Structured text language support

[Serhioromano]

As discussed in #1923 here is PR

[Serhioromano]

I've solved conflicts. But that does not look intuitive. I thought the build process can run npx gulp and generate those files.

[RunDevelopment]

Thank you @Serhioromano for this PR!

I left you a few comments with things to improve.
And please fix the indentation of your language definition and test files. We only use tabs.

Regarding the merge conflict:
Seems like you fork wasn't up to date. To fix this:

1. Update your fork and merge these changes into this branch
2. Revert all changes you made to prism-show-language.js
3. Run npx gulp

[Serhioromano]

I do not know why checks fail. It does work for local when I run npm run test****

[RunDevelopment]

What is npm run test****?
If you run npm test you should see this:

  2 failing
  1) Patterns of 'iecst'
       - should have a capturing group if lookbehind is set to true:
     Error: Token <languages>.iecst.type.pattern: The pattern is set to 'lookbehind: true' but does not have a capturing group.
      at forEachPattern (tests/pattern-tests.js:124:10)
      at Context.<anonymous> (tests/pattern-tests.js:184:3)
  2) Patterns of 'iecst'
       - should not have unused capturing groups:
     Error: Token <languages>.iecst["class-name"]: Unused capturing group (PROGRAM|CONFIGURATION|INTERFACE|FUNCTION_BLOCK|FUNCTION|ACTION|TRANSITION|TYPE|STRUCT|(?:INITIAL_)?STEP|NAMESPACE|LIBRARY|CHANNEL|FOLDER|RESOURCE|VAR_(?:GLOBAL|INPUT|PUTPUT|IN_OUT|ACCESS|TEMP|EXTERNAL|CONFIG)|VAR|METHOD|PROPERTY). All capturing groups have to be either referenced or used as a Prism lookbehind group.
      at forEachPattern (tests/pattern-tests.js:124:10)
      at Context.<anonymous> (tests/pattern-tests.js:261:3)

[Serhioromano]

This is how I run tests

[Serhioromano]

By reading your messages I applied some changes. I didn't know where to see those messages.

[RunDevelopment]

Please revert these changes. While the file might need a cleanup, it shouldn't be part of this PR.

The only change to this file should be this:

 		"ichigojam": "IchigoJam",
+		"iecst": "Structured Text (IEC 61131-3)",
 		"inform7": "Inform 7",

[Serhioromano]

How? when I run npx gulp it rebuild this file and make them all one line.

[Serhioromano]

And yet, I am not sure how to revert a single file change. Out of my knowledge. I'll try to google it.

[RunDevelopment]

The easiest way would probably to copy-paste the content of the current prism-show-language.js in master and run npx gulp.

There's probably also some fancy git-way of doing it, but I'm not a git expert...

[RunDevelopment]

This is how I run tests

This only checks your language against your .test files. We also have a few other tests which scan all patterns for potential errors (like the unnecessary lookbehind: true).
npm test runs all tests for all languages and basically verifies that Prism is fully functional.

By reading your messages I applied some changes. I didn't know where to see those messages.

What I showed you was the build log of Travis CI. To see this, click on the red X behind a commit on GitHub, click Details, choose any red (failed) build job, scroll waaaaay down.

[Serhioromano]

I'll create a new PR. This copy of prism was forked years ago and propbably rebase did not work well.

[RunDevelopment]

New PR: #2311