probablykasper / cpc

Text calculator with support for units and conversion

Hi, I'm a developer from Norway

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cpc's Issues

Negative exponents are calculated incorrectly without parenthesis

As of 1.9.2, cpc incorrectly calculates the sign of negative exponents without parenthesis

Expression	Result	Expected
-3^2	9	-9
(-3)^2	9	9

Synonyms for operators

Is it possible to support queries like this?

❯ ./cpc '500 divided by 4'
Lexing error: Invalid string: divided

How to calculate percents correctly?

qalc 90+10%=99, but cpc 90+10%=90.1

Support non-US spelling of words

These examples should work, but don't:

❯ ./cpc '24 kilometres per hour in metres per second'
Lexing error: Invalid string: kilometres

❯ ./cpc '24 kilometers per hour in metres per second'
Lexing error: Invalid string: metres

I'm guessing there are probably others that need fixing up; I didn't perform a comprehensive test of all supported units.

Dividing by a unit over time

I haven't been able to find a way to make this kind of query work:

❯ ./cpc '500 megabytes / 3 megabytes per second'
Parsing error: Expected end of input, found LexerKeyword(Per) at 5

❯ ./cpc '500 megabytes / 3 megabytes/second'
Eval error: Unit has no child[0]

Thanks for creating this project by the way, it looks amazing :) Queries like this are one thing I still tend to use Google for, so I see it as a way to continue de-googling my life.

Inputs need to be quoted

It doesn't appear to be stated anywhere in the readme, but as far as I can tell the full input query needs to be quoted and passed as a single argument on the shell. This was quite frustrating until I worked it out.

I think the readme should be updated to state this. I also think the examples section of the readme should be updated to include the expected results. This will assist users in testing the program.

Output formatting improvements

Currently the output doesn't produce nice human-readable descriptions, and doesn't differentiate between singular and plural values.

❯ target/release/cpc '123 kph'
123 KilometersPerHour

❯ target/release/cpc '1 kph'
1 KilometersPerHour

It would be good if the output of the above was 123 kilometres per hour and 1 kilometre per hour.

Quarter unit treated as month

I believe there's a typo in lexer.rs where (a) quarter is misspelled as quater (and quaters) and (b) the unit assigned is Unit::Month instead of Unit::Quarter.

AUR package

I've published a package for cpc on the AUR:

https://aur.archlinux.org/packages/cpc-calc/

I figured I'd let you know in case you want to add a note to the readme.

Trig functions result in floating point error

Description: using "pi" with trig functions results in close but wrong floating point results

Steps to reproduce: cpc 'sin(pi)' or cpc 'sin(pi/2)'

Expected result: 0 and 1 respectively

Actual result: 5.012535993076719585277299108368256E-35 and 1.000000000000000000000000000000001

Add CI to run the tests

It would be good to set up something like Github actions to run the tests, so that they're automatically validated when someone submits a PR.

Improvement: Allow to not use quotes when invoking from the command line

I find this package really helpful to operate from the CLI, however it would be really handy to just type cpc 2 + 2 instead of cpc '2 + 2'.

I created a bash script to do cpc "$*" this work just fine, but not for multiplication and I don't necessarily want to write a wrapper around this issue, especially if it could be provided out of the box.

Merely food for thought.

cargo-audit finds rustc-serialize vulnerability

Hi @probablykasper , running cargo audit returns:

Crate: rustc-serialize
Version: 0.3.24
Title: Stack overflow in rustc_serialize when parsing deeply nested JSON
Date: 2022-01-01
ID: RUSTSEC-2022-0004
URL: https://rustsec.org/advisories/RUSTSEC-2022-0004
Solution: No fixed upgrade is available!
Dependency tree:
rustc-serialize 0.3.24
└── decimal 2.1.0
└── cpc 1.8.0

error: 1 vulnerability found!

Any chance an alternative library for decimal can be used?

Handle scientific notations correctly

Currently CPC couldn't handle scientific notations such as "2e10" and "1e-3". It will calculate it as 2 * e * 10, and 1 * e * (-3). Can we fix that?

There should be a way for the program to print help text

Right now trying to run cpc --help just produces an error. It would be nice if it could print a summary of what the program is capable of.