%YAML 1.2
---
name: Ruby
# TODO: unresolved issues
#
# text:
# "p << end
# print me!
# end"
# symptoms:
# not recognized as a heredoc
# solution:
# there is no way to distinguish perfectly between the << operator and the start
# of a heredoc. Currently, we require assignment to recognize a heredoc. More
# refinement is possible.
# • Heredocs with indented terminators (<<-) are always distinguishable, however.
# • Nested heredocs are not really supportable at present
#
# text:
# print <<-'THERE'
# This is single quoted.
# The above used #{Time.now}
# THERE
# symtoms:
# From Programming Ruby p306; should be a non-interpolated heredoc.
#
# text:
# "a\332a"
# symptoms:
# '\332' is not recognized as slash3.. which should be octal 332.
# solution:
# plain regexp.. should be easy.
#
# text:
# val?(a):p(b)
# val?'a':'b'
# symptoms:
# ':p' is recognized as a symbol.. its 2 things ':' and 'p'.
# :'b' has same problem.
# solution:
# ternary operator rule, precedence stuff, symbol rule.
# but also consider 'a.b?(:c)' ??
file_extensions:
  - rb
  - Appfile
  - Appraisals
  - Berksfile
  - Brewfile
  - capfile
  - cgi
  - Cheffile
  - config.ru
  - Deliverfile
  - Fastfile
  - fcgi
  - Gemfile
  - gemspec
  - Guardfile
  - irbrc
  - jbuilder
  - podspec
  - prawn
  - rabl
  - rake
  - Rakefile
  - Rantfile
  - rbx
  - rjs
  - ruby.rail
  - Scanfile
  - simplecov
  - Snapfile
  - thor
  - Thorfile
  - Vagrantfile
first_line_match: ^#!\s*/.*\bj?ruby\b
scope: source.ruby
variables:
  identifier: '\b[[:alpha:]_][[:alnum:]_]*\b'
  method_punctuation: '(?:[?!]|=(?![>=]))?'
  method_name: '{{identifier}}{{method_punctuation}}'
  path_lookahead: '(::)?({{identifier}}(\.|::))*{{identifier}}'

contexts:
  main:
    - include: expressions

  expressions:
    - include: class
    - include: module
    - include: constants
    - include: invalid
    - include: blocks
    - include: keywords
    - include: well-known-methods
    - include: variables
    - include: method
    - include: strings
    - include: comments
    - include: data-section
    - include: heredocs
    - include: operators
    - include: identifiers-accessors

  comments:
    # multiline comments
    - match: ^=begin
      scope: punctuation.definition.comment.ruby
      push:
        - meta_scope: comment.block.documentation.ruby
        - match: ^=end
          scope: punctuation.definition.comment.ruby
          pop: true
    - match: '(#).*$\n?'
      scope: comment.line.number-sign.ruby
      captures:
        1: punctuation.definition.comment.ruby

  class:
    # Defining a class method
    - match: \b(class)\b(?=\s*<)
      scope: keyword.control.class.ruby
    - match: '\b(class)\b'
      scope: meta.class.ruby keyword.control.class.ruby
      push: class-declaration

  class-declaration:
    - meta_content_scope: meta.class.ruby
    - match: '(?={{path_lookahead}})'
      set: class-name
    # Escape if no valid match
    - match: (?=\S)
      pop: true

  class-name:
    - meta_content_scope: meta.class.ruby entity.name.class.ruby
    - include: name-parts
    - match: ''
      set: class-inheritance

  class-inheritance:
    - meta_content_scope: meta.class.ruby
    - match: '<'
      scope: punctuation.separator.inheritance.ruby
      set:
        - meta_content_scope: meta.class.ruby
        - match: '(?={{path_lookahead}})'
          set:
            - meta_content_scope: meta.class.ruby entity.other.inherited-class.ruby
            - include: name-parts
            - match: ''
              pop: true
        # Escape if no valid match
        - match: '(?=\S)'
          pop: true
    # Escape if no valid match
    - match: '(?=\S)'
      pop: true

  module:
    - match: \b(module)\b
      scope: meta.module.ruby keyword.control.module.ruby
      push: module-declaration

  module-declaration:
    - meta_content_scope: meta.module.ruby
    - match: '(?=(::)?({{identifier}}::)*{{identifier}})'
      set:
        - meta_content_scope: meta.module.ruby entity.name.module.ruby
        - include: name-parts
        - match: ''
          pop: true
    # Escape if no valid match
    - match: (?=\S)
      pop: true

  name-parts:
    - match: '::'
      scope: punctuation.accessor.ruby
    - match: '\.'
      scope: punctuation.accessor.ruby
    - match: '({{identifier}})(::|\.)'
      captures:
        1: support.other.namespace.ruby
        2: punctuation.accessor.ruby
    - match: '{{identifier}}'

  invalid:
    # else if is a common mistake carried over from other languages. it works if you put in a second end, but it’s never what you want.
    - match: \belse\s+if\b
      scope: invalid.deprecated.ruby

