How to define begin and end patterns which span multiple lines?

Hi, I’m trying to expand the support for my plugin, graphql-for-vscode, to support gherkin feature files, but I’m stuck while defining the grammer. The begin regexp seems to not do any matching when I specify a newline (\n):

Specifically:

With this syntax definition:

{
  "fileTypes": ["feature"],
  "scopeName": "text.gherkin.feature.graphql",
  "injectionSelector": "L:text -comment",
  "patterns": [
    {
      "begin": "graphql request\\s+\"\"\"",
      "end": "\"\"\"",
      "patterns": [
        {
          "name": "featureGQL",
          "include": "source.graphql"
        }
      ]
    }
  ]
}

I don’t get any matches:

but modifying the source text to bring the beginning """ to the same line as graphql request does the trick:

I tried modifying the begin regexp to be: "begin": "graphql request\\n\\s+\"\"\"", but it didn’t help - in fact, it stopped highlighting anything within quotes.

I’ve spent some time browsing other syntaxes in vscode and textmate, but could only find \n to be used in match regexp sections, but none yet in begin or end sections.

[ghost]

@kumarharsh For situations like this you have to make use of oniguruma lookarounds.

Here is a modification of your original example using a lookbehind:

{
  "injectionSelector": "L:text -comment",
  "patterns": [
    {
      "begin": "graphql request\\s*$",  // STAGE_1
      "end": "(?<=\"\"\")", // end if the last token consumed was the closing """
      "patterns": [
        {
          "begin": "^\\s*(\"\"\")$",  // STAGE_2
          "end": "^\\s*(\"\"\")",
          "patterns": [
            { "include": "source.graphql" }
          ]
        }
      ]
    },
  ]
  ...
}

Alternatively you can use a lookahead (although I find this is usually a worse choice):

{
  "injectionSelector": "L:text -comment",
  "patterns": [
    {
      "begin": "graphql request\\s*$",  // STAGE_1
      "end": "(\"\"\")$",
      "patterns": [
        {
          "begin": "^\\s*(\"\"\")$",  // STAGE_2
          "end": "^\\s*(?=\"\"\")",
          "patterns": [
            { "include": "source.graphql" }
          ]
        }
      ]
    },
  ]
  ...
}

One pattern you will want to use to match multi-line syntactic constructs accurately is as follows. This is what I was referring to earlier about chaining “begin”/“end” matches. You might want to adapt your example to this style depending on how many stages there will be after the first quoted block.

{
  "patterns": [
    {
      "begin": "A",
      "end": "B",
    },
    {
      "begin": "(?<=B)",
      "end": "C",
    },
    {
      "begin": "(?<=C)",
      "end": "D",
    },
    …
  ]
}

[kumarharsh]

The L: part means left injection, i.e., the grammar rules are injected to the left of the existing rules for the scope being highlighted. When doing syntax highlighting, the left-most rule has higher precedence than the rules to it’s right. So the L: ensures that this syntax highlighting will override the default ones.

Ref: https://github.com/textmate/markdown.tmbundle/issues/15#issuecomment-18321960