a CRC-16
%%%                        checksum as the first value, followed by the
%%%                        equivalent of the standard UNIX wc (word
%%%                        count) utility output of lines, words, and
%%%                        characters.  This is produced by Robert
%%%                        Solovay's checksum utility.",
%%%  }
%%% ====================================================================

%   Entry formatting: Similar to that recommended by Mary-Claire van
%       Leunen in "A Handbook for Scholars".  Book-like titles are
%       italicized (emphasized) and non-book titles are converted to
%       sentence capitilization (and not enclosed in quotes).  This
%       file outputs a \newblock between major blocks of an entry (the
%       name \newblock is analogous to the names \newline and
%       \newpage) so that the user can obtain an "open" format, which
%       has a line break before each block and lines after the first
%       are indented within blocks, by giving the optional
%       \documentstyle argument `openbib'; The default is the "closed"
%       format---blocks runs together.  The month field is suppressed.
%
%       In the bibliography produced by this file, papers are arranged
%       alphabetically by author and then listed by year, in the
%       following format:
%
%           Zofia Adamowicz
%
%           1992    A sharp version of the bounded {Matijasevich}
%                   conjecture and the end-extension problem. {\em
%                   Journal of Symbolic Logic}, 57(2):597--616.
%
%           Andrew Adler
%
%           1969a   Existential formulas in arithmetic. {\em
%                   Dissertation Abstracts}, 29B(8):2962--2963.
%
%           1969b   Extensions of non-standard models of number
%                   theory. {\em Zeitschrift f{\"u}r Mathematische
%                   Logik und Grundlagen der Mathematik},
%                   15(4):289--290.
%
%           1969c   Some recursively unsolvable problems in analysis.
%                   {\em Proceedings of the American Mathematical
%                   Society}, 22(2):523--526.
%
%           1971    A.~Adler. A reduction of homogeneous {Diophantine}
%                   problems.  {\em The Journal of the London
%                   Mathematical Society (Second Series)},
%                   3(3):446--448.
%
%       The actual LaTeX code produced looks something like this:
%
%           \bibauthor{Zofia Adamowicz}
%
%           \begin{paperlist}
%
%           \item[1992]
%           A sharp version of the bounded {Matijasevich} conjecture
%           and the end-extension problem.
%           \newblock {\em Journal of Symbolic Logic}, 57(2):597--616.
%
%           \end{paperlist}
%
%       The macro \bibauthor and the environment \paperlist are
%       defined in the file hilbert.sty.
%
%       In some cases, an author's name will appear in different ways
%       on different papers, which provides a dilemma: on one hand,
%       it's necessary to give the author's name uniformly in order
%       for an author's papers to be correctly grouped together as
%       above.  On the other hand, it's desirable to indicate the
%       precise spelling of the author's name in the bibliography,
%       especially when the variant spellings are a matter of
%       different transliterations of a name.  The sort-author field
%       is provided to deal with this contigency.  Suppose you have
%       three papers by John Q. Smith in your bibliography.  On two of
%       the papers, his name appears as "John Q. Smith", while on the
%       third it is listed as as "J. Smith".  In each case, the author
%       field would be given precisely as the name appeared on the
%       article, but the third paper would also have a sort-author
%       field containing "John Q. Smith".  The final bibliography
%       would end up looking something like this:
%
%           John Q. Smith
%
%           1980    Paper title 1....
%
%           1981    Paper title 1....
%
%           1982    J. Smith.  Paper title 3....
%
%
%   Citation label format:
%       Author [1993]
%       Author1 and Author2 [1993]
%       Author1, Author 2, and Author 3 [1993]
%

% The ENTRY declaration
%   Like Scribe's (according to pages 231-2 of the April '84 edition),
%   but no fullauthor or editors fields because BibTeX does name
%   handling.  The annote field is commented out here because this
%   family doesn't include an annotated bibliography style.  And in
%   addition to the fields listed here, BibTeX has a built-in crossref
%   field, explained later.

ENTRY
% Fields:
  {
    abstract
%
    address
%           Usually the address of a publisher or other type of
%           organization.  Put information in this field only if it
%           helps the reader find the thing---for example you should
%           omit the address of a major publisher entirely.  For a
%           PROCEEDINGS or an INPROCEEDINGS, however, it's the address
%           of the conference; for those two entry types, include the
%           publisher's or organization's address, if necessary, in
%           the publisher or organization field.
    author
%           Name(s) of author(s), in BibTeX name format.
    sort-author
%           See above for an explanation of this field.
    booktitle
%           Book title when the thing being referenced isn't the whole
%           book.  For book entries, the title field should be used
%           instead.
    chapter
%           Chapter (or section or whatever) number.
    crossrefonly
%           added by dmj
%           Hack to add flexibility in crossref feature
    edition
%           Edition of a book---should be an ordinal (e.g., "Second").
    editor
%           Name(s) of editor(s), in BibTeX name format.  If there is
%           also an author field, then the editor field should be for
%           the book or collection that the work appears in.
    howpublished
%            How something strange has been published (begins sentence).
    institution
%           Sponsoring institution of a technical report.
    journal
%           Journal name (macros are provided for many).
    key
%           Alphabetizing, labeling, and cross-referencing key
%           (needed when an entry has no author or editor).
    language
    month
%           Month (macros are provided).  The month field is not used
%           in this style.
    note
%           To help the reader find a reference (begins sentence).
    number
%           Number of a journal or technical report, or of a work in a
%           series.
    organization
%           Organization sponsoring a conference (or publishing a
%           manual); if the editor (or author) is empty, and if the
%           organization produces an awkward label or cross reference,
%           you should put appropriately condensed organization
%           information in the key field as well.
    pages
%           Page number or numbers (use `--' to separate a range, use
%           `+' to indicate pages following that don't form a simple
%           range).
    publisher
%           Publisher name.
    sortgroup
%           key used to group entries together when doing sorting
%           v1.01
    sortkey
%           key used to alter the position of a particular entry
%           v1.01
    school
%           School name (for theses).
    series
%           The name of a series or set of books.
%           An individual book will will also have it's own title.
    subyear
    title
%           The title of the thing you're referred to.
    translation
    type
%           Type of a Techreport (e.g., "Research Note") to be used
%           instead of the default "Technical Report"; or, similarly,
%           the type of a thesis; or of a part of a book.
    volume
%           The volume number of a journal or multivolume work.
    year
%           The year should contain only numerals (technically, it
%           should end with four numerals, after purification; doesn't
%           a begin sentence).
  }
% There are no integer entry variables
  {}
% These string entry variables are used to form the citation label.
% In a storage pinch, sort.label can be easily computed on the fly.
  { label extra.label }

% These three functions pop one or two (integer) arguments from the
% stack and push a single one, either 0 or 1.  The 'skip$ in the `and'
% and `or' functions are used because the corresponding if$ would be
% idempotent

