This question has been posted several times but...
I'm looking for a consistent implementation of the evaluation symbol:
- Evaluation bar as delimeter:
<...>|
- Auto-size to its enclosing expression:
\left<...>\right
What I'm not looking for is:
- Evaluation bar as relation:
<...>\mid
- Manual-size to its enclosing expression:
<...>bigg|
- A whole macro!
Now, the problem is that \rvert
does not auto-size, whereas \left.
inserts extra spacing.
Perfect would be something of the form \left_
telling latex to enclose the expression here while inserting no delimiter from the left at all, no matter wether visible or invisible.
Do you have an idea how to implement the evaluation bar?
(Not just circumventing the problem!)
As an example consider:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
y(a)&=\frac12 x^2|_a\\
y(a)&=\frac12 x^2\rvert_a\\
y(a)&=\left.\frac12 x^2\right|_a
\end{align}
\end{document}
\documentclass{...}
and ending with\end{document}
.