  constants:
    # constant definition, handles multiple definitions on a single line 'APPLE, ORANGE= 1, 2'
    - match: '\b([[:upper:]]\w*)(?=(\s*,\s*[[:upper:]]\w*)*\s*=(?![=\>]))'
      scope: meta.constant.ruby entity.name.constant.ruby
    # Ruby 1.9 symbols
    - match: '{{identifier}}[?!]?(:)(?!:)'
      scope: constant.other.symbol.ruby
      captures:
        1: punctuation.definition.constant.ruby
      push: try-regex
    - match: '\b(nil|true|false)\b(?![?!])'
      scope: constant.language.ruby
    - match: '\b(__(FILE|LINE|ENCODING)__|self)\b(?![?!])'
      scope: variable.language.ruby
    - match: '\b(0[xX]\h(_?\h)*|\d(_?\d)*(\.(?![^[:space:][:digit:]])(_?\d)*)?([eE][-+]?\d(_?\d)*)?|0[bB][01]+)\b'
      scope: constant.numeric.ruby
    - match: ":'"
      scope: punctuation.definition.constant.ruby
      push:
        - meta_scope: constant.other.symbol.single-quoted.ruby
        - match: "'"
          scope: punctuation.definition.constant.ruby
          pop: true
        - match: '\\[''\\]'
          scope: constant.character.escape.ruby
    - match: ':"'
      scope: punctuation.definition.constant.ruby
      push:
        - meta_scope: constant.other.symbol.double-quoted.ruby
        - match: '"'
          scope: punctuation.definition.constant.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
    # Unquoted symbols
    - match: |-
        (?x:
          (:)
          (
            {{identifier}}{{method_punctuation}}|
            ===?|
            >[>=]?|
            <[<=]?|
            <=>|
            [%&`/\|]|
            \*\*?|
            =?~|
            [-+]@?|
            \[\]=?|
            @@?{{identifier}}
          )
        )
      scope: constant.other.symbol.ruby
      captures:
        1: punctuation.definition.constant.ruby
    # matches questionmark-letters.
    #
    # examples (1st alternation = hex):
    # ?\x1     ?\x61
    #
    # examples (2nd alternation = octal):
    # ?\0      ?\07     ?\017
    #
    # examples (3rd alternation = escaped):
    # ?\n      ?\b
    #
    # examples (4th alternation = meta-ctrl):
    # ?\C-a    ?\M-a    ?\C-\M-\C-\M-a
    #
    # examples (4th alternation = normal):
    # ?a       ?A       ?0
    # ?*       ?"       ?(
    # ?.       ?#
    #
    # the negative lookbehind prevents against matching
    # p(42.tainted?)
    - match: '\?(\\(x\h{1,2}\b|0[0-7]{0,2}\b|[^x0MC]\b)|(\\[MC]-)+\w\b|[a-zA-Z0-9_]\b(?!\s*:)|[^a-zA-Z0-9_\s\\])'
      scope: constant.numeric.ruby

  blocks:
    - match: \b(do)\b\s*
      captures:
        1: keyword.control.start-block.ruby
      push: maybe-block-parameters
    - match: \{
      scope: punctuation.section.scope.ruby
      push: maybe-block-parameters

  maybe-block-parameters:
    - match: \|
      scope: meta.block.parameters.ruby punctuation.definition.parameters.begin.ruby
      set: block-parameters
    - match: (?=\S)
      pop: true

  block-parameters:
    - meta_content_scope: meta.block.parameters.ruby
    - match: \|
      scope: meta.block.parameters.ruby punctuation.definition.parameters.end.ruby
      set: try-regex
    - match: '{{identifier}}'
      scope: variable.parameter.ruby
    - match: ','
      scope: punctuation.separator.ruby
    - match: \*
      scope: keyword.operator.splat.ruby
    - match: '&'
      scope: keyword.operator.ruby
    - match: '(?==)'
      set:
        - meta_content_scope: meta.block.parameters.default-value.ruby
        - match: '='
          scope: keyword.operator.assignment.ruby
          set:
            - meta_content_scope: meta.block.parameters.default-value.ruby
            - match: '(?=[,\|])'
              set: block-parameters
            - include: nest-all
            - include: expressions

  keywords:
    - match: '\b(BEGIN|END)\b(?![?!])'
      scope: keyword.control.ruby
    - match: '\b(class|module)\b(?![?!])'
      scope: keyword.control.ruby
    - match: '\b(begin|end|ensure|rescue)\b(?![?!])'
      scope: keyword.control.ruby
    - match: '\b(case|else|ensure|for|in|then)\b(?![?!])'
      scope: keyword.control.ruby
    - match: '\b(elsif|if|unless|when|while|until)\b(?![?!])'
      scope: keyword.control.ruby
      push: after-keyword
    - match: \b(and|not|or)\b
      scope: keyword.operator.logical.ruby
      push: after-keyword
    - match: '!+|&&|\|\||\^'
      scope: keyword.operator.logical.ruby
      push: after-operator
    - match: '\b(alias|alias_method|break|next|redo|retry|return|super|undef|yield)\b(?![?!])|\bdefined\?|\bblock_given\?'
      scope: keyword.control.pseudo-method.ruby

