# Generic Go lexer

A very simple state-based lexer.

```go
import "src.userspace.com.au/lexer"

// Define the tokens for the lexer.
const (
	_ lexer.TokenType = iota
	tBREStart
	tBREEnd
	tRangeStart
	tRangeDash
	tRangeEnd
	tCharacter
	tClass
	tNot
)

// Define states returning a StateFunc.
func startState(l *lexer.Lexer) lexer.StateFunc {
	l.SkipWhitespace()
	r := l.Next()
	if r != '[' {
		return l.Error("expecting [")
	}
	l.Emit(tBREStart)
	return beFirstState
}
```

For a complete (but simple) example see the code in a [bracket expression
generator](https://src.userspace.com.au/bechars/tree/lexer.go).


src.userspace.com.au/lexer

lexer

(Experimental) An ambiguous license classifier was found.

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Ambiguous License Classifier

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

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

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Bad semver

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Bad dependency semver

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Bidirectional unicode control characters

This package has multiple bin scripts with the same name. This can cause non-deterministic behavior when installing or could be a sign of a supply chain attack.

What is bin script confusion?

Bin script confusion

This Chrome extension includes content scripts that execute JavaScript on specified websites.

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Chrome: Content Script

This Chrome extension requests host permissions to access specific websites or domains.

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Chrome: Host Permission

This Chrome extension requests permissions to access browser APIs, user data, or system features.

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Chrome: Permission

This Chrome extension requests wildcard host permissions that grant broad access to websites.

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Chrome: 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.

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Compromised SSH key

(Experimental) Copyleft license information was found.

What do I need to know about license files?

Copyleft License

Contains a Critical Common Vulnerability and Exposure (CVE).

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Title

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

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High CVE

Uses debug, reflection and dynamic code execution features.

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Debug access

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Deprecated

(Experimental) Contains a known deprecated SPDX license exception.

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Package name is similar to other popular packages and may not be the package you want.

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Possible typosquat attack

Dynamic require can indicate the package is performing dangerous or unsafe dynamic code execution.

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Dynamic require

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Empty package

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File dependency

Accesses the file system, and could potentially read sensitive data.

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Filesystem access

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Wildcard dependency

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Alert title

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An input argument to this GitHub Action is being exported as an environment variable. If a user of this action passes untrusted input, it could be used in an insecure manner by subsequent workflow steps.

What are GitHub Actions taint flows?

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An input argument to this GitHub Action is being passed back as an output. If a user of this action passes untrusted input, it could be used in an insecure manner by consuming workflows.

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An input argument to this GitHub Action flows into a dangerous sink (such as shell command execution). This could allow a malicious user to inject commands or exploit the action.

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A GitHub context variable (such as issue title, PR description, or comment body) is being exported as an environment variable. These context values are user-controlled and could be exploited by subsequent workflow steps.

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A GitHub context variable (such as issue title, PR description, or comment body) flows into a dangerous sink (such as shell command execution). This is a critical security issue that could allow command injection or code execution attacks.

GitHub Actions: GitHub context variable flows to dangerous sink

An environment variable flows into a dangerous sink (such as shell command execution). If this environment variable comes from an untrusted source, it could be exploited to inject commands.

GitHub Actions: Environment variable flows to dangerous sink

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AI has identified this package as a potential typosquat of a more popular package. This suggests that the package may be intentionally mimicking another package's name, description, or other metadata.

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AI-detected possible typosquat

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AI-detected potential malware

AI has determined that this package may contain potential security issues or vulnerabilities.

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AI-detected potential security risk

Contains native code (e.g., compiled binaries or shared libraries). Including native code can obscure malicious behavior.

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Native code

Contains high entropy strings. This could be a sign of encrypted data, leaked secrets or obfuscated code.

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High entropy strings

Contains unicode homoglyphs which can be used in supply chain confusion attacks.

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Unicode homoglyphs

Contains a dependency which resolves to a remote HTTP URL which could be used to inject untrusted code and reduce overall package reliability.

What are http dependencies?

HTTP dependency

Install scripts are run when the package is installed or built. Malicious packages often use scripts that run automatically to execute payloads or fetch additional code.

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Install scripts

Package has an invalid manifest file and can cause installation problems if you try to use it.

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Invalid manifest file

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Invisible chars

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Manifest confusion

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This package contains minified code. This may be harmless in some cases where minified code is included in packaged libraries, however packages on npm should not minify code.

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Minified code

(Experimental) A package's licensing information has fine-grained problems.

Misc. License Issues

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Modified license exception

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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.

src.userspace.com.au/lexer

Generic Go lexer

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