FUNCTION {not}
{   { #0 }
    { #1 }
  if$
}

FUNCTION {and}
{   'skip$
    { pop$ #0 }
  if$
}

FUNCTION {or}
{   { pop$ #1 }
    'skip$
  if$
}

% Each entry function starts by calling output.bibitem, to write the
% \bibitem and its arguments to the .BBL file.  It also decides
% whether to start a new paperlist or to continue the current one
% (i.e., it checks to see if the author has changed since the previous
% entry and, if so, ends the old paperlist and starts a new one).
% Then the various fields are formatted and printed by output or
% output.check.  Those functions handle the writing of separators
% (commas, periods, \newblock's), taking care not to do so when they
% are passed a null string.  Finally, fin.entry is called to add the
% final period, format the translation field and finish the entry.
% (fin.entry also optionally calls the function output.language.end to
% close the group began by output.language.begin.)
%
% A bibliographic reference is formatted into a number of `blocks': in
% the open format, a block begins on a new line and subsequent lines
% of the block are indented.  A block may contain more than one
% sentence (well, not a grammatical sentence, but something to be
% ended with a sentence ending period).  The entry functions should
% call new.block whenever a block other than the first is about to be
% started.  They should call new.sentence whenever a new sentence is
% to be started.  The output functions will ensure that if two
% new.sentence's occur without any non-null string being output
% between them then there won't be two periods output.  Similarly for
% two successive new.block's.
%
% The output routines don't write their argument immediately.
% Instead, by convention, that argument is saved on the stack to be
% output next time (when we'll know what separator needs to come after
% it).  Meanwhile, the output routine has to pop the pending output
% off the stack, append any needed separator, and write it.
%
% To tell which separator is needed, we maintain an output.state.  It
% will be one of these values:
%       before.all              just after the \bibitem
%       mid.sentence            in the middle of a sentence: comma
%                               needed if more sentence is output
%       after.sentence          just after a sentence: period needed
%       after.block             just after a block (and sentence):
%                                       period and \newblock needed.
% Note: These styles don't use after.sentence
%
% VAR: output.state : INTEGER           -- state variable for output
%
% The output.nonnull function saves its argument (assumed to be
% nonnull) on the stack, and writes the old saved value followed by
% any needed separator.  The ordering of the tests is decreasing
% frequency of occurrence.
%
% output.nonnull(s) ==
%  BEGIN
%       s := argument on stack
%       if output.state = mid.sentence then
%           write$(pop() * ", ")
%                 -- "pop" isn't a function: just use stack top
%       else
%           if output.state = after.block then
%               write$(add.period$(pop()))
%               newline$
%               write$("\newblock ")
%           else
%               if output.state = before.all then
%                   write$(pop())
%               else        -- output.state should be after.sentence
%                   write$(add.period$(pop()) * " ")
%               fi
%           fi
%           output.state := mid.sentence
%       fi
%       push s on stack
%  END
%
% The output function calls output.nonnull if its argument is
% non-empty; its argument may be a missing field (thus, not
% necessarily a string)
%
% output(s) ==
%  BEGIN
%       if not empty$(s) then output.nonnull(s)
%       fi
%  END
%
% The output.check function is the same as the output function except
% that, if necessary, output.check warns the user that the t field
% shouldn't be empty (this is because it probably won't be a good
% reference without the field; the entry functions try to make the
% formatting look reasonable even when such fields are empty).
%
% output.check(s,t) ==
%  BEGIN
%       if empty$(s) then
%           warning$("empty " * t * " in " * cite$)
%       else output.nonnull(s)
%       fi
%  END
%
% The output.bibitem checks the extra.label field to see if it is
% "\bysame".  If so, this means that the current item has the same
% author as the previous item, so no special action is needed.
% Otherwise, it calls begin.new.author to end the old paperlist,
% output a new \bibauthor command, and begin a paperlist environment.
% It also leaves a string on the stack as per the output convention
% and initializes the output.state to "before.all".
%
% output.bibitem ==
%  BEGIN
%       if not(empty$(author))
%           begin.new.author
%       fi
%       push "" on stack
%       output.state := before.all
%  END
%
% The fin.entry function finishes off an entry by adding a period to
% the string remaining on the stack.  If the state is still before.all
% then nothing was produced for this entry, so the result will look
% bad, but the user deserves it. (We don't omit the whole entry
% because the entry was cited, and a bibitem is needed to define the
% citation label.)
%
% fin.entry ==
%  BEGIN
%       write$(add.period$(pop()))
%       format.translation
%       %output.language.end  %commented out in this version
%       newline$
%  END
%
% The new.block function prepares for a new block to be output, and
% new.sentence prepares for a new sentence.
%
% new.block ==
%  BEGIN
%       if output.state <> before.all then
%           output.state := after.block
%       fi
%  END
%
% new.sentence ==
%  BEGIN
%       if output.state <> after.block then
%           if output.state <> before.all then
%               output.state :=  after.sentence
%           fi
%       fi
%  END
%

INTEGERS { beginning output.state before.all mid.sentence
after.sentence after.block }

FUNCTION {init.state.consts}
{ #0 'before.all :=
  #1 'mid.sentence :=
  #2 'after.sentence :=
  #3 'after.block :=
}

% the variables s and t are temporary string holders

STRINGS { s t }

FUNCTION {output.nonnull}
{ 's :=
  output.state mid.sentence =
    { ", " * write$ }
    { output.state after.block =
        { add.period$ write$
          newline$
          "\newblock " write$
        }
        { output.state before.all =
            'write$
            { add.period$ " " * write$ }
          if$
        }
      if$
      mid.sentence 'output.state :=
    }
  if$
  s
}

FUNCTION {output}
{ duplicate$ empty$
    'pop$
    'output.nonnull
  if$
}

FUNCTION {output.check}
{ 't :=
  duplicate$ empty$
    { pop$ "empty " t * " in " * cite$ * warning$ }
    'output.nonnull
  if$
}

FUNCTION {output.language.begin}
{""}
%%  { ""
%%    language empty$
%%      'skip$
%%      {
%%        language "Russian" =
%%          { pop$ "\bibcyr " }
%%          'skip$
%%        if$
%%        language "German" =
%%          { pop$ "\selectlanguage{germanb}" }
%%          'skip$
%%        if$
%%      }
%%    if$
%%  }

FUNCTION {output.language.begin.group}
{""}
%%  { ""
%%    language empty$
%%      'skip$
%%      {
%%        language "Russian" =
%%          { pop$ "{\bibcyr " }
%%          'skip$
%%        if$
%%        language "German" =
%%          { pop$ "{\selectlanguage{germanb}" }
%%          'skip$
%%        if$
%%      }
%%    if$
%%  }

FUNCTION {output.language.end}
{""}
%%  { ""
%%    language empty$
%%      'skip$
%%      { language "Russian" =
%%        language "German" =
%%          or
%%         { pop$ "}" }
%%         'skip$
%%        if$
%%      }
%%    if$
%%  }

FUNCTION {format.language}
{ language empty$
    { "" }
    { " (" language * ")" * }
  if$
}

FUNCTION {format.translation}
{}
%%  { translation empty$
%%      'skip$
%%      {
%%          " {\selectlanguage{english} (Translated as "
%%          translation *
%%          ")}" *
%%          write$
%%      }
%%    if$
%%  }

% This function finishes all entries.

