Text Formatting ⇒ Macro Fail

[LaTexLearner]

I think there is something very basic I am missing about macros.

I need to learn how to make answer spaces for my worksheets. So far I've used:

Code: Select all

\underline{\hspace{0.8cm}}

This works OK.

But, of course, I want all of my answer spaces to be uniform and I need to learn macros. I made this macro, but it didn't quite work.

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\newcommand{\answerspace}[1]{\underline{\hspace{#1}}
\answerspace{3cm}

The error said my argument definition was not good. What's going on here?

[Stefan Kottwitz]

You just forgot a closing brace } at the end of the macro definition.

Stefan

[Johannes_B]

Underlining some space works nicely, but seems a bit strange. How about using the simple and built-in rule?

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\documentclass{article}
\newlength{\answerlinethickness}
\setlength{\answerlinethickness}{.4pt}
\newlength{\defaultlinelength}
\setlength{\defaultlinelength}{1.5em}
\newcommand{\answerline}[1][\defaultlinelength]{\rule{#1}{\answerlinethickness}}
\begin{document}
And the asnwer is \answerline[2cm].

\begin{displaymath}
\begin{array}{r@{= \answerline}}
	3+4 \\
	7+1 \\ 
	47 + 7 \\
\end{array}
\end{displaymath}
\setlength{\answerlinethickness}{1pt}
And the asnwer is \answerline[2cm].
\end{document}

Here we use an optional argument to set the length of the line. The default value was set to 1.5em; 150% the width of the letter M.

[LaTexLearner]

You just forgot a closing brace } at the end of the macro definition.

Stefan

Gah, ok. Thanks. The macro is working now.

Is that usually what that error message means when it says the definition is not good?

[LaTexLearner]

Underlining some space works nicely, but seems a bit strange. How about using the simple and built-in rule?
...

I'm trying to make sense of the \rule command. According to the LaTeX wiki the \rule command has 3 arguments. I get width and height. What is that optional one, depth?

[LaTexLearner]

I'm going to put my understanding of the code inside the code. Let's see if I actually understand it.

Underlining some space works nicely, but seems a bit strange. How about using the simple and built-in rule?

Code: Select all

\documentclass{article}

\newlength{\answerlinethickness}
\setlength{\answerlinethickness}{.4pt}
\newlength{\defaultlinelength}
\setlength{\defaultlinelength}{1.5em}

%These lines define the "ingredients" of the answer space macro below... but why did the first two have to \newLENGTH and \setLENGTH if they're actually setting THICKNESS?
%Those "ingredients" are how thick the answer line should be and how long they should be if not otherwise specified.
%This is also where I could adjust the default length and thickness of all answer lines in the whole document.



\newcommand{\answerline}[1][\defaultlinelength]{\rule{#1}{\answerlinethickness}}

%This is the actual answer line macro.
%These macros make it so that "\answerline" in the code will by default create a 1.5em line, but leaves the option open for \answerline[8cm] to create an 8cm line.
%There are two optional arguments here in the macro. 
%The first, [1], says how many optional arguments there can be in the code in the body.
%The 2nd, [\defaultlinelength], says that if the code in the body does not specify how long the answer line is, it should be whatever we set it to in the "ingredient" list above.


\begin{document}

And the answer is \answerline[2cm].

\begin{displaymath}
\begin{array}{r@{= \answerline}}
	3+4 \\
	7+1 \\ 
	47 + 7 \\
\end{array}
\end{displaymath}
\setlength{\answerlinethickness}{1pt}
And the asnwer is \answerline[2cm].
\end{document}

Is there any way I can make my comments in the code word wrap to make sideways scrolling unnecessary?

[LaTexLearner]

... Here we use an optional argument to set the length of the line. The default value was set to 1.5em; 150% the width of the letter M.

Does it have to be 1.5em? Could it also be 1.5ep or 1.53j? And would 1.5em change if the font changed the width of m? If so, wouldn't it be easier to set the default length, to, say, 0.6cm?

[Stefan Kottwitz]

Does it have to be 1.5em? Could it also be 1.5ep or 1.53j?

No. Designers usually consider the basic height of a lower case character and the width of a (wide) lowercase character as a property for referencing. x was chosen as height sample, m as width sample. Other characters usually scale proportionally. That means, if n would be 80% of the width of an m, the relation stays the same if you would resize the font. The width of m is the reference.

And would 1.5em change if the font changed the width of m? If so, wouldn't it be easier to set the default length, to, say, 0.6cm?

Yes, em changes with the m glyph. But, easier or not, there's a purpose: if your drawing should scale with the font, choose em and ex, if it should stay the same even if you would change to a larger font, choose cm, pt, or any other absolute value. The relative values em and ex are very useful, since you don't need to adjust a lot of absolute values in case of a font size change.

Stefan

[LaTexLearner]

I see... that makes a lot of sense.

So this means 1.5em will change not only if I switch the font *size* but if I switch from, say, Arial to Times New Roman (if the "m" changes width in those).

[Johannes_B]

I'm trying to make sense of the \rule command. According to the LaTeX wiki the \rule command has 3 arguments. I get width and height. What is that optional one, depth?

As often, the LaTeX Wiki Book is strange, but who has the time to make changes?

The optional argument of the rule command is a raise, you can move the rule up or down using a length there. Best place to look up stuff like that is the unofficial LaTeX2e manual (texdoc latex2e)