  operators:
    - match: '=>'
      scope: punctuation.separator.key-value.ruby
      push: after-operator
    - match: '<<=|%=|&=|\*=|\*\*=|\+=|\-=|\^=|\|{1,2}=|<<'
      scope: keyword.operator.assignment.augmented.ruby
      push: after-operator
    - match: '<=>|<(?!<|=)|>(?!<|=|>)|<=|>=|===|==|=~|!=|!~'
      scope: keyword.operator.comparison.ruby
      push: after-operator
    - match: (%|&|\*\*|\*|\+|\-|/)
      scope: keyword.operator.arithmetic.ruby
      push: after-operator
    - match: '='
      scope: keyword.operator.assignment.ruby
      push: after-operator
    - match: \||~|>>
      scope: keyword.operator.other.ruby
      push: after-operator
    - match: \?
      scope: keyword.operator.conditional.ruby
      push:
        # Handle hash-key-lookalike of identifier: in ternary
        - match: '\s*{{identifier}}(:)(?!:)'
          captures:
            1: keyword.operator.conditional.ruby
        - include: after-operator
    - match: ':(?!:)'
      scope: keyword.operator.conditional.ruby
      push: after-operator
    - match: \;
      scope: punctuation.terminator.statement.ruby
      push: after-operator
    - match: ","
      scope: punctuation.separator.ruby
      push: after-operator
    - match: '\['
      scope: punctuation.section.array.ruby
      push: after-operator
    - match: \(
      scope: punctuation.definition.group.begin.ruby
      push: after-operator
    # Opening { is handled by "block" context to try and detect parameters
    - match: '\}'
      scope: punctuation.section.scope.ruby
    - match: '\]'
      scope: punctuation.section.array.ruby
    - match: \)
      scope: punctuation.definition.group.end.ruby
    - match: '\.\.\.?'
      scope: keyword.operator.ruby
      push: after-operator

  identifiers-accessors:
    # This consumes class/module access to prevent issues parsing : as part
    # of a ternary operator
    - match: '(::)(?={{identifier}}{{method_punctuation}})'
      scope: punctuation.accessor.ruby
      push:
        - include: well-known-methods
        - match: '{{identifier}}{{method_punctuation}}'
        - match: ''
          set: after-identifier
    # This consumes attribute access so we don't need a lookbehind for .
    - match: '(\.)(?={{identifier}}{{method_punctuation}})'
      scope: punctuation.accessor.ruby
      push:
        - include: well-known-methods
        - match: '{{identifier}}{{method_punctuation}}'
        - match: ''
          set: after-identifier
    # This consumes method names ending in punctuation so we don't need a lookbehind for ?, ! or =
    - match: '{{identifier}}{{method_punctuation}}'
    # This consumes module/class accessor so we don't need a lookbehind for ::
      push: after-identifier
    - match: '::|\.'
      scope: punctuation.accessor.ruby

  after-identifier:
    # Handles a : right after an identifier. In this case it can't be the
    # beginning of a symbol, so it must be part of a ternary operator
    - match: ':(?!:)'
      scope: keyword.operator.conditional.ruby
      pop: true
    - match: ''
      pop: true

  variables:
    - match: '(@)[a-zA-Z_]\w*'
      scope: variable.other.readwrite.instance.ruby
      captures:
        1: punctuation.definition.variable.ruby
    - match: '(@@)[a-zA-Z_]\w*'
      scope: variable.other.readwrite.class.ruby
      captures:
        1: punctuation.definition.variable.ruby
    - match: '(\$)[a-zA-Z_]\w*'
      scope: variable.other.readwrite.global.ruby
      captures:
        1: punctuation.definition.variable.ruby
    - match: '(\$)(!|@|&|`|''|\+|\d+|~|=|/|\\|,|;|\.|<|>|_|\*|\$|\?|:|"|-[0adFiIlpv])'
      scope: variable.other.readwrite.global.pre-defined.ruby
      captures:
        1: punctuation.definition.variable.ruby
    - match: '\b(ENV)\['
      captures:
        1: variable.other.constant.ruby
      push:
        - meta_scope: meta.environment-variable.ruby
        - match: '\]'
          pop: true
        - include: expressions
    - match: '(::)?(\b[[:upper:]]\w*)(?=((\.|::)[[:alpha:]_]|\[))'
      captures:
        1: punctuation.accessor.ruby
        2: support.class.ruby
    - match: '\b[[:upper:]]\w*\b'
      scope: variable.other.constant.ruby

