evaler
======

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https://github.com/bocajim/evaler

Project forked from https://github.com/soniah/evaler

Package evaler implements a simple floating point arithmetic expression evaluator.

Evaler uses Dijkstra's Shunting Yard algorithm [1] to convert an infix
expression to postfix/RPN format [2], then evaluates the RPN expression. The
implementation is adapted from a Java implementation at [3]. The results are
returned as a `math/big *big.Rat`.

This is release 2.0. The previous version that returned results as float64
is in the branch float64.

Usage
-----

```go
result, err := evaler.Eval("1+2")
```

Operators
---------

The operators supported are:

```+ - * / ** () < >```

< (less than) and > (greater than) will get lowest precedence, all
other precedence is as expected (BODMAS [4]).

< and > tests will evaluate to 0.0 for false and 1.0 for true, allowing
expressions like:

```
3 * (1 < 2) # returns 3.0
3 * (1 > 2) # returns 0.0
```

Minus implements both binary and unary operations (thanks @hiroxy).

Issues
------

The math/big library doesn't have an exponent function (**), and implenting one
for big.Rat numbers is non-trivial. As a work around, arguments are converted
to float64's, the calculation is done using the math.Pow() function, the
result is converted to a big.Rat and placed back on the stack.

Documentation
-------------

http://godoc.org/github.com/bocajim/evaler

There are also a number of utility functions (eg BigratToFloat(),
BigratToInt()) that may be useful when working with evaler.

Original Author
------
Sonia Hamilton
http://blog.snowfrog.net
sonia@snowfrog.net

License
-------
Modified BSD License (BSD-3)

Links
-----

[1] http://en.wikipedia.org/wiki/Shunting-yard_algorithm

[2] http://en.wikipedia.org/wiki/Reverse_Polish_notation

[3] http://willcode4beer.com/design.jsp?set=evalInfix

[4] http://www.mathsisfun.com/operation-order-bodmas.html



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github.com/bocajim/evaler

evaler

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What is an ambiguous license classifier?

Ambiguous License Classifier

Source files are encoded using a non-standard text encoding.

What is bad text encoding?

Bad text encoding

Package version is not a valid semantic version (semver).

What is bad semver?

Bad semver

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What is bad dependency semver?

Bad dependency semver

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What are bidirectional unicode control characters?

Bidirectional unicode control characters

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What is bin script confusion?

Bin script confusion

This Chrome extension includes a content script '{scriptFile}' that runs on websites matching '{matches}'.

What are Chrome extension content scripts?

Chrome Extension Content Script

This Chrome extension requests access to '{host}'.

What are Chrome extension host permissions?

Chrome Extension Host Permission

This Chrome extension uses the '{permission}' permission.

What are Chrome extension permissions?

Chrome Extension Permission

This Chrome extension requests broad access to websites with the pattern '{host}'.

What are Chrome extension wildcard host permissions?

Chrome Extension Wildcard Host Permission

Semantic versions published out of chronological order.

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Chronological version anomaly

Project maintainer's SSH key has been compromised.

What is a compromised SSH key?

Compromised SSH key

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Copyleft License

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Title

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High CVE

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What is debug access?

Debug access

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Deprecated

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Deprecated license

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Possible typosquat attack

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Dynamic require

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Empty package

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Name

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File dependency

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Filesystem access

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Wildcard dependency

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What are git dependencies?

Git dependency

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GitHub dependency

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What is an AI-detected potential code anomaly?

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AI-detected potential malware

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AI-detected potential security risk

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Why is native code a concern?

Native code

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High entropy strings

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Unicode homoglyphs

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What are http dependencies?

HTTP dependency

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Install scripts

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What is an invalid manifest file?

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What are invisible characters?

Invisible chars

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License Policy Violation

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What's wrong with long strings?

Long strings

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Major refactor

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Known malware

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What is manifest confusion?

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Contains a medium severity Common Vulnerability and Exposure (CVE).

What is a medium CVE?

Medium CVE

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What is a modified license?

Modified license

What is network access?

Network access

A new npm collaborator published a version of the package for the first time. New collaborators are usually benign additions to a project, but do indicate a change to the security surface area of a package.

What is new author?

New author

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Why is contributor and author data important?

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Why are missing repositories important?

No repository

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github.com/bocajim/evaler

evaler

Usage

Operators

Issues

Documentation

Original Author

License

Links

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