\documentstyle[12pt]{report}
  \nofiles                          
  \def\LATEX{\LaTeX}
  \let\TEX = \TeX               
  \setcounter{totalnumber}{5}   
  \setcounter{topnumber}{3}     
  \setcounter{bottomnumber}{3}
  \setlength{\oddsidemargin}{3.9cm}     %real measurement 1.5in
  \setlength{\textwidth}{5.7in}         %right margin is now 1in
  \setlength{\topmargin}{1cm}
  \setlength{\headheight}{.6cm}
  \setlength{\textheight}{8.5in}
  \setlength{\parindent}{1cm}
  \renewcommand{\baselinestretch}{1.5}
  \raggedbottom
  \setlength{\itemsep}{-2mm}
  \input{init.tex}
  \input{fparts.tex}
  \input{cto.tex}
  \input{bonds.tex}
  \begin {document}    
  \setcounter{page}{70}
  \setcounter{chapter}{6}
  \textfont1=\tenrm
  \initial
  \newcommand{\rhq}{An argument of ``Q'' causes no action. \ }
  \newcommand{\ri}{All other argument values cause no action. }
 \len=4
  
 \vspace{\len mm}
 \noindent D. \underline{General Utility Macros}

 \vspace{\len mm}
 \indent i. \underline{Macro $\backslash $fuseiv[9]}.
 \ This macro typesets a fragment that is designed to be
 connected at two places to another ring system with the
 effect of fusing an additional sixring to that system.
 The fragment can be fused to positions 1 and 2 of the
 carbon fivering and the carbon sixring, and to positions
 2 and 3 of the \verb+\+hetifive and \verb+\+hetisix rings
 without changing
 the unitlength and the \verb+\+yi coordinate.
 \yi=200  \pht=750

 \[ \fuseiv{$R^1$}{$R^2$}{$R^3$}{$R^4$}{D}{$R^6$}{Q}{Q}{D} \]

 \reinit
 \begin{description}
 \item[{\rm \ \ \ \ \ \ Arguments 1 -- 4:}]  \rhq  All other argument
 values are used as the substituent formulas ${\rm R^1}$ --
 ${\rm R^4}$.
 \item[{\rm \ \ \ \ \ \ Argument 5:}]  An argument of ``D''
      prints a second bond between the upper point of 
      attachment and position 1 (this double bond is shown
      in the diagram). \ri
 \item[{\rm \ \ \ \ \ \ Argument 6:}] \rhq  An argument of ``D'' prints
      a second bond between positions 1 and 2. All other argument
      values are used as the substituent formula ${\rm R^6}$.
 \item[{\rm \ \ \ \ \ \ Argument 7:}]  An argument of ``D''
      prints a second bond between positions 2 and 3. All other
      argument values cause no action.
 \item[{\rm \ \ \ \ \ \ Argument 8:}] \rhq  An argument of ``D'' prints
      a second bond between positions 3 and 4.  All other 
      argument values are used as a second substituent in
      position 3 (not shown in the diagram).
 \item[{\rm \ \ \ \ \ \ Argument 9:}] An argument of ``D'' prints
      a second bond from the lower point of attachment to
      position 4 (this double bond is shown in the diagram).
      All other argument values cause no action.
 \end{description}
 \newpage
 \indent ii. \underline{Macro $\backslash $fuseup[9]}.
 \ This macro typesets a fragment that is designed to be
 connected at two places to another ring system with the
 effect of fusing an additional sixring to that system
 at an angle. The fragment can be fused to positions 
 1 and 6 of the carbon sixring and positions 3 and 4 of
 the \verb+\+hetisix rings without changing the unitlength
 and the \verb+\+yi coordinate.
 \advance \yi by -500 

 \[ \fuseup{$R^1$}{$R^2$}{$R^3$}{$R^4$}{D}{Q}{D}{Q}{D} \]

 \yi=300
 \begin{description}
 \item[{\rm \ \ \ \ \ \ Arguments 1 -- 4:}] \rhq  All other
      argument values are used as the respective substituent
      formulas ${\rm R^1}$ -- ${\rm R^4}$.
 \item[{\rm \ \ \ \ \ \ Argument 5:}] An argument of ``D'' prints
      a second bond from the upper point of attachment to
      position 1 (the resulting double bond is shown in the
      diagram). \ri    
 \item[{\rm \ \ \ \ \ \ Argument 6:}] An argument of ``D'' prints
      a second bond between positions 1 and 2. \ri  
 \item[{\rm \ \ \ \ \ \ Argument 7:}] An argument of ``D'' prints
      a second bond between positions 2 and 3 (the resulting 
      double bond is shown in the diagram). \ri 
 \item[{\rm \ \ \ \ \ \ Argument 8:}] An argument of ``D'' prints 
      a second bond between positions 3 and 4. \ri 
 \item[{\rm \ \ \ \ \ \ Argument 9:}] An argument of ``D'' prints
      a second bond between position 4 and the lower point
      of attachment (the resulting double bond is shown in
      the diagram). \ri 
 \end{description}
 \newpage
 \indent iii. \underline{Macro $\backslash $fuseiii[6]}.
 \ This macro typesets a fragment that is designed to be
 connected at two places to another ring system with the
 effect of fusing an additional fivering to that system.
 The fragment can be fused to positions 1 and 2 of the
 carbon fivering and sixring, and to positions 2 and 3 of
 the \verb+\+hetifive and \verb+\+hetisix rings  
 without changing the unitlength and the \verb+\+yi
 coordinate.
 \pht=600

 \[ \fuseiii{$R^1$}{$R^2$}{$R^3$}{$R^4$}{Q}{D}   \]

 \begin{description}
 \item[{\rm \ \ \ \ \ \ Arguments 1 -- 4:}] \rhq  All other
      arguments are used as the respective substituent
      formulas ${\rm R^1}$ -- ${\rm R^4}$.
 \item[{\rm \ \ \ \ \ \ Argument 5:}] \rhq  All other argument
      values are used as a second substituent in position~2
      (not shown in the diagram).
 \item[{\rm \ \ \ \ \ \ Argument 6:}] An argument of ``D''
      prints a second bond between positions 1 and 2. \ri 
 \end{description}

 \vspace{\len mm}
 \indent iv. \underline{Macro $\backslash $cto[3]}.
 \ This macro draws a reaction arrow and puts the requested
 character strings representing reagents and reaction
 conditions on top and below the arrow, respectively.
 The arrow is made long enough to accommodate the longer
 of the strings. The vertical position of the arrow can be
 changed by changing the \verb+\+yi value.
 \pw=1500

 \[ \cto{string\  on\  top\  of\  the\  arrow}{string\  below}{26} \]

 \begin{description}
 \item[{\rm \ \ \ \ \ \ Arguments 1 and 2:}] The character 
      strings above and below the arrow, respectively.
 \item[{\rm \ \ \ \ \ \ Argument 3:}] An integer, the number of characters -- 
      including subscripts -- in the longer string.
 \end{description}
 
 \vspace{\len mm}
 \indent v. \underline{Macro $\backslash $sbond[1]}.
 \ This macro draws a horizontal single bond of a specified
 length, vertically centered on a line. It should be used
 for structural formulas that do not use the picture
 environment and are written on one line.

 \[ \sbond{20}  \]

 The argument is an integer, expressing the length of the
 bond in printer points (1 pt = .35 mm).
 
 \vspace{\len mm}
 \indent vi. \underline{Macro $\backslash $dbond[2]}.
 \  This macro draws a horizontal double bond of a
 specified length. It should be used for structural
 formulas that do not use the picture environment and
 are written on one line.

 \[ \dbond{20}{19}  \]

 \begin{description}
 \item[{\rm \ \ \ \ \ \ Argument 1:}] An integer, expressing
      the length of the bond in printer points.
 \item[{\rm \ \ \ \ \ \ Argument 2:}] An integer, expressing
      the amount of vertical space by which the bonds have
      to be pushed together to give the desired vertical
      distance. In a document with double spacing, the
      number 19 produced the spacing in the double bond
      shown above. 
 \end{description}

 \vspace{\len mm}
 \indent vii. \underline{Macro $\backslash $tbond[2]}.
 \ This macro is similar to \verb+\+dbond, except that it
 draws a triple bond:

 \[ \tbond{20}{20}  \]

