Add support for HCL

[outsideris]

Supporting HCL(HashiCorp Configuration Language).
Close #1252

[RunDevelopment]

Thank you for creating this language definition!

There are, however, a few things we have to fix before we can merge this. Apart from the comments, I left you, these things have to be addressed:

1. Please don't use capturing groups when you don't need to. This is confusing because I expect the captured text to be used in some way. So please use non-capturing groups.
2. There are a few cases where you have lists of tokens with only one pattern ('abc': [ { /* stuff */ } ]). Just assign the pattern to the token ('abc': { /* stuff */ }).
   Same goes for pattern objects of the form: { pattern: /regex/ }. You can always just inline /regex/.
3. Multiline strings are not supported.
4. Please add a punctuation token for the brackets of objects and arrays.

After that is done, I will continue to review your PR.

Also, I'm not very familiar with HCL so please tell me if I made a mistake somewhere.

[outsideris]

Sorry for late, I will fix them until next weekend.

[robmorgan]

@outsideris any luck? need a hand?

[outsideris]

I started to work on it.
Sorry, I really was busy for company things.

[outsideris]

I'm updating code as your great feedback. Thank you!!
I will push new commits soon after I'm done. Sorry for late response.

[robmorgan]

@outsideris no need to apologise for open source work mate ;)

[outsideris]

I modified them as your feedback.

[RunDevelopment]

@outsideris I'm sorry, I missed your last commit! I will review the changes ASAP.

[maartenvanderhoef]

@outsideris Will this also parse hcl2 ? If not, would it be an idea to name this hcl1 ?

[outsideris]

@maartenvanderhoef It is not parse hcl2 and hcl2 is still experimental.
For me, name "hcl" is fine because HashiCorp also call them as "HCL" and "HCL2". How do you think?

[outsideris]

I rebased onto latest master.

[maartenvanderhoef]

hi @outsideris, you're right, let's stick Hashicorp's own naming.

[RunDevelopment]

Sorry for the delay!

I have a few problems beside my comments:

1. Indentation.
2. The use of capturing groups when the captured content is not used.
   You use capturing groups a lot and they are necessary for lookbehinds and backreferences but all groups which are not used in that way should be non-capturing.
   This is to make the patterns easier to understand because if there is a capturing group, you'll expect the captured text to be used.
3. Unnecessary surrounding array/objects.
   In a few places, there is an array wrapped around a single object (e.g. 'type': [ { /* pattern and so on */ } ] in which case you can replace the array with its content.
   In other places, there are objects which only contain the pattern property. Those can be replaced with the pattern itself.
   Again to make it easier to read and understand.
4. Instead of [\w-]+|"[\w-]+" you should use [\w-]+|"(?:[^\n\r\\"]|\\.)*" to captur things like "abc\"def": 8.

We will talk about interpolation, greedy strings and the keyword patterns once this is done.
Again, I'm really sorry for the delay.

[outsideris]

I fixed as your feedback. Sorry for bordering you because I'm not regexp expert.

[RunDevelopment]

A few more things and then we can talk about interpolation.

Also, please replace all arrays which only contain one item with said item. A good example of this is interpolation.

(And don't worry. That doesn't borther me at all. Nobody is a regex master from the get go.)

[outsideris]

Also, please replace all arrays which only contain one item with said item.

I believe I didn't understand what you mean exactly. I can't find more arrays which only contain one item.

[RunDevelopment]

Maybe another example: hcl.keyword.inside.type is currently defined as follows:

'type': [ // start of array
	{	// one item
		pattern: /(resource|data|\s+)(?:[\w-]+|"[\w-]+")/i,
		lookbehind: true,
		alias: 'variable'
	}
] // end of array

But this can be replaced with a simpler expression:

'type': {
	pattern: /(resource|data|\s+)(?:[\w-]+|"[\w-]+")/i,
	lookbehind: true,
	alias: 'variable'
}

Other examples like this can be found on line 7, 19, 32, 36, and 48.

[outsideris]

fixed.

[RunDevelopment]

@outsideris
Good!
The things left to do now are:

1. Interpolation as discussed here.
2. Here-doc strings.

[outsideris]

@RunDevelopment
I moved interpolation into string as your advice. Thanks. -> 8022bed
I supported heredoc. -> c05d498

[RunDevelopment]

Good work!

I left you a few comments and after that is done, I think we are ready to merge this.

[outsideris]

I changed them as your feedback.

[RunDevelopment]

Looks good!

Two small things:

1. Please make comment the first pattern and heredoc greedy. This will solve the problem of false comments inside heredoc strings.
2. Please replace all occurrences of "?[\w-]+"? and [\w-]+|"[\w-]+" with (?:[\w-]+|"(?:\\[\s\S]|[^\\"])*"). All of these occurrences are in keyword.

[outsideris]

Fixed! :)

[outsideris]

Done.

[outsideris]

@RunDevelopment Fixed. Sorry for I missed it.

[outsideris]

@RunDevelopment You are awesome. I couldn't make this PR without you. Thank you.

[robmorgan]

Good job! 👍