FUNCTION {fin.entry}
{ add.period$
  write$
  format.translation
%  output.language.end
  newline$
}

FUNCTION {new.block}
{ output.state before.all =
    'skip$
    { after.block 'output.state := }
  if$
}

FUNCTION {new.sentence}
{ output.state after.block =
    'skip$
    { output.state before.all =
        'skip$
        { after.sentence 'output.state := }
      if$
    }
  if$
}

% Sometimes we begin a new block only if the block will be big enough.
% The new.block.checka function issues a new.block if its argument is
% nonempty; new.block.checkb does the same if either of its TWO
% arguments is nonempty.

FUNCTION {new.block.checka}
{ empty$
    'skip$
    'new.block
  if$
}

FUNCTION {new.block.checkb}
{ empty$
  swap$ empty$
  and
    'skip$
    'new.block
  if$
}

% The new.sentence.check functions are analogous.

FUNCTION {new.sentence.checka}
{ empty$
    'skip$
    'new.sentence
  if$
}

FUNCTION {new.sentence.checkb}
{ empty$
  swap$ empty$
  and
    'skip$
    'new.sentence
  if$
}

% Here are some functions for formatting chunks of an entry.  By
% convention they either produce a string that can be followed by a
% comma or period (using add.period$, so it is OK to end in a period),
% or they produce the null string.
%
% A useful utility is the field.or.null function, which checks if the
% argument is the result of pushing a `missing' field (one for which
% no assignment was made when the current entry was read in from the
% database) or the result of pushing a string having no
% non-white-space characters.  It returns the null string if so,
% otherwise it returns the field string.  Its main (but not only)
% purpose is to guarantee that what's left on the stack is a string
% rather than a missing field.
%
% field.or.null(s) ==
%  BEGIN
%       if empty$(s) then return ""
%       else return s
%  END
%
% Another helper function is emphasize, which returns the argument
% emphazised, if that is non-empty, otherwise it returns the null
% string.  Italic corrections aren't used, so this function should be
% used when punctation will follow the result.
%
% emphasize(s) ==
%  BEGIN
%       if empty$(s) then return ""
%       else return "{\em " * s * "}"
%
% The format.names function formats the argument (which should be in
% BibTeX name format) into "First Von Last, Junior", separated by
% commas and with an "and" before the last (but ending with "et~al."
% if the last of multiple authors is "others").  This function's
% argument should always contain at least one name.
%
% VAR: nameptr, namesleft, numnames: INTEGER
% pseudoVAR: nameresult: STRING     (it's what's accumulated on the
%                                   stack)
%
% format.names(s) ==
%  BEGIN
%    nameptr := 1
%    numnames := num.names$(s)
%    namesleft := numnames
%    while namesleft > 0
%      do
%                            % for full names:
%        t := format.name$(s, nameptr, "{ff~}{vv~}{ll}{, jj}")
%                            % for abbreviated first names:
%        t := format.name$(s, nameptr, "{f.~}{vv~}{ll}{, jj}")
%        if nameptr > 1 then
%            if namesleft > 1 then nameresult := nameresult * ", " * t
%            else if numnames > 2
%                   then nameresult := nameresult * ","
%                 fi
%                 if t = "others"
%                   then nameresult := nameresult * " et~al."
%                   else nameresult := nameresult * " and " * t
%                 fi
%            fi
%        else nameresult := t
%        fi
%        nameptr := nameptr + 1
%        namesleft := namesleft - 1
%      od
%    return nameresult
%  END
%
% The format.names.and.index function is identical to format.names
% except that it also calls the function format.name.index.entry.
%
% The format.authors function returns the result of
% format.names(author) if the author is present, or else it returns
% the null string
%
% format.authors ==
%  BEGIN
%       if empty$(author) then return ""
%       else return format.names(author)
%       fi
%  END
%
% Format.editors is like format.authors, but it uses the editor field,
% and appends ", editor" or ", editors"
%
% format.editors ==
%  BEGIN
%       if empty$(editor) then return ""
%       else
%           if num.names$(editor) > 1 then
%               return format.names(editor) * ", editors"
%           else
%               return format.names(editor) * ", editor"
%           fi
%       fi
%  END
%
% Other formatting functions are similar, so no "comment version" will
% be given for them.
%
% The `pop$' in this function gets rid of the duplicate `empty' value
% and the `skip$' returns the duplicate field value

FUNCTION {field.or.null}
{ duplicate$ empty$
    { pop$ "" }
    'skip$
  if$
}

FUNCTION {emphasize}
{ duplicate$ empty$
    { pop$ "" }
    { "{\em " swap$ * "}" * }
  if$
}

INTEGERS { nameptr namesleft numnames }

FUNCTION {format.names}
{ 's :=
  #1 'nameptr :=
  s num.names$ 'numnames :=
  numnames 'namesleft :=
    { namesleft #0 > }
    { s nameptr "{ff~}{vv~}{ll}{, jj}" format.name$ 't :=
      nameptr #1 >
        { namesleft #1 >
            { ", " * t * }
            { numnames #2 >
                { "," * }
                'skip$
              if$
              t "others" =
                { " et~al." * }
                { " and " * t * }
              if$
            }
          if$
        }
        't
      if$
      nameptr #1 + 'nameptr :=
      namesleft #1 - 'namesleft :=
    }
  while$
}

FUNCTION {format.name.index.entry}
{""}
%%  { "\index[aut]{"
%%    s nameptr "{vv{ }}{ll{ }}{, jj}" format.name$ *
%%    s nameptr "{, ff{ }}" format.name$ *
%%    "}" *
%%  }
%%

FUNCTION {format.names.and.index}
{ 's :=
  #1 'nameptr :=
  s num.names$ 'numnames :=
  numnames 'namesleft :=
    { namesleft #0 > }

    {
      format.name.index.entry
      s nameptr "{ff~}{vv~}{ll}{, jj}" format.name$ * 't :=

      nameptr #1 >
        { namesleft #1 >
            { ", " * t * }
            { numnames #2 >
                { "," * }
                'skip$
              if$
              t "others" =
                { " et~al." * }
                { " and " * t * }
              if$
            }
          if$
        }
        't
      if$
      nameptr #1 + 'nameptr :=
      namesleft #1 - 'namesleft :=
    }
  while$
}

% The variable "beginning" is 0 if this is the first item in the
% bibliography (i.e., if the .bbl file is empty), and 0 otherwise.