 The meaning of the arguments is the same as in 
 \verb+\+dbond. The number 20 was used as argument 2.
 \vspace{\len mm}
  

 \centerline{3. COMMON REQUIREMENTS FOR THE USE OF THE SYSTEM}
 \vspace{\len mm}
 So far in this thesis it has been explained how to write
 LaTeX code to produce a chemical structure diagram at a
 particular place in a document. This section will discuss the
 mandatory and the optional statements at the beginning of an
 input file that make the system of macros accessible and
 its use more practical and convenient. Figure 6.1 contains
 these statements together with the two required declarations
 at the beginning of a LaTeX file, lines (1) and (9).
 (The line numbers are for reference only, they are not used
 in the input file.)

 The part of the input file preceding the \verb+\+begin\{document\}
 statement is called the ``preamble'' in the LaTeX Manual.
 In addition to the statements shown here, the preamble usually
 contains declarations pertaining to text formatting details
 such as margin width, text height on a page, and space between
 lines. 

 The statement in line (2) of figure 6.1 is necessary if the
 structure-drawing macros of this thesis are to be used for
 the preparation of a document. This statement reads the file
 init.tex into TeX's memory, a file that contains two short
 macros, \verb+\+initial and \verb+\+reinit. Macro \verb+\+initial
 defines the command sequences \verb+\+xi, \verb+\+yi, \verb+\+pw,
 \verb+\+pht, \verb+\+xbox, and \verb+\+len  as integer variables
 and assigns a count register to each of them.  The use of the
 first four variables in the picture declaration and the use
 of \verb+\+xbox in a minipage or parbox environment was
 explained in chapter III. The counter \verb+\+len is a general
 purpose integer variable for the user. All the variables
 except \verb+\+len are also given initial values. ---
 Furthermore, the unitlength for the picture environments is
 set to 0.1 printer points in \verb+\+initial. This is the
 recommended unitlength for the chemical structure diagrams,
 but it can be changed anywhere in the document. ---
 Line (11) from figure 6.1 expands \verb+\+initial. 

 The macro \verb+\+reinit simply resets all the parameters
 to their initial values from \verb+\+initial. It is a
 convenience, especially for cases where more than one
 variable needs to be reset.

 \begin{figure}\centering
  \begin{minipage}{8cm}
  \begin{verbatim}
   (1)  \documentstyle[12pt]{report}
   (2)  \input{init.tex}
   (3)  \input{rings1.tex}
   (4)  \setcounter{totalnumber}{4}
   (5)  \setcounter{topnumber{2}
   (6)  \setcounter{bottomnumber}{2}
   (7)  \renewcommand{\topfraction}{.5}
   (8)  \renewcommand{\bottomfraction}{.5}
   (9)  \begin{document}
   (10) \textfont1=\tenrm
   (11) \initial
  \end{verbatim}
  \end{minipage}
  \caption{Statements at the beginning of a LaTeX file}
 \end{figure}
 
 The statement in line (3) of figure 6.1  reads a file                      
 with structure-drawing macros. There will usually be
 several such statements, reading in different macros or
 sets of macros. At the installation where this work was
 done the TeX memory is not large enough to read in all
 the chemistry macros. TeX's own macros already take up
 13\% of the reserved memory and when the LaTeX macros are
 added, two thirds of the memory are used before an
 input file is processed. --- Reading in just part of the 
 structure-drawing macros for any given document has the
 advantage of saving processing time.
 
 Lines (4) -- (8) in figure 6.1 affect the placement of
 ``floats'' on the page. The only floats discussed in this
 thesis are the diagrams produced in the figure
 environment (see chapter III). In defining the style
 of a document -- the report style is designated by line (1) -- 
 the LaTeX program sets default values for the maximum
 total number of floats on a page (three), the maximum
 number of floats at the top of the page (two), and at
 the bottom of the page (one). These values can be 
 changed for documents with an unusually large number
 of figures. Thus, lines (4) -- (6) increase the 
 maximum number of floats to 4, evenly distributed on
 the page. It is then necessary to change the counters
 \verb+\+topfraction and \verb+\+bottomfraction to
 reflect the distribution of figures on the page.

 Finally, line(10) is the optional redefinition of the
 math textfont, discussed in chapter III. This definition
 can be changed anywhere in the document.

  \end{document}