  well-known-methods:
    - match: '\b(initialize|new|loop|include|extend|prepend|raise|fail|attr_reader|attr_writer|attr_accessor|attr|catch|throw|module_function|public|protected|private)\b(?![?!])'
      scope: keyword.other.special-method.ruby
    - match: \b(require|require_relative|gem)\b
      captures:
        1: keyword.other.special-method.ruby
      push:
        - meta_scope: meta.require.ruby
        - match: $|(?=#)
          captures:
            1: keyword.other.special-method.ruby
          pop: true
        - include: expressions
    # Conversion methods
    - match: |-
        (?x:
          \b(
            to_ary|
            to_a|
            to_c|
            to_enum|
            to_f|
            to_hash|
            to_h|
            to_int|
            to_io|
            to_i|
            to_proc|
            to_r|
            to_str|
            to_sym|
            to_s
          )\b
          (?![!?=])
        )
      scope: support.function.builtin.ruby
    # Methods that may be followed by a regex
    - match: |-
        (?x:
          \b(
            gsub!|
            sub!
          )(?=\s)
          |
          \b(
            assert_match|
            gsub|
            index|
            match|
            scan|
            sub
          )\b
        )
      scope: support.function.builtin.ruby
      push: try-regex
    # Methods from the Object class not handled elsewhere, ending in punctuation
    - match: |-
        (?x:
          \b(
            eql\?|
            instance_of\?|
            instance_variable_defined\?|
            is_a\?|
            kind_of\?|
            nil\?|
            respond_to\?|
            respond_to_missing\?|
            tainted\?|
            untrusted\?
          )
        )
      scope: support.function.builtin.ruby
    # Methods from the Object class not handled elsewhere
    - match: |-
        (?x:
          \b(
            class|
            clone|
            define_singleton_method|
            display|
            dup|
            enum_for|
            extend|
            freeze|
            frozen?|
            hash|
            inspect|
            instance_variable_get|
            instance_variable_set|
            instance_variables|
            itself|
            method|
            methods|
            object_id|
            private_methods|
            protected_methods|
            public_method|
            public_methods|
            public_send|
            remove_instance_variable|
            send|
            singleton_class|
            singleton_method|
            singleton_methods|
            taint|
            tap|
            trust|
            untaint|
            untrust
          )\b
          (?![!?=])
        )
      scope: support.function.builtin.ruby

    # Methods from the Kernel class not handled elsewhere, ending in punctuation
    - match: |-
        (?x:
          \b(
            autoload\?|
            iterator\?|
            exit!
          )
        )
      scope: support.function.builtin.ruby
    # Methods from the Kernel class not handled elsewhere
    - match: |-
        (?x:
          \b(
            Array|
            Complex|
            Float|
            Hash|
            Integer|
            Rational|
            String|
            __callee__|
            __dir__|
            __method__|
            abort|
            at_exit|
            autoload|
            binding|
            callcc|
            caller|
            caller_locations|
            chomp|
            chop|
            eval|
            exec|
            exit|
            fork|
            format|
            gets|
            global_variables|
            gsub|
            lambda|
            load|
            local_variables|
            open|
            p|
            print|
            printf|
            proc|
            putc|
            puts|
            rand|
            readline|
            readlines|
            require|
            require_relative|
            select|
            set_trace_func|
            sleep|
            spawn|
            sprintf|
            srand|
            sub|
            syscall|
            system|
            test|
            trace_var|
            trap|
            untrace_var|
            warn
          )\b
          (?![!?=])
        )
      scope: support.function.builtin.ruby
    # Methods from the Kernel class not handled elsewhere, ending in punctuation
    - match: |-
        (?x:
          \b(
            class_variable_defined\?|
            const_defined\?|
            include\?|
            instance_methods\?|
            method_defined\?|
            private_method_defined\?|
            protected_method_defined\?|
            public_method_defined\?|
            singleton_class\?
          )
        )
      scope: support.function.builtin.ruby
    # Methods from the Module class not handled elsewhere
    - match: |-
        (?x:
          \b(
            ancestors|
            append_features|
            class_eval|
            class_exec|
            class_variable_get|
            class_variable_set|
            class_variables|
            const_get|
            const_missing|
            const_set|
            constants|
            define_method|
            extend_object|
            extended|
            freeze|
            included|
            included_modules|
            inspect|
            method_added|
            method_removed|
            method_undefined|
            module_eval|
            module_exec|
            name|
            prepend_features|
            prepended|
            private_class_method|
            private_constant|
            private_instance_methods|
            protected_instance_methods|
            public_class_method|
            public_constant|
            public_instance_method|
            public_instance_methods|
            refine|
            remove_class_variable|
            remove_const|
            remove_method|
            undef_method|
            using
          )\b
          (?![!?=])
        )
      scope: support.function.builtin.ruby

  method:
    - match: \b(def)\b
      scope: meta.function.ruby keyword.control.def.ruby
      push:
        - meta_content_scope: meta.function.ruby
        - match: '(self)(\.)({{identifier}}{{method_punctuation}}|===?|>[>=]?|<=>|<[<=]?|[%&`/\|]|\*\*?|=?~|[-+]@?|\[\]=?)'
          captures:
            1: variable.language.ruby
            2: punctuation.accessor.ruby
            3: entity.name.function.ruby
          set: method-parameters-start
        - match: '===?|>[>=]?|<=>|<[<=]?|[%&`/\|]|\*\*?|=?~|[-+]@?|\[\]=?'
          scope: entity.name.function.ruby
          set: method-parameters-start
        - match: '(?:({{identifier}})(::|\.))?{{identifier}}{{method_punctuation}}'
          scope: entity.name.function.ruby
          captures:
            1: support.other.namespace.ruby
            2: punctuation.accessor.ruby
          set: method-parameters-start
        - match: '$'
          pop: true
        - match: '(?=\S)'
          pop: true