FUNCTION {begin.new.author}
{
    newline$
    beginning #0 =
        { #1 'beginning := }
        {
            "\end{paperlist}" write$
            newline$
            newline$
        }
    if$
    "\bibauthor{"
    output.language.begin *
    sort-author missing$
        { author }
        { sort-author }
    if$
    format.names.and.index
    "}" * * write$
    newline$
    newline$
    "\begin{paperlist}" write$
    newline$
}

FUNCTION {output.bibitem}
{
    author empty$
        'skip$
        { extra.label "\bysame" =
            'skip$
            { begin.new.author }
          if$
        }
    if$
    ""
    before.all 'output.state :=
}

FUNCTION {format.transliteration}
{
    sort-author purify$ author purify$ =
        'skip$
        { author format.names output }
    if$
}

FUNCTION {format.authors}
{
    ""
    before.all 'output.state :=
    sort-author empty$
        'skip$
        'format.transliteration
    if$

}

FUNCTION {format.editors}
{ editor empty$
    { "" }
    { editor format.names
      editor num.names$ #1 >
        { ", editors" * }
        { ", editor" * }
      if$
    }
  if$
}

% The format.title function is used for non-book-like titles.  For
% most styles we convert to lowercase (except for the very first
% letter, and except for the first one after a colon (followed by
% whitespace)), and hope the user has brace-surrounded words that need
% to stay capitilized; for some styles, however, we leave it as it is
% in the database.

FUNCTION {format.title}
{ title empty$
    { "" }
    {
      output.language.begin.group
      title "t" change.case$
      output.language.end * *
    }
  if$
}

% By default, BibTeX sets the global integer variable global.max$ to
% the BibTeX constant glob_str_size, the maximum length of a global
% string variable.  Analogously, BibTeX sets the global integer
% variable entry.max$ to ent_str_size, the maximum length of an entry
% string variable.  The style designer may change these if necessary
% (but this is unlikely)

% The n.dashify function makes each single `-' in a string a double
% `--' if it's not already
%
% pseudoVAR: pageresult: STRING     (it's what's accumulated on the
%                                   stack)
%
% n.dashify(s) ==
%  BEGIN
%       t := s
%       pageresult := ""
%       while (not empty$(t))
%         do
%           if (first character of t = "-")
%             then
%               if (next character isn't)
%                 then
%                   pageresult := pageresult * "--"
%                   t := t with the "-" removed
%                 else
%                   while (first character of t = "-")
%                     do
%                       pageresult := pageresult * "-"
%                       t := t with the "-" removed
%                     od
%               fi
%             else
%               pageresult := pageresult * the first character
%               t := t with the first character removed
%           fi
%         od
%       return pageresult
%  END

FUNCTION {n.dashify}
{ 't :=
  ""
    { t empty$ not }
    { t #1 #1 substring$ "-" =
        { t #1 #2 substring$ "--" = not
            { "--" *
              t #2 global.max$ substring$ 't :=
            }
            {   { t #1 #1 substring$ "-" = }
                { "-" *
                  t #2 global.max$ substring$ 't :=
                }
              while$
            }
          if$
        }
        { t #1 #1 substring$ *
          t #2 global.max$ substring$ 't :=
        }
      if$
    }
  while$
}

% The format.date function is for the month and year, but we give a
% warning if there's an empty year but the month is there, and we
% return the empty string if they're both empty.

FUNCTION {format.date}
{ year empty$
    { month empty$
        { "" }
        { "there's a month but no year in " cite$ * warning$
          month
        }
      if$
    }
    { month empty$
        { subyear empty$
            'year
            { year subyear * }
          if$
        }
        {
            month " " * year *
            subyear empty$
                'skip$
                { subyear * }
            if$
        }
      if$
    }
  if$
}

%%% ADD \bibitem HERE

FUNCTION {format.year}
{
    newline$
    "\item["
    year empty$
        { "" }
        { subyear empty$
            'year
            { year subyear * }
          if$
        }
    if$
    "]" * * write$
    newline$
    write$
%    output.language.begin
    before.all 'output.state :=
}

%%  FUNCTION {format.year}
%%  { year empty$
%%      { "" }
%%        { subyear empty$
%%           'year
%%            { year subyear * }
%%          if$
%%        }
%%    if$
%%  }

FUNCTION {format.month}
{ month empty$
    { "" }
    'month
  if$
}

% The format.btitle is for formatting the title field when it is a
% book-like entry---the style used here keeps it in uppers-and-lowers
% and emphasizes it.

FUNCTION {format.btitle}
{
    output.language.begin
    title * emphasize
}

% For several functions we'll need to connect two strings with a tie
% (~) if the second one isn't very long (fewer than 3 characters).
% The tie.or.space.connect function does that.  It concatenates the
% two strings on top of the stack, along with either a tie or space
% between them, and puts this concatenation back onto the stack:
%
% tie.or.space.connect(str1,str2) ==
%    BEGIN
%       if text.length$(str2) < 3
%         then return the concatenation of str1, "~", and str2
%         else return the concatenation of str1, " ", and str2
%    END

FUNCTION {tie.or.space.connect}
{ duplicate$ text.length$ #3 <
    { "~" }
    { " " }
  if$
  swap$ * *
}

% The either.or.check function complains if both fields or an
% either-or pair are nonempty.
%
% either.or.check(t,s) ==
%  BEGIN
%       if empty$(s) then
%           warning$(can't use both " * t * " fields in " * cite$)
%       fi
%  END

FUNCTION {either.or.check}
{ empty$
    'pop$
    { "can't use both " swap$ * " fields in " * cite$ * warning$ }
  if$
}

% The format.bvolume function is for formatting the volume and perhaps
% series name of a multivolume work.  If both a volume and a series
% field are there, we assume the series field is the title of the
% whole multivolume work (the title field should be the title of the
% thing being referred to), and we add an "of <series>".  This
% function is called in mid-sentence.

FUNCTION {format.bvolume}
{ volume empty$
    { "" }
    { "volume" volume tie.or.space.connect
      series empty$
        'skip$
        { " of " * series emphasize * }
      if$
      "volume and number" number either.or.check
    }
  if$
}

% The format.number.series function is for formatting the series name
% and perhaps number of a work in a series.  This function is similar
% to format.bvolume, although for this one the series must exist (and
% the volume must not exist).  If the number field is empty we output
% either the series field unchanged if it exists or else the null
% string.  If both the number and series fields are there we assume
% the series field gives the name of the whole series (the title field
% should be the title of the work being one referred to), and we add
% an "in <series>".  We capitilize Number when this function is used
% at the beginning of a block.

FUNCTION {format.number.series}
{ volume empty$
    { number empty$
        { series field.or.null }
        { output.state mid.sentence =
            { "number" }
            { "Number" }
          if$
          number tie.or.space.connect
          series empty$
            { "there's a number but no series in " cite$ * warning$ }
            { " in " * series * }
          if$
        }
      if$
    }
    { "" }
  if$
}

% The format.edition function appends " edition" to the edition, if
% present.  We lowercase the edition (it should be something like
% "Third"), because this doesn't start a sentence.

