I have a bunch of markdown files, where I want to search for Ruby's double colon :: outside of some code formatting (e.g. where I forgot to apply proper markdown). For example

`foo::bar`

hello `foo::bar` test
`  example::with::whitespace  `

```
Proper::Formatted
```

```
  Module::WithIndendation
```

```
Some::Nested::Modules
```

```ruby
CodeBlock::WithSyntax
```

# Some::Class

## Another::Class Heading
some text

The regex only should match Some::Class and Another::Class, because they miss the surrounding backticks, and are also not within a multiline code fence block.

I have this regex, but it also matches the multi line block

[\s] [^`] (::)[^`] [\s]?

Any idea, how to exclude this?

EDIT: It would be great, if the regex would work in Ruby, JS and on the command line for grep.

CodePudding user response：

For the original input, you may use this regex in ruby to match :: string

1. not preceded by a ` and

2. not preceded by ` followed a white-space:

Regex:

(?<!`\s)(?<!`)\b\w ::\w 

RegEx Demo 1

RegEx Breakup:

• (?<!\s): Negative lookbehind to assert that <code> and whitespace is not at preceding position
• (?<!): Negative lookbehind to assert that <code> is not at preceding position
• \b: Match word boundary
• \w : Match 1 word characters
• ::: Match a ::
• \w : Match 1 word characters

You can use this regex in Javascript:

(?<!`\w*\s*|::)\b\w (?:::\w ) 

RegEx Demo 2

For gnu-grep, consider this command:

grep -ZzoP '`\w*\s*\b\w ::\w (*SKIP)(*F)|\b\w ::\w ' file |
xargs -0 printf '%s\n'

Some::Class
Another::Class

RegEx Demo 3