%YAML 1.2
#
# This syntax definition is based on the Terraform guide:
# https://www.terraform.io/docs/configuration/index.html
#
# As well as the HCL Native Syntax Spec:
# https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md
#
# For documentation on the .subline-syntax format:
# https://www.sublimetext.com/docs/3/syntax.html
#
# Regex's in this file support the Oniguruma regex engine:
# https://raw.githubusercontent.com/kkos/oniguruma/5.9.6/doc/RE
#
---
name: Terraform

# File Extensions:
#
# - ".tf": the standard file extension
#   https://www.terraform.io/docs/configuration/index.html#code-organization
#
# - ".tfvars": variables definitions file
#   https://www.terraform.io/docs/configuration/variables.html#variable-definitions-tfvars-files
#
# - ".hcl": non-terraform tools often use this HCL syntax, i.e. Vault
#   https://www.vaultproject.io/docs/configuration/
file_extensions:
  - tf
  - tfvars
  - hcl
scope: source.terraform

variables:
  # Identifiers: (UTF-8) (ID_Continue | '-')*;
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#identifiers
  identifer: \b(?!null|false|true)[[:alpha:]][[:alnum:]_-]*\b

  # Exponent: "e" or "E" followed by an optional sign
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#numeric-literals
  exponent: ([Ee][+-]?)

  # Character Escapes:
  #
  #   - \n: newline
  #   - \r: carriage return
  #   - \t: tab
  #   - \": quote
  #   - \\: backslash
  #   - \uNNNN: unicode char (NNNN is 4 hex digits)
  #   - \uNNNNNNNN: unicode char (NNNNNNNN us 8 digits)
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#template-expressions
  char_escapes: \\[nrt"\\]|\\u(\h{8}|\h{4})

  # Terraform Named Values
  #
  # https://www.terraform.io/docs/configuration/expressions.html#references-to-named-values
  named_values: var|local|module|data|path|terraform

  # Block types that are known to Terraform.
  #
  # resource: https://www.terraform.io/docs/configuration/resources.html
  # provider: https://www.terraform.io/docs/configuration/providers.html
  # variable: https://www.terraform.io/docs/configuration/variables.html
  # output: https://www.terraform.io/docs/configuration/outputs.html
  # locals: https://www.terraform.io/docs/configuration/locals.html
  # module: https://www.terraform.io/docs/configuration/modules.html
  # data: https://www.terraform.io/docs/configuration/data-sources.html
  # terraform: https://www.terraform.io/docs/configuration/terraform.html#terraform-block-syntax
  terraform_known_blocks: resource|provider|variable|output|locals|module|data|terraform

  # Terraform built-in type keywords
  #
  # https://www.terraform.io/docs/configuration/types.html#primitive-types
  # https://www.terraform.io/docs/configuration/types.html#dynamic-types-the-quot-any-quot-constraint
  terraform_type_keywords: any|string|number|bool

  # Built-In Functions
  #
  # https://www.terraform.io/docs/configuration/functions.html
  predeclared_funcs: abs|ceil|floor|log|max|min|pow|signum|chomp|format|formatlist|indent|join|lower|regex|regexall|replace|split|strrev|substr|title|trimspace|upper|chunklist|coalesce|coalescelist|compact|concat|contains|distinct|element|flatten|index|keys|length|list|lookup|map|matchkeys|merge|range|reverse|setintersection|setproduct|setunion|slice|sort|transpose|values|zipmap|base64decode|base64encode|base64gzip|csvdecode|jsondecode|jsonencode|urlencode|yamldecode|yamlencode|abspath|dirname|pathexpand|basename|file|fileexists|fileset|filebase64|templatefile|formatdate|timeadd|timestamp|base64sha256|base64sha512|bcrypt|filebase64sha256|filebase64sha512|filemd5|filemd1|filesha256|filesha512|md5|rsadecrypt|sha1|sha256|sha512|uuid|uuidv5|cidrhost|cidrnetmask|cidrsubnet|tobool|tolist|tomap|tonumber|toset|tostring

contexts:
  main:
    - include: comments
    - include: attribute_definition
    - include: imports
    - include: block
    - include: expressions

  comments:
    - include: inline_comments
    - include: block_comments

  # Expressions:
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#expression-terms
  expressions:
    - include: literal_values
    - include: operators
    - include: brackets
    - include: objects
    - include: attribute_access
    - include: functions
    - include: parens

  comma:
    - match: \,
      comment: Commas - used in certain expressions
      scope: punctuation.separator.terraform

  parens:
    - match: \(
      scope: punctuation.section.parens.begin.terraform
      comment: Parens - matched *after* function syntax
      push:
        - match: \)
          scope: punctuation.section.parens.end.terraform
          pop: true
        - include: expressions
        - match: "{{identifer}}"
          comment: Local Identifiers
          scope: variable.other.readwrite.terraform

