class SyntaxTree::LanguageServer::InlayHints

This class provides inlay hints for the language server. For more information, see the spec here: github.com/microsoft/language-server-protocol/issues/956.

Attributes

hints [R]

stack [R]

Public Class Methods

new ()

Source

# File lib/syntax_tree/language_server.rb, line 43
def initialize
  @stack = []
  @hints = []
end

Public Instance Methods

visit (node)

Source

# File lib/syntax_tree/language_server.rb, line 48
def visit(node)
  stack << node
  result = super
  stack.pop
  result
end

Calls superclass method

visit_assign (node)

Source

# File lib/syntax_tree/language_server.rb, line 67
def visit_assign(node)
  parentheses(node.location) if stack[-2].is_a?(Params)
  super
end

Adds parentheses around assignments contained within the default values of parameters. For example,

def foo(a = b = c)
end

becomes

def foo(a = ₍b = c₎)
end

Calls superclass method

visit_binary (node)

Source

# File lib/syntax_tree/language_server.rb, line 81
def visit_binary(node)
  case stack[-2]
  when Assign, OpAssign
    parentheses(node.location)
  when Binary
    parentheses(node.location) if stack[-2].operator != node.operator
  end

  super
end

Adds parentheses around binary expressions to make it clear which subexpression will be evaluated first. For example,

a + b * c

becomes

a + ₍b * c₎

Calls superclass method

visit_if_op (node)

Source

# File lib/syntax_tree/language_server.rb, line 102
def visit_if_op(node)
  case stack[-2]
  when Assign, Binary, IfOp, OpAssign
    parentheses(node.location)
  end

  super
end

Adds parentheses around ternary operators contained within certain expressions where it could be confusing which subexpression will get evaluated first. For example,

a ? b : c ? d : e

becomes

a ? b : ₍c ? d : e₎

Calls superclass method

visit_rescue (node)

Source

# File lib/syntax_tree/language_server.rb, line 124
def visit_rescue(node)
  if node.exception.nil?
    hints << Hint.new(
      line: node.location.start_line - 1,
      character: node.location.start_column + "rescue".length,
      label: " StandardError"
    )
  end

  super
end

Adds the implicitly rescued StandardError into a bare rescue clause. For example,

begin
rescue
end

becomes

begin
rescue StandardError
end

Calls superclass method

visit_unary (node)

Source

# File lib/syntax_tree/language_server.rb, line 145
def visit_unary(node)
  if stack[-2].is_a?(Binary) && (node.operator == "-")
    parentheses(node.location)
  end

  super
end

Adds parentheses around unary statements using the - operator that are contained within Binary nodes. For example,

-a + b

becomes

₍-a₎ + b

Calls superclass method