  method-parameters-start:
    - meta_content_scope: meta.function.ruby
    - match: '(?=\()'
      set:
        - meta_content_scope: meta.function.parameters.ruby
        - match: '\('
          scope: punctuation.definition.group.begin.ruby
          set: method-parameters
    # No parameters
    - match: '(?=$|;|#)'
      pop: true
    # No parentheses around parameters
    - match: '(?=[[:alpha:]_*])'
      set: method-bare-parameters

  method-parameters:
    - meta_content_scope: meta.function.parameters.ruby
    - match: '\)'
      scope: meta.function.parameters.ruby punctuation.definition.group.end.ruby
      pop: true
    - match: '{{identifier}}'
      scope: variable.parameter.ruby
    - match: ','
      scope: punctuation.separator.ruby
    - match: '\*'
      scope: keyword.operator.splat.ruby
    - match: '&'
      scope: keyword.operator.ruby
    # De-structuring
    - match: \(
      scope: punctuation.definition.group.begin.ruby
      push:
        - match: \)
          scope: punctuation.definition.group.end.ruby
          pop: true
        - match: '{{identifier}}'
          scope: variable.parameter.ruby
        - match: ','
          scope: punctuation.separator.ruby
        - match: '\*'
          scope: keyword.operator.splat.ruby
    # Default values
    - match: (?==)
      set:
        - meta_content_scope: meta.function.parameters.default-value.ruby
        - match: '='
          scope: keyword.operator.assignment.ruby
          set:
            - meta_content_scope: meta.function.parameters.default-value.ruby
            - match: '(?=[,\)])'
              set: method-parameters
            - include: nest-all
            - include: expressions
    # Keyword parameter (with default value support)
    - match: (?=:)
      set:
        - meta_content_scope: meta.function.parameters.default-value.ruby
        - match: ':'
          scope: punctuation.separator.ruby
          set:
            - meta_content_scope: meta.function.parameters.default-value.ruby
            - match: '(?=[,\)])'
              set: method-parameters
            - include: nest-all
            - include: expressions

  # When no parentheses are placed around the parameters
  method-bare-parameters:
    - meta_content_scope: meta.function.parameters.ruby
    - match: '(?=$|;|#)'
      pop: true
    - match: '{{identifier}}'
      scope: variable.parameter.ruby
    - match: ','
      scope: punctuation.separator.ruby
    - match: '\*'
      scope: keyword.operator.splat.ruby
    - match: '&'
      scope: keyword.operator.ruby
    # Default values
    - match: (?==)
      set:
        - meta_content_scope: meta.function.parameters.default-value.ruby
        - match: '='
          scope: punctuation.operator.assignment.ruby
          set:
            - meta_content_scope: meta.function.parameters.default-value.ruby
            - match: '(?=$|[,;])'
              set: method-bare-parameters
            - include: nest-all
            - include: expressions
    # Keyword parameter (with default value support)
    - match: (?=:)
      set:
        - meta_content_scope: meta.function.parameters.default-value.ruby
        - match: ':'
          scope: punctuation.separator.ruby
          set:
            - meta_content_scope: meta.function.parameters.default-value.ruby
            - match: '(?=$|[,;])'
              set: method-bare-parameters
            - include: nest-all
            - include: expressions

  strings:
    - include: early-strings
    - include: regexes
    - include: late-strings

  early-strings:
    # single quoted string (does not allow interpolation)
    - match: "'"
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.single.ruby
        - match: "'"
          scope: punctuation.definition.string.end.ruby
          pop: true
        - match: \\'|\\\\
          scope: constant.character.escape.ruby
        - include: string-placeholder
    # double quoted string (allows for interpolation)
    - match: '"'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.double.ruby
        - match: '"'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: string-placeholder
    # execute string (allows for interpolation)
    - match: "`"
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.interpolated.ruby
        - match: "`"
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
    # execute string (allow for interpolation)
    - match: '%x\{'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.interpolated.ruby
        - match: '\}'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-curly-i
    # execute string (allow for interpolation)
    - match: '%x\['
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.interpolated.ruby
        - match: '\]'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-brackets-i
    # execute string (allow for interpolation)
    - match: '%x\<'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.interpolated.ruby
        - match: \>
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-ltgt-i
    # execute string (allow for interpolation)
    - match: '%x\('
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.interpolated.ruby
        - match: \)
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-parens-i
    # execute string (allow for interpolation)
    - match: '%x([^\w])'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.interpolated.ruby
        - match: \1
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char