  # Literal Values: Numbers, Language Constants, and Strings
  #
  #   Strings are _technically_ part of the "expression sub-language",
  #   but make the most sense to be part of this stack.
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#literal-values
  literal_values:
    - include: numeric_literals
    - include: language_constants
    - include: string_literals
    - include: heredoc
    - include: type_keywords
    - include: named_value_references

  named_value_references:
    - match: '\b({{named_values}})\b'
      comment: Constant values available only to Terraform.
      scope: support.constant.terraform

  type_keywords:
    - match: '\b({{terraform_type_keywords}})\b'
      comment: Type keywords known to Terraform.
      scope: storage.type.terraform

  # Inline Comments: begin at the operator, end at the end of the line.
  #
  # https://www.terraform.io/docs/configuration/syntax.html#comments
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#comments-and-whitespace
  inline_comments:
    - match: '#|//'
      comment: Inline Comments
      scope: punctuation.definition.comment.terraform
      push:
        - meta_scope: comment.line.terraform
        - match: $\n?
          scope: punctuation.definition.comment.terraform
          pop: true

  # Block comments: start and end delimiters for multi-line comments.
  #
  # https://www.terraform.io/docs/configuration/syntax.html#comments
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#comments-and-whitespace
  block_comments:
    - match: /\*
      comment: Block comments
      scope: punctuation.definition.comment.terraform
      push:
        - meta_scope: comment.block.terraform
        - match: \*/
          scope: punctuation.definition.comment.terraform
          pop: true

  # Language Constants: booleans and `null`.
  #
  # https://www.terraform.io/docs/configuration/expressions.html#literal-expressions
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#literal-values
  language_constants:
    - match: \b(true|false|null)\b
      comment: Language Constants
      scope: constant.language.terraform

  # Numbers: Integers, fractions and exponents
  #
  # https://www.terraform.io/docs/configuration/expressions.html#types-and-values
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#numeric-literals
  numeric_literals:
    - match: \b\d+({{exponent}})\d+\b
      comment: Integer, no fraction, optional exponent
      scope: constant.numeric.float.terraform
      captures:
        1: punctuation.separator.exponent.terraform
    - match: \b\d+(\.)\d+(?:({{exponent}})\d+)?\b
      comment: Integer, fraction, optional exponent
      scope: constant.numeric.float.terraform
      captures:
        1: punctuation.separator.decimal.terraform
        2: punctuation.separator.exponent.terraform
    - match: \b\d+\b
      comment: Integers
      scope: constant.numeric.integer.terraform

  # Strings:
  #
  # https://www.terraform.io/docs/configuration/expressions.html#types-and-values
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#template-expressions
  string_literals:
    - match: '"'
      comment: Strings
      scope: punctuation.definition.string.begin.terraform
      push:
        - meta_scope: string.quoted.double.terraform
        - match: '"'
          scope: punctuation.definition.string.end.terraform
          pop: true
        - include: string_interpolation
        - match: '{{char_escapes}}'
          comment: Character Escapes
          scope: constant.character.escape.terraform

  # String Interpolation: ("${" | "${~") Expression ("}" | "~}"
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#templates
  string_interpolation:
    - match: (\$|\%)\{
      comment: String interpolation
      scope: keyword.other.interpolation.begin.terraform
      push:
        - meta_scope: meta.interpolation.terraform
        - clear_scopes: 1 # Clear the string.* scope.
        - match: \}
          scope: keyword.other.interpolation.end.terraform
          pop: true
        - match: \~\s
          comment: Trim left whitespace
          scope: keyword.operator.template.left.trim.terraform
        - match: \s\~
          comment: Trim right whitespace
          scope: keyword.operator.template.right.trim.terraform
        - match: \b(if|else|endif|for|in|endfor)\b
          comment: if/else/endif and for/in/endfor directives
          scope: keyword.control.terraform
        - include: expressions

  # String Heredocs
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#template-expressions
  heredoc:
    - match: (\<\<\-?)\s*({{identifer}})\s*$
      comment: String Heredoc's
      captures:
        1: keyword.operator.heredoc.terraform
        2: keyword.control.heredoc.terraform
      push:
        - meta_content_scope: string.unquoted.heredoc.terraform
        - match: ^\s*\2\s*$
          comment: The heredoc token identifier (second capture above).
          scope: keyword.control.heredoc.terraform
          pop: true
        - include: string_interpolation