FUNCTION {format.edition}
{ edition empty$
    { "" }
    { output.state mid.sentence =
        { edition "l" change.case$ " edition" * }
        { edition "t" change.case$ " edition" * }
      if$
    }
  if$
}

% The format.pages function is used for formatting a page range in a
% book (and in rare circumstances, an article).
%
% The multi.page.check function examines the page field for a "-" or
% "," or "+" so that format.pages can use "page" instead of "pages" if
% none exists.  Note: global.max$ here means "take the rest of the
% string"
%
% VAR: multiresult: INTEGER     (actually, a boolean)
%
% multi.page.check(s) ==
%  BEGIN
%       t := s
%       multiresult := false
%       while ((not multiresult) and (not empty$(t)))
%         do
%           if (first character of t = "-" or "," or "+")
%             then multiresult := true
%             else t := t with the first character removed
%           fi
%         od
%       return multiresult
%  END

INTEGERS { multiresult }

FUNCTION {multi.page.check}
{ 't :=
  #0 'multiresult :=
    { multiresult not
      t empty$ not
      and
    }
    { t #1 #1 substring$
      duplicate$ "-" =
      swap$ duplicate$ "," =
      swap$ "+" =
      or or
        { #1 'multiresult := }
        { t #2 global.max$ substring$ 't := }
      if$
    }
  while$
  multiresult
}

% This function doesn't begin a sentence so "pages" isn't capitalized.
% Other functions that use this should keep that in mind.

FUNCTION {format.pages}
{ pages empty$
    { "" }
    { pages multi.page.check
        { "pages" pages n.dashify tie.or.space.connect }
        { "page" pages tie.or.space.connect }
      if$
    }
  if$
}

% The format.vol.num.pages function is for the volume, number, and
% page range of a journal article.  We use the format:
% vol(number):pages, with some variations for empty fields.  This
% doesn't begin a sentence.

FUNCTION {format.vol.num.pages}
{ volume empty$
    { number empty$
        { "" }
        { "no.~" number * }
      if$
      pages empty$
        'skip$
        { duplicate$ empty$
            { pop$ format.pages }
            { ":" * pages n.dashify * }
          if$
        }
      if$
    }
    { volume
      number empty$
        'skip$
        { "(" number * ")" * * }
      if$
      pages empty$
        'skip$
        { ":" * pages n.dashify * }
      if$
    }
  if$
}

%%  FUNCTION {format.vol.num.pages}
%%  { volume field.or.null
%%    number empty$
%%      'skip$
%%      { "(" number * ")" * *
%%        volume empty$
%%      { "there's a number but no volume in " cite$ * warning$ }
%%      'skip$
%%        if$
%%      }
%%    if$
%%    pages empty$
%%      'skip$
%%      { duplicate$ empty$
%%      { pop$ format.pages }
%%      { ":" * pages n.dashify * }
%%        if$
%%      }
%%    if$
%%  }


% The format.chapter.pages, if the chapter is present, puts whatever
% is in the type field (or else "chapter" if type is empty) in front
% of a chapter number.  It then appends the pages, if present.  This
% doesn't begin a sentence.

FUNCTION {format.chapter.pages}
{ chapter empty$
    'format.pages
    { type empty$
        { "chapter" }
        { type "l" change.case$ }
      if$
      chapter tie.or.space.connect
      pages empty$
        'skip$
        { ", " * format.pages * }
      if$
    }
  if$
}

% The format.in.ed.booktitle function is used for starting out a
% sentence that begins "In <booktitle>", putting an editor before the
% title if one exists.

FUNCTION {format.in.ed.booktitle}
{ booktitle empty$
    { "" }
    { editor empty$
        {
            "In "
            output.language.begin
            booktitle *
            emphasize *
        }
        {
            "In " format.editors * ", " *
            output.language.begin
            booktitle *
            emphasize *
        }
      if$
    }
  if$
}

% The function empty.misc.check complains if all six fields are empty,
% and if there's been no sorting or alphabetic-label complaint.

FUNCTION {empty.misc.check}
{ author empty$ title empty$ howpublished empty$
  month empty$ year empty$ note empty$
  and and and and and

  key empty$ not and

    { "all relevant fields are empty in " cite$ * warning$ }
    'skip$
  if$
}

% The function format.thesis.type returns either the (case-changed)
% type field, if it is defined, or else the default string already on
% the stack (like "Master's thesis" or "PhD thesis").

FUNCTION {format.thesis.type}
{ type empty$
    'skip$
    { pop$
      type "t" change.case$
    }
  if$
}

% The function format.tr.number makes a string starting with
% "Technical Report" (or type, if that field is defined), followed by
% the number if there is one; it returns the starting part (with a
% case change) even if there is no number.  This is used at the
% beginning of a sentence.

FUNCTION {format.tr.number}
{ type empty$
    { "Technical Report" }
    'type
  if$
  number empty$
    { "t" change.case$ }
    { number tie.or.space.connect }
  if$
}

FUNCTION {do.abstract}
{ abstract empty$
  'skip$
  { "\beginbibabs" write$
    newline$
    abstract write$
    newline$
    "\endbibabs" write$
    newline$ }
  if$
}

% Now we define the type functions for all entry types that may appear
% in the .BIB file---e.g., functions like `article' and `book'.  These
% are the routines that actually generate the .BBL-file output for the
% entry.  These must all precede the READ command.  In addition, the
% style designer should have a function `default.type' for unknown
% types.  Note: The fields (within each list) are listed in order of
% appearance, except as described for an `inbook' or a `proceedings'.
%
% The article function is for an article in a journal.  An article may
% CROSSREF another article.
%       Required fields: author, title, journal, year
%       Optional fields: volume, number, pages, month, note
%
% The book function is for a whole book.  A book may CROSSREF another
% book.
%    Required fields: author or editor, title, publisher, year
%    Optional fields: volume or number, series, address, edition,
%                     month, note
%
% The other entry functions are all quite similar, so no "comment
% version" will be given for them.

FUNCTION {article}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
  new.block
    output.language.begin
      journal * emphasize "journal" output.check
      format.vol.num.pages output
    new.block
    publisher output
    address output
  new.block
  format.language *
  note output
  fin.entry
  do.abstract
}

% A bachelorsthesis is a Bachelor's thesis. MIT
%       Required: author, title, school, year
%       Optional: type, address, month, note

FUNCTION {bachelorsthesis}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
  new.block
  "Bachelor's thesis" format.thesis.type output.nonnull
  school "school" output.check
  address output
  format.month output
  new.block
  note output
  fin.entry
  do.abstract
}

FUNCTION {do.book}
{ output.bibitem
  format.year %"year" output.check
  author empty$
    { format.editors "author and editor" output.check }
    { format.authors %output.nonnull
%         "author and editor" editor either.or.check
    }
  if$
  new.block
  format.btitle "title" output.check
      format.bvolume output
      new.block
      format.number.series output
      new.sentence
      publisher "publisher" output.check
      address output
  format.edition output
  format.month output
  new.block
  format.language *
  note output
  fin.entry
  do.abstract
}

FUNCTION {book}
{ crossrefonly missing$
   { do.book }
   { crossrefonly "1" =
      'skip$
      { do.book }
     if$
   }
  if$
}

%FUNCTION {book}
%{ crossrefonly missing$
%   { do.book }
%   { crossrefonly "1" =
%      { newline$
%        "\ifusecrossrefs " write$
%          do.book
%        "\fi " write$
%        newline$
%      }
%      { do.book }
%     if$
%   }
%  if$
%}

% A booklet is a bound thing without a publisher or sponsoring
% institution.
%   Required: title
%   Optional: author, howpublished, address, month, year, note

FUNCTION {booklet}
{ output.bibitem
  format.year %"year" output.check
  format.authors
  new.block
  format.title "title" output.check
  howpublished address new.block.checkb
  howpublished output
  address output
  format.month output
  new.block
  note output
  fin.entry
  do.abstract
}

% For the conference entry type, see inproceedings.

