# Use catcode for alternative way of writing fractions

Writing fractions using different syntax would sometimes be useful, instead of using \frac{ab}{cd}, I would prefer to write something like \frac{ab⌂cd} where the Unicode ⌂ is the }{.

n.b., I don't want to mess with the \frac definition, but rather something like \newcommand{\myfrac}[2]{#1⌂#2}

Approach-My understanding of TeX is limited, but I think I can use catcode to do this, My understanding is that:

• \catcode @=2 is equivalent to }
• \catcode @=1 is equivalent to {

However just writing

\catcode\⌂=\active
\def ⌂{ \catcode @=2 \catcode @=1 }

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You can do simpler: \def\myfrac#1⌂#2{\frac{#1}{#2}}. –  Eddy_Em Jan 23 '13 at 7:05
@Eddy_Em: But then you would still need to introduce grouping braces like \myfrac25⌂{36} because \myfrac25⌂36 would be displayed as (25/3)6. –  canaaerus Jan 23 '13 at 7:12
I add an answer, but be careful in choosing of last symbol (apostrophe in this case): it shouldn't be in argument of \myfrac. –  Eddy_Em Jan 23 '13 at 7:16
Maybe something like: \catcode⌂=13 \let⌂\over ${1⌂2}$ \bye? –  morbusg Jan 23 '13 at 8:11

I have koi8-r locale & don't work with unicode, so instead of ⌂ I'll use |:

First define a command:

\makeatletter
\def\myfrac@#1|#2'{\frac{#1}{#2}}
\def\myfrac#1{\myfrac@#1'}
\makeatother


Then use it:

example: $\myfrac{10|20}$

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Thanks, this works perfectly! However, I am wondering if there is a way to do this along the lines I specified..it would be nice to know my way around catcode –  georg Jan 23 '13 at 7:19
@georgraba Catcodes have nothing to do with this: see tex.stackexchange.com/questions/16410/what-are-category-codes for a starter on them. –  Joseph Wright Jan 23 '13 at 7:21