  # Operators:
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#operators-and-delimiters
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#operations
  operators:
    - match: \>\=   # >=
      scope: keyword.operator.terraform
    - match: \<\=   # <=
      scope: keyword.operator.terraform
    - match: \=\=   # ==
      scope: keyword.operator.terraform
    - match: \!\=   # !=
      scope: keyword.operator.terraform
    - match: \+     # +
      scope: keyword.operator.arithmetic.terraform
    - match: \-     # -
      scope: keyword.operator.arithmetic.terraform
    - match: \*     # *
      scope: keyword.operator.arithmetic.terraform
    - match: \/     # /
      scope: keyword.operator.arithmetic.terraform
    - match: \%     # %
      scope: keyword.operator.arithmetic.terraform
    - match: \&\&   # &&
      scope: keyword.operator.logical.terraform
    - match: \|\|   # ||
      scope: keyword.operator.logical.terraform
    - match: \!     # !
      scope: keyword.operator.logical.terraform
    - match: \>     # >
      scope: keyword.operator.terraform
    - match: \<     # <
      scope: keyword.operator.terraform
    - match: \?     # ?
      scope: keyword.operator.terraform
    - match: \.\.\. # ...
      scope: keyword.operator.terraform
    - match: "\\:"  # :
      scope: keyword.operator.terraform

  # Terraform "import" statements
  #
  # https://www.terraform.io/docs/import/usage.html
  imports:
    - match: \s*(terraform)\s*(import)\s*
      comment: Importing resources
      captures:
        1: support.constant.terraform
        2: keyword.control.import.terraform
      push:
        - match: \"
          comment: String literal label
          scope: punctuation.definition.string.begin.terraform
          push:
            - meta_scope: string.quoted.double.terraform
            - match: \"
              scope: punctuation.definition.string.end.terraform
              pop: true
        - match: "{{identifer}}"
          comment: Identifer label
          scope: entity.name.label.terraform
        - include: numeric_literals
        - include: attribute_access
        - match: $\n?
          comment: Pop at newline
          pop: true

  # Brackets: matches tuples and subscript notation
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#index-operator
  brackets:
    - match: \[
      scope: punctuation.section.brackets.begin.terraform
      push:
        - match: \]
          scope: punctuation.section.brackets.end.terraform
          pop: true
        - match: (\*)\]
          comment: Full-splat operator
          scope: punctuation.section.brackets.end.terraform
          captures:
            1: keyword.operator.splat.terraform
          pop: true
        - include: comma
        - include: comments
        - include: expressions
        - include: tuple_for_expression

  # Objects: collection values
  #
  #   Allows keys as identifiers, strings, and computed values wrapped in parens.
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#collection-values
  objects:
    - match: \{
      scope: punctuation.section.braces.begin.terraform
      push:
        - meta_scope: meta.braces.terraform
        - match: \}
          scope: punctuation.section.braces.end.terraform
          pop: true
        - include: object_for_expression
        - include: comments
        - match: '\s*({{identifer}})\s*(\=)\s*'
          comment: Literal, named object key
          captures:
            1: meta.mapping.key.terraform string.unquoted.terraform
            2: keyword.operator.terraform
          push: object_key_values
        - match: '((\").*(\"))\s*(\=)\s*'
          comment: String object key
          captures:
            1: meta.mapping.key.terraform string.quoted.double.terraform
            2: punctuation.definition.string.begin.terraform
            3: punctuation.definition.string.end.terraform
            4: keyword.operator.terraform
          push: object_key_values
        - match: \(
          comment: Computed object key (any expression between parens)
          scope: punctuation.section.parens.begin.terraform
          push:
            - meta_scope: meta.mapping.key.terraform
            - match: '(\))\s*(\=)\s*'
              captures:
                1: punctuation.section.parens.end.terraform
                2: keyword.operator.terraform
              set: object_key_values
            - include: expressions

  # Object key values: pop at comma, newline, and closing-bracket
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#collection-values
  object_key_values:
    - include: comments
    - include: expressions
    - match: \,
      comment: Pop scope on comma.
      scope: punctuation.separator.terraform
      pop: true
    - match: $\n?
      comment: Pop scope on EOL.
      pop: true
    - match: (?=\})
      comment: Lookahead (don't consume) and pop scope on a bracket.
      scope: punctuation.section.braces.end.terraform
      pop: true

