Hi,

I was trying to create a composed grammar for Gyb (https://github.com/apple/swift/blob/master/utils/gyb.py). Gyb is mostly Swift code, with some snippets of Python embedded. For embedding the Python code you surround the code with `%{ }%` or start the lines with `%`.

For parsing Swift or Python code I’m using the official bundles (https://github.com/textmate/swift.tmbundle and https://github.com/textmate/python.tmbundle). For the injection I based my grammar on HTML (Rails) (https://github.com/textmate/ruby-on-rails-tmbundle/blob/master/Syntaxes/HTML...) which is mostly the same idea.

The grammar almost works. The embedded blocks are marked and the syntax highlight works, but I need to include a space before the percent signs for it to work, which is not ideal. It looks like the percent sign are interpreted as keyword.operator.remainder.swift (https://github.com/textmate/swift.tmbundle/blob/master/Syntaxes/Swift.tmLang...) before being able to be part of the injected grammar.

I found some references that “left scope match” (L:) might be able to help, but I cannot find a way to get it working.

A simple version of my grammar looks like this:

``` { injections = { 'source.swift.gyb - (meta.embedded.block.gyb)' = { patterns = ( { begin = '(^|\s*)(?=%{(?![^}]*}%))'; end = '(?!\G)(\s*$\n)?'; beginCaptures = { 0 = { name = 'punctuation.whitespace.embedded.leading.gyb'; }; }; endCaptures = { 0 = { name = 'punctuation.whitespace.embedded.trailing.gyb'; }; }; patterns = ( { include = '#tags'; } ); }, { include = '#tags'; }, ); }; }; patterns = ( { include = 'source.swift'; } ); repository = { tags = { patterns = ( { name = 'meta.embedded.block.gyb'; begin = '%{'; end = '(})%'; beginCaptures = { 0 = { name = 'punctuation.section.embedded.begin.gyb'; }; }; endCaptures = { 0 = { name = 'punctuation.section.embedded.end.gyb'; }; 1 = { name = 'source.python'; }; }; contentName = 'source.python'; patterns = ( { include = 'source.python'; } ); }, }, }, } ```

A text like this will work:

``` class MyClass { %{ a = 1 }% } ```

If I remove the space before the first percent sign, the grammar will not create the embedded block at all.

I tried using several scope selectors with `L:` to see if they work: - `L:(source.swift.gyb - (meta.embedded.block.gyb))` - `source.swift.gyb - (meta.embedded.block.gyb), L:source.swift.gyb` - `source.swift.gyb - (meta.embedded.block.gyb), L:source.swift` - `source.swift.gyb - (meta.embedded.block.gyb), L:source.swift keyword.operator.remainder.swift` - `source.swift.gyb - (meta.embedded.block.gyb), L:keyword.operator.remainder.swift`

None of them seem to work.

Does someone has any tips about what should I try next?

Thanks!