% An inbook is a piece of a book: either a chapter and/or a page
% range.  It may CROSSREF a book.  If there's no volume field, the
% type field will come before number and series.
%   Required: author or editor, title, chapter and/or pages,
%             publisher, year
%   Optional: volume or number, series, type, address, edition, month,
%             note

FUNCTION {inbook}
{ output.bibitem
  format.year %"year" output.check
  author empty$
    { format.editors "author and editor" output.check }
    { format.authors %output.nonnull
            %"author and editor" editor either.or.check
    }
  if$
  new.block
  format.btitle "title" output.check
      format.bvolume output
      format.chapter.pages "chapter and pages" output.check
      new.block
      format.number.series output
      new.sentence
      publisher "publisher" output.check
      address output
  format.edition output
  format.month output
  new.block
  format.language *
  note output
  fin.entry
  do.abstract
}

% An incollection is like inbook, but where there is a separate title
% for the referenced thing (and perhaps an editor for the whole).  An
% incollection may CROSSREF a book.
%   Required: author, title, booktitle, publisher, year
%   Optional: editor, volume or number, series, type, chapter, pages,
%             address, edition, month, note

FUNCTION {incollection}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
      new.block
      format.in.ed.booktitle "booktitle" output.check
      format.bvolume output
      format.number.series output
      format.chapter.pages output
      new.sentence
      publisher "publisher" output.check
      address output
      format.edition output
      format.month output
  new.block
  format.language *
  note output
  fin.entry
  do.abstract
}

% An inproceedings is an article in a conference proceedings, and it
% may CROSSREF a proceedings.  If there's no address field, the month
% (& year) will appear just before note.
%   Required: author, title, booktitle, year
%   Optional: editor, volume or number, series, pages, address, month,
%             organization, publisher, note

FUNCTION {inproceedings}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
      new.block
      format.in.ed.booktitle "booktitle" output.check
      format.bvolume output
      format.number.series output
      format.pages output
      address empty$
        { organization publisher new.sentence.checkb
          organization output
          publisher output
          format.month output
        }
        { address output.nonnull
          format.month output
          new.sentence
          organization output
          publisher output
        }
      if$
  new.block
  format.language *
  note output
  fin.entry
  do.abstract
}

% The conference function is included for Scribe compatibility.

FUNCTION {conference} { inproceedings }

% A manual is technical documentation.
%       Required: title
%       Optional: author, organization, address, edition, month, year,
%                 note

FUNCTION {manual}
{ output.bibitem
  format.year %"year" output.check
  author empty$
    { organization empty$
        'skip$
        { organization output.nonnull
          address output
        }
      if$
    }
    { format.authors output.nonnull }
  if$
  new.block
  format.btitle "title" output.check
  author empty$
    { organization empty$
        { address new.block.checka
          address output
        }
        'skip$
      if$
    }
    { organization address new.block.checkb
      organization output
      address output
    }
  if$
  format.edition output
  format.month output
  new.block
  note output
  fin.entry
  do.abstract
}

% A mastersthesis is a Master's thesis.
%       Required: author, title, school, year
%       Optional: type, address, month, note

FUNCTION {mastersthesis}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
  new.block
  "Master's thesis" format.thesis.type output.nonnull
  school "school" output.check
  address output
  format.month output
  new.block
  note output
  fin.entry
  do.abstract
}

% A misc is something that doesn't fit elsewhere.
%       Required: at least one of the `optional' fields
%       Optional: author, title, howpublished, month, year, note

FUNCTION {misc}
{ output.bibitem
  format.year %"year" output.check
  format.authors
  title howpublished new.block.checkb
  format.title output
  howpublished new.block.checka
  howpublished output
  format.month output
  new.block
  format.language *
  note output
  fin.entry
  do.abstract
  empty.misc.check
}

% A phdthesis is like a mastersthesis.
%       Required: author, title, school, year
%       Optional: type, address, month, note

FUNCTION {phdthesis}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.btitle "title" output.check
  new.block
  "PhD thesis" format.thesis.type output.nonnull
  school "school" output.check
  address output
  format.month output
  new.block
  note output
  fin.entry
  do.abstract
}

% A proceedings is a conference proceedings.  If there is an
% organization but no editor field, the organization will appear as
% the first optional field (we try to make the first block nonempty);
% if there's no address field, the month (& year) will appear just
% before note.
%   Required: title, year
%   Optional: editor, volume or number, series, address, month,
%             organization, publisher, note

FUNCTION {do.proceedings}
{ output.bibitem
  editor empty$
    { organization output }
    { format.editors output.nonnull }
  if$
  format.year %"year" output
  new.block
  format.btitle "title" output.check
  format.bvolume output
  format.number.series output
  address empty$
    { editor empty$
        { publisher new.sentence.checka }
        { organization publisher new.sentence.checkb
          organization output
        }
      if$
      publisher output
      format.month output
    }
    { address output.nonnull
      format.month output
      new.sentence
      editor empty$
        'skip$
        { organization output }
      if$
      publisher output
    }
  if$
  new.block
  note output
  fin.entry
  do.abstract
}

FUNCTION {proceedings}
{ crossrefonly missing$
   { do.proceedings }
   { crossrefonly "1" =
      'skip$
      { do.proceedings }
     if$
   }
  if$
}

% A techreport is a technical report.
%       Required: author, title, institution, year
%       Optional: type, number, address, month, note

FUNCTION {techreport}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
  new.block
  format.tr.number output.nonnull
  institution "institution" output.check
  address output
  format.month output
  new.block
  note output
  fin.entry
  do.abstract
}

% An unpublished is something that hasn't been published.
%       Required: author, title, note
%       Optional: month, year

FUNCTION {unpublished}
{ output.bibitem
  format.year %"year" output.check
  format.authors %"author" output.check
  new.block
  format.title "title" output.check
  new.block
  note "note" output.check
  format.month output
  fin.entry
  do.abstract
}

% We use entry type `misc' for an unknown type; BibTeX gives a
% warning.