  # Attribute Access: "." Identifier
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#attribute-access-operator
  attribute_access:
    - match: \.
      scope: keyword.operator.accessor.terraform
      push:
        - match: "{{identifer}}"
          comment: Attribute access
          scope: variable.other.member.terraform
          pop: true
        - match: \d+
          comment: Subscript
          scope: constant.numeric.integer.terraform
          pop: true
        - match: \*
          comment: Attribute-only splat
          scope: keyword.operator.splat.terraform
          pop: true

  # Attribute Definition: Identifier "=" Expression Newline
  #
  # The "=" operator cannot be immediately followed by "="
  # ">", as those are other operators, not attr definitions.
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#attribute-definitions
  attribute_definition:
    - match: (\()?({{identifer}})(\))?\s*(\=[^\=|\>])\s*
      comment: Identifier "=" with optional parens
      scope: variable.declaration.terraform
      captures:
        1: punctuation.section.parens.begin.terraform
        2: variable.other.readwrite.terraform
        3: punctuation.section.parens.end.terraform
        4: keyword.operator.assignment.terraform

  # Functions: Terraform builtins and unknown
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#functions-and-function-calls
  # https://www.terraform.io/docs/configuration/expressions.html#function-calls
  functions:
    - match: (({{predeclared_funcs}})|\b({{identifer}})\b)(\()
      comment: Built-in function calls
      captures:
        2: support.function.builtin.terraform
        3: variable.function.terraform
        4: punctuation.section.parens.begin.terraform
      push:
        - meta_scope: meta.function-call.terraform
        - match: \)
          scope: punctuation.section.parens.end.terraform
          pop: true
        - include: comments
        - include: expressions
        - include: comma

  # Tuple for-Expression:
  #
  # "[" "for" Identifier ("," Identifier)? "in" Expression ":" Expression ("if" Expression)? "]";
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#for-expressions
  # https://www.terraform.io/docs/configuration/expressions.html#for-expressions
  tuple_for_expression:
    - match: \bfor\b
      comment: for expression (arrays)
      scope: keyword.control.terraform
      set:
        - include: for_expression_body
        - match: \]
          scope: punctuation.section.brackets.end.terraform
          pop: true

  # Object for-Expression:
  #
  # "{" "for" Identifier ("," Identifier)? "in" Expression ":" Expression "=>" Expression "..."? ("if" Expression)? "}";
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#for-expressions
  # https://www.terraform.io/docs/configuration/expressions.html#for-expressions
  object_for_expression:
    - match: \bfor\b
      comment: for expression (arrays)
      scope: keyword.control.terraform
      set:
        - match: \=\>
          scope: storage.type.function.terraform
        - include: for_expression_body
        - match: \}
          scope: punctuation.section.braces.end.terraform
          pop: true

  # Shared body syntax for tuple and object for-expressions.
  # They require different `set` blocks because they are
  # pop'd with different characters and objects allow `=>`.
  for_expression_body:
    - match: \bin\b
      comment: in keyword
      scope: keyword.operator.word.terraform
    - match: \bif\b
      comment: if keyword
      scope: keyword.control.conditional.terraform
    - match: '\:'
      scope: keyword.operator.terraform
    - include: expressions
    - include: comments
    - include: comma
    - match: "{{identifer}}"
      comment: Local Identifiers
      scope: variable.other.readwrite.terraform

  # Blocks: Identifier (StringLit|Identifier)* "{" Newline Body "}" Newline;
  #
  # https://github.com/hashicorp/hcl2/blob/master/hcl/hclsyntax/spec.md#structural-elements
  block:
    - match: '(\b({{terraform_known_blocks}})\b|({{identifer}}))(?=[\s\"\-[:word:]]*(\{))'
      captures:
        2: storage.type.terraform
        3: entity.name.type.terraform
      push:
        - meta_scope: meta.type.terraform
        - match: \"
          comment: String literal label
          scope: punctuation.definition.string.begin.terraform
          push:
            - meta_scope: string.quoted.double.terraform
            - match: \"
              scope: punctuation.definition.string.end.terraform
              pop: true
        - match: "{{identifer}}"
          comment: Identifer label
          scope: entity.name.label.terraform
        - match: \{
          scope: punctuation.section.block.begin.terraform
          set:
            - meta_scope: meta.block.terraform
            - include: main
            - match: \}
              scope: punctuation.section.block.end.terraform
              pop: true