  late-strings:
    # literal capable of interpolation ()
    - match: '%[QWI]?\('
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.upper.ruby
        - match: \)
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-parens-i
    # "literal capable of interpolation []"
    - match: '%[QWI]?\['
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.upper.ruby
        - match: '\]'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-brackets-i
    # literal capable of interpolation <>
    - match: '%[QWI]?\<'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.upper.ruby
        - match: \>
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-ltgt-i
    # literal capable of interpolation -- {}
    - match: '%[QWI]?\{'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.double.ruby.mod
        - match: '\}'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-curly-i
    # literal capable of interpolation -- wildcard
    - match: '%[QWI]([^\w])'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.upper.ruby
        - match: \1
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
    # literal capable of interpolation -- wildcard
    - match: '%([^\w\s=])'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.other.ruby
        - match: \1
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
    # literal incapable of interpolation -- ()
    - match: '%[qwsi]\('
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.lower.ruby
        - match: \)
          scope: punctuation.definition.string.end.ruby
          pop: true
        - match: \\\)|\\\\
          scope: constant.character.escape.ruby
        - include: nest-parens
    # literal incapable of interpolation -- <>
    - match: '%[qwsi]\<'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.lower.ruby
        - match: \>
          scope: punctuation.definition.string.end.ruby
          pop: true
        - match: \\\>|\\\\
          scope: constant.character.escape.ruby
        - include: nest-ltgt
    # literal incapable of interpolation -- []
    - match: '%[qwsi]\['
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.lower.ruby
        - match: '\]'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - match: '\\\]|\\\\'
          scope: constant.character.escape.ruby
        - include: nest-brackets
    # literal incapable of interpolation -- {}
    - match: '%[qwsi]\{'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.lower.ruby
        - match: '\}'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - match: '\\\}|\\\\'
          scope: constant.character.escape.ruby
        - include: nest-curly
    # literal incapable of interpolation -- wildcard
    - match: '%[qwsi]([^\w])'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.quoted.other.literal.lower.ruby
        - match: \1
          scope: punctuation.definition.string.end.ruby
          pop: true
        # Cant be named because its not necessarily an escape
        - match: \\.

  after-keyword:
    - include: try-regex

  after-operator:
    - include: try-regex

  try-regex:
    # Generally for multiline regexes, one of the %r forms below will be used,
    # so we bail out if we can't find a second / on the current line
    - match: '(?=\s*/[^/]*$)'
      pop: true
    - match: '\s*(/)(?![*+{}?])'
      captures:
        1: string.regexp.classic.ruby punctuation.definition.string.ruby
      push:
        - meta_content_scope: string.regexp.classic.ruby
        - match: "(/)([eimnosux]*)"
          scope: string.regexp.classic.ruby
          captures:
            1: punctuation.definition.string.ruby
            2: keyword.other.ruby
          pop: true
        - include: regex-sub
    - match: ''
      pop: true

  regexes:
    # Needs higher precedence than regular expressions.
    - match: /=
      scope: keyword.operator.assignment.augmented.ruby
    - match: '(?=^\s*/)'
      push: try-regex
    - match: '(?=/\s*[^[:alnum:](\s])'
      push: try-regex
    # regular expressions (literal)
    - match: '%r\{'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.regexp.mod-r.ruby
        - match: '\}[eimnosux]*'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: regex-sub
        - include: nest-curly-r
    # regular expressions (literal)
    - match: '%r\['
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.regexp.mod-r.ruby
        - match: '\][eimnosux]*'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: regex-sub
        - include: nest-brackets-r
    # regular expressions (literal)
    - match: '%r\('
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.regexp.mod-r.ruby
        - match: '\)[eimnosux]*'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: regex-sub
        - include: nest-parens-r
    # regular expressions (literal)
    - match: '%r\<'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.regexp.mod-r.ruby
        - match: '\>[eimnosux]*'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: regex-sub
        - include: nest-ltgt-r
    # regular expressions (literal)
    - match: '%r([^\w])'
      scope: punctuation.definition.string.begin.ruby
      push:
        - meta_scope: string.regexp.mod-r.ruby
        - match: '\1[eimnosux]*'
          scope: punctuation.definition.string.end.ruby
          pop: true
        - include: regex-sub

  regex-sub:
    - include: interpolated-ruby
    - include: escaped-char
    - match: '(\{)\d+(,\d+)?(\})'
      scope: string.regexp.arbitrary-repetition.ruby
      captures:
        1: punctuation.definition.arbitrary-repetition.ruby
        3: punctuation.definition.arbitrary-repetition.ruby
    - match: '\[(?:\^?\])?'
      scope: punctuation.definition.character-class.ruby
      push:
        - meta_scope: string.regexp.character-class.ruby
        - match: '\]'
          scope: punctuation.definition.character-class.ruby
          pop: true
        - include: escaped-char
    - match: \(
      scope: punctuation.definition.group.ruby
      push:
        - meta_scope: string.regexp.group.ruby
        - match: \)
          scope: punctuation.definition.group.ruby
          pop: true
        - include: regex-sub
    # We are restrictive in what we allow to go after the comment character to
    # avoid false positives, since the availability of comments depend on regexp
    # flags.
    - match: '(?:^|\s)(#)\s[[a-zA-Z0-9,. \t?!-][^\x{00}-\x{7F}]]*$'
      scope: comment.line.number-sign.ruby
      captures:
        1: punctuation.definition.comment.ruby

