Entire document typed in monospace font

Question

I want to put an entire document into monospace font for various reasons. This is nominally fairly easy; you can say \renewcommand{\familydefault}{\ttdefault}. However, there at least two problems with this approach (and possibly more). Thus, my question is really three separate ones:

1. So far, I'm having a problem with the spaces not working as they should; this seems to be fixed by \obeyspaces, but I am unsure of how well this really works. The only references to it I could find were on this site, and they didn't really explain that command well. Could you please provide a reference for this or at least explain what the command does and what its limitations are?
2. My other problem is that sometimes LaTeX generates symbols (such as smart quotes), and these do not obey the monotype spacing. LaTeX even seems to generate these when the symbols are in the font used. Is there any way of finding out when this happens, and preferrably of telling LaTeX to use existing characters when possible? Update: This is not a problem at all; see below.
3. I have found these by myself, but it seems quite likely that there are other problems as well. Are there other things I should look out for, like accented characters? Bold seems to work correctly (at least in the Courier font), but will all such formatting?

Update: In case it is relevant (which, now that I think of it, it almost certainly is), I am using XeTeX and fontspec. I would prefer to keep this setup, but would be open to not using fontspec or to using pdflatex instead.

Update 2: The "smart quotes" problem was actually a problem with spaces after punctuation. I turned on French spacing, but this just emphasizes the need for part three of my question.

Answer 1

The easiest (but not the most flexible) way is to use memoir with the ms option. Then you get something that look like a good, old typewriter manuscript.

memoir also hard code the monospace font to be cmtt, se line 12643 in the memoir.cls. If you want another monospaced font, you need to change at least the lines:

\renewcommand{\familydefault}{cmtt}
\renewcommand{\rmdefault}{cmtt}
\renewcommand{\sfdefault}{cmtt}
\renewcommand{\bfdefault}{m}
\renewcommand{\itdefault}{n}
\renewcommand{\sldefault}{n}
\renewcommand{\scdefault}{n} 

Changing to scaled luximono:

\usepackage[scaled=0.85]{luximono}
\input{glyphtounicode}
\pdfgentounicode=1
\renewcommand{\familydefault}{ul9}
\renewcommand{\rmdefault}{ul9}
\renewcommand{\sfdefault}{ul9}
\renewcommand{\bfdefault}{m}
\renewcommand{\itdefault}{n}
\renewcommand{\sldefault}{n}
\renewcommand{\scdefault}{n}

I also recommend the package csquotes to ensure correct quoting marks.

EDIT: I forgot that you preferred XeLaTeX and it sems that memoir and the ms-option does not work with XeLaTeX.

Here is a new (near) MWE:

\documentclass[english,ms,11pt]{memoir}
  \usepackage{babel}
  \usepackage[T1]{fontenc}
  \usepackage[utf8]{inputenx}

  \usepackage{lmodern}
% Comment the line above and uncomment the following
% ten line to change monotype font.

%\usepackage[scaled=0.85]{luximono}
%\input{glyphtounicode}
%\pdfgentounicode=1
%\renewcommand{\familydefault}{ul9}
%\renewcommand{\rmdefault}{ul9}
%\renewcommand{\sfdefault}{ul9}
%\renewcommand{\bfdefault}{m}
%\renewcommand{\itdefault}{n}
%\renewcommand{\sldefault}{n}
%\renewcommand{\scdefault}{n}

\usepackage[autostyle=true]{csquotes} 
\usepackage{lipsum,kantlipsum} 

\begin{document}

\lipsum[2]

\end{document}

Computer Modern

Scaled Luximono

Answer 2

Monospaced fonts in the "old TeX world" usually don't allow for stretching and shrinking spaces. Here's the beginning of cmtt10.pl, which is the human readable version of the metric file cmtt10.tfm:

(FAMILY CMTT)
(FACE O 352)
(CODINGSCHEME TEX TYPEWRITER TEXT)
(DESIGNSIZE R 10.0)
(COMMENT DESIGNSIZE IS IN POINTS)
(COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)
(CHECKSUM O 33772436170)
(FONTDIMEN
   (SLANT R 0.0)
   (SPACE R 0.524996)
   (STRETCH R 0.0)
   (SHRINK R 0.0)
   (XHEIGHT R 0.430555)
   (QUAD R 1.049991)
   (EXTRASPACE R 0.524996)
   )

Similarly for pcrr8t.pl (used when \fontfamily{pcr} is selected, that is, Courier):

(FAMILY UNSPECIFIED)
(FACE F MRR)
(CODINGSCHEME EXTENDED TEX FONT ENCODING - LATIN)
(DESIGNSIZE R 10.0)
(COMMENT DESIGNSIZE IS IN POINTS)
(COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)
(CHECKSUM O 2142215632)
(FONTDIMEN
   (SLANT R 0.0)
   (SPACE R 0.6)
   (STRETCH R 0.0)
   (SHRINK R 0.0)
   (XHEIGHT R 0.425989)
   (QUAD R 1.0)
   (EXTRASPACE R 0.6)
   (PARAMETER D 8 R 0.562)
   (PARAMETER D 9 R 0.628992)
   (PARAMETER D 10 R 0.75299)
   (PARAMETER D 11 R 0.156995)
   (PARAMETER D 12 R 0.804993)
   (PARAMETER D 13 R 0.25)
   (PARAMETER D 14 R 0.6)
   (PARAMETER D 15 R 0.0)
   (PARAMETER D 16 R 1.2)
   )

Thus some input such as

\setbox0=\hbox spread 3pt{\ttfamily abc def}

(which is a miniature example of how TeX does justification stretching or shrinking interword spaces) results in the message

Underfull \hbox (badness 10000)

because there's no stretching in the spaces when \ttfamily is in force.

The situation is completely different in XeTeX, since the monospaced fonts I checked do allow for interword space stretching and shrinking: Latin Modern Mono, TeX Gyre Cursor, Courier. Let's make a comparison at the standard 10pt size

• TeX Gyre Cursor: 6pt plus 3pt minus 2pt
• Latin Modern Mono: 5.25pt plus 2.625pt minus 1.75pt
• Courier: 6.00096pt plus 3.00047pt minus 2.00032pt
• CMU Typewriter Text: 5.25pt plus 2.625pt minus 1.75pt

The data tell the normal width of the interword space and the amount of stretching and shrinking available.

Let's do a comparison, compiling the following document first with pdflatex and then with xelatex

\documentclass[draft]{article}
\usepackage{ifxetex}
\ifxetex
  \usepackage{fontspec}
  \setmonofont{Latin Modern Mono}
\else
  \usepackage{lmodern}
\fi
\usepackage{lipsum}
\textwidth=10cm
\begin{document}
\ttfamily
\noindent\lipsum[2]
\end{document}

Here's the result with pdflatex

Here's the result with xelatex

(The different size is due to how the images have been produced, they are just the same size in print.)

We can notice a big difference. In the first case the engine isn't able to do proper justification, in the second image the text appears justified and hyphenated.

Conclusion

If you need to reproduce a document prepared with a typewriter, the setup

\documentclass{article}

\usepackage{fontspec}
\usepackage{ragged2e}
\setmainfont[Ligatures=TeX]{Latin Modern Mono}% choose another one if you prefer

\begin{document}
% Uncomment the following line for standard spaces after periods
%\frenchspacing
% Uncomment the following line for ragged right setup
%\setlength{\RaggedRightRightskip}{0pt plus 4em}\RaggedRight

with XeLaTeX seems the best option.

Here's the result when applying both \frenchspacing and \RaggedRight: