evaluate terms in zsh without a command

I am using zsh with the [prezto](https://github.com/sorin-ionescu/prezto) configuration framework. I want to be able to type in terms like 1 + 2 * (3 / 4) and get "2.5" out of it. Those terms could be recognized because they only consist of certain characters: 0123456789 +-*/(). For everything more complicated I am fine with opening a dedicated program (like a python shell). ## solutions that are not good enough 1. **Use a program**: I don't want to type python -c before my term or pipe it into bc. That's too much typing and I hope it can be done better. 2. **Use a function or an alias**: There are some [solutions](https://github.com/arzzen/calc.plugin.zsh) out there that allow to do these calculation when prefing it with a c or = or calc, like in = 1 + 2 * (3 / 4). That is nice but basically the same thing as point 1. 3. **Use another shell**: I know about [xonsh](https://xon.sh/) and I am sure there are other shells that can do that. But I like zsh and I don't want to change shells. ## what might work 4. **zsh plugin**: I could imagine a zsh-plugin that finds if a command matches a certain regex and then pipes it into python/bc/whatever. Somewhat similar to what the automatic cd thing does when you enter just the name of a directory. I don't know if this is possible though. I would love to hear some hints so I could write that. 5. **Intercept command not found**: Similar to 4. perhaps it is possible to intercept the behaviour of zsh when a command is not found. But again, I don't know how I would do that. 6. **alias all the numbers**: I guess you could write an alias for all the numbers so that they are commands that take the rest of the math-string as arguments. That might work, but seems pretty hacky. Also 'all the numbers' is quite a lot aliases, even when autogenerating the code for it. I would like to hear ideas on how to tackle this problem. I am not afraid of writing code, but I would prefere a clean solution over a hacky one.