Class: SyntaxTree::LanguageServer::InlayHints

Inherits:
Visitor
  • Object
show all
Defined in:
lib/syntax_tree/language_server/inlay_hints.rb

Overview

This class provides inlay hints for the language server. It is loosely designed around the LSP spec, but existed before the spec was finalized so is a little different for now.

For more information, see the spec here: github.com/microsoft/language-server-protocol/issues/956.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Visitor

#visit_all, #visit_child_nodes, visit_method, visit_methods

Constructor Details

#initialize ⇒ InlayHints

Returns a new instance of InlayHints.



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 15

def initialize
  @stack = []
  @before = Hash.new { |hash, key| hash[key] = +"" }
  @after = Hash.new { |hash, key| hash[key] = +"" }
end

Instance Attribute Details

#after ⇒ Object (readonly)

Returns the value of attribute after.



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 13

def after
  @after
end

#before ⇒ Object (readonly)

Returns the value of attribute before.



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 13

def before
  @before
end

#stack ⇒ Object (readonly)

Returns the value of attribute stack.



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 13

def stack
  @stack
end

Class Method Details

.find(program) ⇒ Object 



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 112

def self.find(program)
  visitor = new
  visitor.visit(program)
  visitor
end

Instance Method Details

#visit(node) ⇒ Object 



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 21

def visit(node)
  stack << node
  result = super
  stack.pop
  result
end

#visit_assign(node) ⇒ Object

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



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 39

def visit_assign(node)
  parentheses(node.location) if stack[-2].is_a?(Params)
end

#visit_binary(node) ⇒ Object

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

a + b * c

becomes

a + ₍b * c₎



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 52

def visit_binary(node)
  case stack[-2]
  in Assign | OpAssign
    parentheses(node.location)
  in Binary[operator: operator] if operator != node.operator
    parentheses(node.location)
  else
  end
end

#visit_if_op(node) ⇒ Object

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₎



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 72

def visit_if_op(node)
  if stack[-2] in Assign | Binary | IfOp | OpAssign
    parentheses(node.location)
  end
end

#visit_rescue(node) ⇒ Object

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

begin
rescue
end

becomes

begin
rescue StandardError
end



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 91

def visit_rescue(node)
  if node.exception.nil?
    after[node.location.start_char + "rescue".length] << " StandardError"
  end
end

#visit_unary(node) ⇒ Object

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

-a + b

becomes

₍-a₎ + b



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# File 'lib/syntax_tree/language_server/inlay_hints.rb', line 106

def visit_unary(node)
  if stack[-2].is_a?(Binary) && (node.operator == "-")
    parentheses(node.location)
  end
end