  nest-brackets-r:
    - match: '\['
      scope: punctuation.section.scope.ruby
      push:
        - match: '\]'
          scope: punctuation.section.scope.ruby
          pop: true
        - include: regex-sub
        - include: nest-brackets-r
  nest-curly-r:
    - match: '\{'
      scope: punctuation.section.scope.ruby
      push:
        - match: '\}'
          scope: punctuation.section.scope.ruby
          pop: true
        - include: regex-sub
        - include: nest-curly-r
  nest-ltgt-r:
    - match: \<
      scope: punctuation.section.scope.ruby
      push:
        - match: \>
          scope: punctuation.section.scope.ruby
          pop: true
        - include: regex-sub
        - include: nest-ltgt-r
  nest-parens-r:
    - match: \(
      scope: punctuation.section.scope.ruby
      push:
        - match: \)
          scope: punctuation.section.scope.ruby
          pop: true
        - include: regex-sub
        - include: nest-parens-r

  nest-brackets:
    - match: '\['
      scope: punctuation.section.scope.ruby
      push:
        - match: '\]'
          scope: punctuation.section.scope.ruby
          pop: true
        - include: nest-brackets
  nest-curly:
    - match: '\{'
      scope: punctuation.section.scope.ruby
      push: [nest-curly-inner, maybe-block-parameters]
  nest-curly-inner:
    - match: '\}'
      scope: punctuation.section.scope.ruby
      pop: true
    - include: nest-curly
  nest-ltgt:
    - match: \<
      scope: punctuation.section.scope.ruby
      push:
        - match: \>
          scope: punctuation.section.scope.ruby
          pop: true
        - include: nest-ltgt
  nest-parens:
    - match: \(
      scope: punctuation.section.scope.ruby
      push:
        - match: \)
          scope: punctuation.section.scope.ruby
          pop: true
        - include: nest-parens

  string-placeholder:
    # %[flags][width][.precision]type
    #
    # A format sequence consists of a percent sign, followed by optional
    # flags, width, and precision indicators, then terminated with a field
    # type character.
    #
    # Also this is used for time format in strftime.
    - match: |-
        (?x)%
        ([#0\- +\*]|(\d+\$))*                       # flags
        (-?\d+)?                                    # minimum field width
        (\.(\d+)?)?                                 # precision
        [diouxXDOUeEfFgGaAcCsSpnvtTbByYhHmMzZ%]     # conversion type
      scope: constant.other.placeholder.ruby

  escaped-char:
    - match: '\\(?:[0-7]{1,3}|x[\da-fA-F]{1,2}|.)'
      scope: constant.character.escape.ruby

  interpolated-ruby:
    - match: '(#\{)(\})'
      scope: punctuation.section.embedded.ruby
      captures:
        1: source.ruby.embedded.source
        2: source.ruby.embedded.source.empty
    - match: '#\{'
      scope: punctuation.section.embedded.ruby
      push:
        - meta_scope: source.ruby.embedded.source
        - match: '\}'
          scope: punctuation.section.embedded.ruby
          pop: true
        - include: nest-curly-expressions
        - include: expressions
    - match: '(#@)[[:alpha:]_]\w*'
      scope: variable.other.readwrite.instance.ruby
      captures:
        1: punctuation.definition.variable.ruby
    - match: '(#@@)[[:alpha:]_]\w*'
      scope: variable.other.readwrite.class.ruby
      captures:
        1: punctuation.definition.variable.ruby
    - match: '(#\$)[[:alpha:]_]\w*'
      scope: variable.other.readwrite.global.ruby
      captures:
        1: punctuation.definition.variable.ruby

  nest-curly-expressions:
    - match: '\{'
      scope: punctuation.section.scope.ruby
      push: [nest-curly-expressions-inner, maybe-block-parameters]
  nest-curly-expressions-inner:
    - match: '\}'
      scope: punctuation.section.scope.ruby
      pop: true
    - include: nest-curly-expressions
    - include: expressions

  nest-all:
    - match: '\('
      scope: punctuation.definition.group.begin.ruby
      push:
        - match: '\)'
          scope: punctuation.definition.group.end.ruby
          pop: true
        - include: nest-all
        - include: expressions
    - match: '\{'
      scope: punctuation.section.scope.ruby
      push: [nest-all-inner, maybe-block-parameters]
    - match: '\['
      scope: punctuation.section.array.ruby
      push:
        - match: '\]'
          scope: punctuation.section.array.ruby
          pop: true
        - include: nest-all
        - include: expressions
  nest-all-inner:
    - match: '\}'
      scope: punctuation.section.scope.ruby
      pop: true
    - include: nest-all
    - include: expressions

  nest-brackets-i:
    - match: '\['
      scope: punctuation.section.scope.ruby
      push:
        - match: '\]'
          scope: punctuation.section.scope.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-brackets-i
  nest-curly-i:
    - match: '\{'
      scope: punctuation.section.scope.ruby
      push: [nest-curly-i-inner, maybe-block-parameters]
  nest-curly-i-inner:
    - match: '\}'
      scope: punctuation.section.scope.ruby
      pop: true
    - include: interpolated-ruby
    - include: escaped-char
    - include: nest-curly-i
  nest-ltgt-i:
    - match: \<
      scope: punctuation.section.scope.ruby
      push:
        - match: \>
          scope: punctuation.section.scope.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-ltgt-i
  nest-parens-i:
    - match: \(
      scope: punctuation.section.scope.ruby
      push:
        - match: \)
          scope: punctuation.section.scope.ruby
          pop: true
        - include: interpolated-ruby
        - include: escaped-char
        - include: nest-parens-i