FUNCTION {default.type} { misc }

% Here are macros for common things that may vary from style to style.
% Users are encouraged to use these macros.
%
% Months are written out in full

MACRO {jan} {"January"}

MACRO {feb} {"February"}

MACRO {mar} {"March"}

MACRO {apr} {"April"}

MACRO {may} {"May"}

MACRO {jun} {"June"}

MACRO {jul} {"July"}

MACRO {aug} {"August"}

MACRO {sep} {"September"}

MACRO {oct} {"October"}

MACRO {nov} {"November"}

MACRO {dec} {"December"}

% Journals are written out in full
%
% To get a completely different set of abbreviations, it may be best
% to make a separate .bib file with nothing but those abbreviations;
% users could then include that file name as the first argument to the
% \bibliography command

MACRO {aal} {"Algebra and Logic"}

MACRO {aam} {"Advances in Applied Mathematics"}

MACRO {acmcs} {"ACM Computing Surveys"}

MACRO {acta} {"Acta Informatica"}

MACRO {ai} {"Artificial Intelligence"}

MACRO {ail} {"Algebra i Logika"}

MACRO {algolb} {"ALGOL Bulletin"}

MACRO {algor} {"Algorithmica"}

MACRO {ama} {"Advances in Mathematics"}

MACRO {apal} {"Annals of Pure and Applied Logic"}

MACRO {archiv} {"Archiv Math. Logik Grundlagenforsch"}

MACRO {cacm} {"Communications of the ACM"}

MACRO {cee} {"Computers and Electrical Engineering"}

MACRO {cmu} {"Carnegie-Mellon University"}

MACRO {cma} {"Computers and Mathematics with Applications"}

MACRO {comb} {"Combinatorica"}

MACRO {comj} {"Computer Journal"}

MACRO {comlan} {"Computer Languages"}

MACRO {comnet} {"Computer Networks"}

MACRO {cwi} {"Centrum voor Wiskunde en Informatica"}

MACRO {discomgeom} {"Discrete and Computational Geometry"}

MACRO {discomp} {"Distributed Computing"}

MACRO {eatcs} {"Bulletin of the European Association for Theoretical Computer Science"}

MACRO {i&comp} {"Information and Computation"}

MACRO {iandcomp} {"Information and Computation"}

MACRO {i&c} {"Information and Computation"}

MACRO {iandc} {"Information and Control"}

MACRO {ibmjrd} {"IBM Journal of Research and Development"}

MACRO {ibmsj} {"IBM Systems Journal"}

MACRO {icalp} {"International Colloquium on Automata, Languages, and Programming"}

MACRO {ieeeit} {"IEEE Transactions on Information Theory"}

MACRO {ieeese} {"IEEE Transactions on Software Engineering"}

MACRO {ieeetc} {"IEEE Transactions on Computers"}

MACRO {ieeetcad}
 {"IEEE Transactions on Computer-Aided Design of Integrated Circuits"}

MACRO {ieeetpami} {"IEEE Transactions on Pattern Analysis and Machine Intelligence"}

MACRO {ijpp} {"International Journal of Parallel Programming"}

MACRO {ipl} {"Information Processing Letters"}

MACRO {jacm} {"Journal of the ACM"}

MACRO {jalg} {"Journal of Algorithms"}

MACRO {jcss} {"Journal of Computer and System Sciences"}

MACRO {jir} {"Journal of Irreproducible Results"}

MACRO {jpdc} {"Journal of Parallel and Distributed Computing"}

MACRO {jsc} {"Journal of Symbolic Computation"}

MACRO {jsl} {"Journal of Symbolic Logic"}

MACRO {jvlsics} {"Journal of VLSI and Computer Systems"}

MACRO {lics} {"Logic in Computer Science"}

MACRO {lncs} {"Lecture Notes in Computer Science"}

MACRO {lnmath} {"Lecture Notes in Mathematics"}

MACRO {mathprog} {"Mathematical Programming"}

MACRO {mit} {"Mass\-a\-chu\-setts Insti\-tute of Tech\-no\-logy"}

MACRO {mitai} {"MIT Artificial Intelligence Laboratory"}

MACRO {miteecs} {"Department of Electrical Engineering and Computer Science, Mass\-a\-chu\-setts Insti\-tute of Tech\-no\-logy"}

MACRO {mitlcs} {"MIT Laboratory for Computer Science"}

MACRO {mitmath} {"Department of Mathematics, Mass\-a\-chu\-setts Insti\-tute of Tech\-no\-logy"}

MACRO {mitp} {"MIT Press"}

MACRO {mor} {"Mathematics of Operations Research"}

MACRO {mst} {"Mathematical Systems Theory"}

MACRO {networks} {"Networks"}

MACRO {or} {"Operations Research"}

MACRO {orl} {"Operations Research Letters"}

MACRO {pieee} {"Proceedings of the IEEE"}

MACRO {popl} {"Principles of Programming Languages"}

MACRO {prentice} {"Prentice-Hall, Inc."}

MACRO {scp} {"Science of Computer Programming"}

MACRO {sicomp} {"SIAM Journal on Computing"}

MACRO {siamjdm} {"SIAM Journal on Discrete Mathematics"}

MACRO {siamr} {"SIAM Review"}

MACRO {sigplan} {"ACM SIGPLAN Notices"}

MACRO {slfm} {"Studies in Logic and the Foundations of Mathematics"}

MACRO {sp&e} {"Software: Practice \& Experience"}

MACRO {spande} {"Software: Practice \& Experience"}

MACRO {tcs} {"Theoretical Computer Science"}

MACRO {tocs} {"ACM Transactions on Computer Systems"}

MACRO {tods} {"ACM Transactions on Database Systems"}

MACRO {tog} {"ACM Transactions on Graphics"}

MACRO {toms} {"ACM Transactions on Mathematical Software"}

MACRO {toois} {"ACM Transactions on Office Information Systems"}

MACRO {toplas} {"ACM Transactions on Programming Languages and Systems"}

MACRO {utm} {"Undergraduate Texts in Mathematics"}

MACRO   {zmlgm} {"Zeitschrift f\accent'177 ur Mathematische Logik und Grundlagen der Mathematik"}

% Now we read in the .BIB entries.

READ

% The sortify function converts to lower case after purify$ing; it's
% used in sorting and in computing alphabetic labels after sorting
%
% The chop.word(w,len,s) function returns either s or, if the first
% len letters of s equals w (this comparison is done in the third line
% of the function's definition), it returns that part of s after w.

