# How to define the following symbol to stock one element in one list?

I'm looking for one symbol to indicate that a value is stocked in one list. On way would be to use something like myList.append(myValue) but it os not very quick to see and to write.

Indeed, I would like to define the following symbols that is a left arrow followed by one square. This symbol will be used in math formulas.

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Have you looked through the comprehensive symbols guide for an appropriate symbol? –  mafp Jan 19 '13 at 10:15
No, indeed I hope that someone has already find this. If I have one idea, I would have ask how to obtain that symbol. –  projetmbc Jan 19 '13 at 10:20
OK. While I do write algorithms with lists, I never came across a special symbolic way for expressing appending. –  mafp Jan 19 '13 at 10:28
You just write it like I'm doing but maybe some symbolic notations could help for faster reading. This is why I'm looking for something more formal. –  projetmbc Jan 19 '13 at 10:30

\boxleft from pxfonts package will do something similar to what you want:

The package also has these other symbols:

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You can add a square to an arrow, if your fonts don't have the symbol.

\documentclass{article}
\usepackage{amssymb}
\newcommand{\stock}{\gets\mathrel{\mkern-2.4mu\mathop\square}}

\begin{document}
$L\stock a$
\end{document}


With \mathop\square we vertically shift the square so that it's aligned with the arrow at mid height. With \mathrel we ensure no space will be added other than the explicit back up we're doing. The resulting symbol is considered as a relation, as far as spacing is concerned.

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The whole definition should be included in a extra group, or perhaps a \mathrel, otherwise the user gets a surprise with $$L^\stock$$. –  Andrew Swann Feb 6 '13 at 15:19
A couple of braces wouldn't help, as it would change the nature of the symbol; a \mathrel wouldn't help either. It wouldn't be the only symbol with this problem and that's one of the reasons why I always teach x^{...} even if the exponent consists of one symbol. –  egreg Feb 6 '13 at 15:47
You are right - if want doesn't want the \mathord class then one is stuck with have to put braces on the superscript. I now see that this property shared by standard commands such as \cong and \notin. I hadn't noticed it before. –  Andrew Swann Feb 6 '13 at 15:56