  heredocs:
    # heredoc with embedded HTML and indented terminator
    - match: '(<<[-~]"?((?:[_\w]+_|)HTML)\b"?)'
      scope: punctuation.definition.string.begin.ruby
      push: [heredoc-html, trailing-heredoc-start]
    # heredoc with embedded SQL and indented terminator
    - match: '(<<[-~]"?((?:[_\w]+_|)SQL)\b"?)'
      scope: punctuation.definition.string.begin.ruby
      push: [heredoc-sql, trailing-heredoc-start]
    # heredoc with embedded css and indented terminator
    - match: '(<<[-~]"?((?:[_\w]+_|)CSS)\b"?)'
      scope: punctuation.definition.string.begin.ruby
      push: [heredoc-css, trailing-heredoc-start]
    # heredoc with embedded javascript and indented terminator
    - match: '(<<[-~]"?((?:[_\w]+_|)(?:JS|JAVASCRIPT))\b"?)'
      scope: punctuation.definition.string.begin.ruby
      push: [heredoc-js, trailing-heredoc-start]
    # heredoc with embedded ruby and indented terminator
    - match: '(<<[-~]"?((?:[_\w]+_|)RUBY)\b"?)'
      scope: punctuation.definition.string.begin.ruby
      push: [heredoc-ruby, trailing-heredoc-start]
    # Escaped to prevent recursion?
    # heredoc with embedded shell and indented terminator
    # - match: '(<<[-~]("?)((?:[_\w]+_|)(?:SH|SHELL))\b\1)'
    #   scope: punctuation.definition.string.begin.ruby
    #   push: [heredoc-shell, trailing-heredoc-start]
    - match: (\=)\s*(<<(\w+))
      captures:
        1: keyword.operator.assignment.ruby
        2: punctuation.definition.string.begin.ruby
      push: [heredoc-assign, trailing-heredoc-no-embedding-start]
    # heredoc with indented terminator
    - match: '(<<[-~](\w+))'
      scope: punctuation.definition.string.begin.ruby
      push: [heredoc-plain, trailing-heredoc-no-embedding-start]

  heredoc-html:
    - meta_scope: string.unquoted.embedded.html.ruby
    - meta_content_scope: text.html.embedded.ruby
    - match: ^\s*\2$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: scope:text.html.basic
    - include: interpolated-ruby
    - include: escaped-char

  heredoc-sql:
    - meta_scope: string.unquoted.embedded.sql.ruby
    - meta_content_scope: text.sql.embedded.ruby
    - match: ^\s*\2$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: scope:source.sql
    - include: interpolated-ruby
    - include: escaped-char

  heredoc-css:
    - meta_scope: string.unquoted.embedded.css.ruby
    - meta_content_scope: text.css.embedded.ruby
    - match: ^\s*\2$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: 'scope:source.css'
    - include: interpolated-ruby
    - include: escaped-char

  heredoc-js:
    - meta_scope: string.unquoted.embedded.js.ruby
    - meta_content_scope: text.js.embedded.ruby
    - match: ^\s*\2$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: 'scope:source.js'
    - include: interpolated-ruby
    - include: escaped-char

  heredoc-ruby:
    - meta_scope: string.unquoted.embedded.ruby.ruby
    - meta_content_scope: text.ruby.embedded.ruby
    - match: ^\s*\2$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: interpolated-ruby
    - include: escaped-char
    - include: expressions

  #heredoc-shell:
  #  - meta_scope: string.unquoted.embedded.shell.ruby
  #  - meta_content_scope: text.shell.embedded.ruby
  #  - match: ^\s*\2$
  #    scope: punctuation.definition.string.end.ruby
  #    pop: true
  #  - include: Shell-Unix-Generic.sublime-syntax
  #  - include: interpolated-ruby
  #  - include: escaped-char

  # This prevents clear_scopes from applying to the push token
  trailing-heredoc-start:
    - match: ''
      set: trailing-heredoc

  trailing-heredoc:
    - clear_scopes: 2
    - match: '$'
      pop: true
    - include: expressions

  heredoc-assign:
    - meta_scope: string.unquoted.heredoc.ruby
    - match: ^\s*\3$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: interpolated-ruby
    - include: escaped-char

  heredoc-plain:
    - meta_scope: string.unquoted.heredoc.ruby
    - match: ^\s*\2$
      scope: punctuation.definition.string.end.ruby
      pop: true
    - include: interpolated-ruby
    - include: escaped-char

  # This prevents clear_scopes from applying to the push token
  trailing-heredoc-no-embedding-start:
    - match: ''
      set: trailing-heredoc-no-embedding

  trailing-heredoc-no-embedding:
    - clear_scopes: 1
    - match: '$'
      pop: true
    - include: expressions

  data-section:
    - match: ^__END__\n
      scope: string.unquoted.program-block.ruby
      push:
        - meta_content_scope: text.plain
        - match: (?=<?xml|<(?i:html\b)|!DOCTYPE (?i:html\b))
          push:
            - meta_scope: text.html.embedded.ruby
            - include: scope:text.html.basic