FUNCTION {sortify}
{ purify$
  "l" change.case$
}

INTEGERS { len }

FUNCTION {chop.word}
{ 's :=
  'len :=
  s #1 len substring$ =
    { s len #1 + global.max$ substring$ }
    's
  if$
}

% When sorting, we compute the sortkey by executing "presort" on each
% entry.  The presort key contains a number of "sortify"ed strings,
% concatenated with multiple blanks between them.  This makes things
% like "brinch per" come before "brinch hansen per".
%
% The fields used here are: the sort.label for alphabetic labels (as
% set by calc.label), followed by the author names (or editor names or
% organization (with a leading "The " removed) or key field, depending
% on entry type and on what's empty), followed by year, followed by
% the first bit of the title (chopping off a leading "The ", "A ", or
% "An ").
%
% Names are formatted as: Von Last First Junior.
%
% The names within a part will be separated by a single blank (such as
% "brinch hansen"), two will separate the name parts themselves
% (except the von and last), three will separate the names, four will
% separate the names from year (and from label, if alphabetic), and
% four will separate year from title.
%
% The sort.format.names function takes an argument that should be in
% BibTeX name format, and returns a string containing " "-separated
% names in the format described above.  The function is almost the
% same as format.names.

FUNCTION {sort.format.names}
{ 's :=
  #1 'nameptr :=
  ""
  s num.names$ 'numnames :=
  numnames 'namesleft :=
    { namesleft #0 > }
    { nameptr #1 >
        { "   " * }
        'skip$
      if$
      s nameptr "{vv{ } }{ll{ }}{  ff{ }}{  jj{ }}" format.name$ 't :=
      nameptr numnames = t "others" = and
        { "et al" * }
        { t sortify * }
      if$
      nameptr #1 + 'nameptr :=
      namesleft #1 - 'namesleft :=
    }
  while$
}

% The sort.format.title function returns the argument, but first any
% leading "A "'s, "An "'s, or "The "'s are removed.  The chop.word
% function uses s, so we need another string variable, t

FUNCTION {sort.format.title}
{ 't :=
  "A " #2
    "An " #3
      "The " #4 t chop.word
    chop.word
  chop.word
  sortify
  #1 global.max$ substring$
}

% The auxiliary functions here, for the presort function, are
% analogous to the ones for calc.label; the same comments apply,
% except that the organization field takes precedence here over the
% key field.  For sorting purposes, we still remove a leading "The "
% from the organization field.

FUNCTION {author.sort}
{ sort-author empty$
    { author empty$
        { key empty$
            { "to sort, need author or key in " cite$ * warning$
              ""
            }
            { key sortify }
          if$
        }
        { author sort.format.names }
      if$
    }
    { sort-author sort.format.names }
  if$
}

FUNCTION {author.editor.sort}
{ sort-author empty$
    { author empty$
        { editor empty$
            { key empty$
                { "to sort, need author, editor, or key in "
                  cite$ * warning$
                  ""
                }
                { key sortify }
              if$
            }
            { editor sort.format.names }
          if$
        }
        { author sort.format.names }
      if$
    }
    { sort-author sort.format.names }
  if$
}

FUNCTION {author.organization.sort}
{ sort-author empty$
  { author empty$
     { organization empty$
        { key empty$
           { "to sort, need author, organization, or key in "
              cite$ * warning$
               ""
            }
             { key sortify }
           if$
         }
         { "The " #4 organization chop.word sortify }
       if$
     }
     { author sort.format.names }
    if$
  }
  { sort-author sort.format.names }
  if$
}

FUNCTION {editor.organization.sort}
{ editor empty$
    { organization empty$
        { key empty$
            { "to sort, need editor, organization, or key in "
              cite$ * warning$
              ""
            }
            { key sortify }
          if$
        }
        { "The " #4 organization chop.word sortify }
      if$
    }
    { editor sort.format.names }
  if$
}

% There is a limit, entry.max$, on the length of an entry string
% variable (which is what its sort.key$ is), so we take at most that
% many characters of the constructed key, and hope there aren't many
% references that match to that many characters!

FUNCTION {presort}
{
  sortgroup field.or.null
  "      "
  *
  #1 #8 substring$
  sortkey empty$
  {
  type$ "book" =
  type$ "inbook" =
  or
    'author.editor.sort
    { type$ "proceedings" =
        'editor.organization.sort
        { type$ "manual" =
            'author.organization.sort
            'author.sort
          if$
        }
      if$
    }
  if$
  }
  { sortkey sortify }
  if$
  *
  "    "
  *
  year field.or.null sortify
  *
  subyear empty$
    'skip$
    { subyear * }
  if$
  "    "
  *
  title field.or.null
  sort.format.title
  *
  #1 entry.max$ substring$
  'sort.key$ :=
}

ITERATE {presort}

% And now we can sort

SORT

%% % Now comes the computation for numeric labels.
%% % We use either the sorted order or original order.
%% % We still have to keep track of the longest (in width$ terms)
%% % label, for use by the "thebibliography" environment.
%%
%% STRINGS { longest.label }
%%
%% INTEGERS { number.label longest.label.width }
%%
%% FUNCTION {initialize.longest.label}
%% { "" 'longest.label :=
%%   #1 'number.label :=
%%   #0 'longest.label.width :=
%% }
%%
%% FUNCTION {longest.label.pass}
%% { number.label int.to.str$ 'label :=
%%   number.label #1 + 'number.label :=
%%   label width$ longest.label.width >
%%     { label 'longest.label :=
%%       label width$ 'longest.label.width :=
%%     }
%%     'skip$
%%   if$
%% }
%%
%% EXECUTE {initialize.longest.label}
%%
%% ITERATE {longest.label.pass}

STRINGS { prev.author }

FUNCTION {initialize.prev.author}
{ "abcxyz" 'prev.author := }

FUNCTION {do.fix.authors}
{
    sort-author empty$
        { author purify$ prev.author =
            {   "\bysame" 'extra.label := }
            {
                "" 'extra.label :=
                author purify$ 'prev.author :=
            }
          if$
        }
        { sort-author purify$ prev.author =
            { "\bysame" 'extra.label := }
            { "" 'extra.label :=
              sort-author purify$ 'prev.author :=
            }
          if$
        }
    if$
}

FUNCTION {fix.authors}
{
    crossrefonly missing$
        'do.fix.authors
        { type$ "proceedings" =
          crossrefonly "1" =
          and
            'skip$
            'do.fix.authors
          if$
        }
    if$
}

EXECUTE {initialize.prev.author}

ITERATE {fix.authors}

FUNCTION {longest.label}
{ "00" }

% Now we're ready to start writing the .BBL file.  We begin, if
% necessary, with a LaTeX macro for unnamed names in an alphabetic
% label; next comes stuff from the `preamble' command in the database
% files.  Then we give an incantation containing the command
%     \begin{thebibliography}{...}
% where the `...' is the longest label.
%
% We also call init.state.consts, for use by the output routines.

FUNCTION {begin.bib}
{ preamble$ empty$
    'skip$
    { preamble$ write$ newline$ }
  if$
  "\begin{thebibliography}" write$ newline$
    #0 'beginning :=
}

EXECUTE {begin.bib}

EXECUTE {init.state.consts}

% Now we produce the output for all the entries

ITERATE {call.type$}

% Finally, we finish up by writing the `\end{thebibliography}' command.

FUNCTION {end.bib}
{
    newline$
    "\end{paperlist}" write$ newline$
    newline$
    "\end{thebibliography}" write$ newline$
}

EXECUTE {end.bib}