class SyntaxSuggest::CodeLine

Represents a single line of code of a given source file

This object contains metadata about the line such as amount of indentation, if it is empty or not, and lexical data, such as if it has an end or a keyword in it.

Visibility of lines can be toggled off. Marking a line as invisible indicates that it should not be used for syntax checks. It’s functionally the same as commenting it out.

Example:

line = CodeLine.from_source("def foo\n").first
line.number => 1
line.empty? # => false
line.visible? # => true
line.mark_invisible
line.visible? # => false

Constants

TRAILING_SLASH

Attributes

indent [R]

index [R]

line [R]

line_number [R]

number [R]

original [R]

When the code line is marked invisible we retain the original value of it’s line this is useful for debugging and for showing extra context

DisplayCodeWithLineNumbers will render all lines given to it, not just visible lines, it uses the original method to obtain them.

tokens [R]

Public Class Methods

clean_comments! (source, comments)

Source

# File lib/syntax_suggest/code_line.rb, line 65
def self.clean_comments!(source, comments)
  # Iterate backwards since we are modifying the source in place and must preserve
  # the offsets. Prism comments are sorted by their location in the source.
  comments.reverse_each do |comment|
    next if comment.trailing?
    source.bytesplice(comment.location.start_offset, comment.location.length, "")
  end
end

Remove comments that apear on their own in source. They will never be the cause of syntax errors and are just visual noise. Example:

source = +<<~RUBY
  # Comment-only line
  foo # Inline comment
RUBY
CodeLine.clean_comments!(source, Prism.parse(source).comments)
source # => "\nfoo # Inline comment\n"

from_source (source)

Source

# File lib/syntax_suggest/code_line.rb, line 29
def self.from_source(source)
  source = +source
  parse_result = Prism.parse_lex(source)
  ast, tokens = parse_result.value

  clean_comments!(source, parse_result.comments)

  visitor = Visitor.new
  visitor.visit(ast)
  tokens.sort_by! { |token, _state| token.location.start_line }

  prev_token = nil
  tokens.map! do |token, _state|
    prev_token = Token.new(token, prev_token, visitor)
  end

  tokens_for_line = tokens.each_with_object(Hash.new { |h, k| h[k] = [] }) { |token, hash| hash[token.line] << token }
  source.lines.map.with_index do |line, index|
    CodeLine.new(
      line: line,
      index: index,
      tokens: tokens_for_line[index + 1],
      consecutive: visitor.consecutive_lines.include?(index + 1)
    )
  end
end

Returns an array of CodeLine objects from the source string

new (line:, index:, tokens:, consecutive:)

Source

# File lib/syntax_suggest/code_line.rb, line 75
def initialize(line:, index:, tokens:, consecutive:)
  @tokens = tokens
  @line = line
  @index = index
  @consecutive = consecutive
  @original = line
  @line_number = @index + 1
  strip_line = line.dup
  strip_line.lstrip!

  @indent = if (@empty = strip_line.empty?)
    line.length - 1 # Newline removed from strip_line is not "whitespace"
  else
    line.length - strip_line.length
  end

  set_kw_end
end

Public Instance Methods

<=> (other)

Source

# File lib/syntax_suggest/code_line.rb, line 184
def <=>(other)
  index <=> other.index
end

Comparison operator, needed for equality and sorting

consecutive? ()

Source

# File lib/syntax_suggest/code_line.rb, line 191
def consecutive?
  @consecutive
end

Can this line be logically joined together with the following line? Determined by walking the AST

empty? ()

Source

# File lib/syntax_suggest/code_line.rb, line 149
def empty?
  @empty
end

An empty? line is one that was originally left empty in the source code, while a “hidden” line is one that we’ve since marked as “invisible”

hidden? ()

Source

# File lib/syntax_suggest/code_line.rb, line 142
def hidden?
  !visible?
end

Opposite or visible? (note: different than empty?)

indent_index ()

Source

# File lib/syntax_suggest/code_line.rb, line 106
def indent_index
  @indent_index ||= [indent, index]
end

Used for stable sort via indentation level

Ruby’s sort is not “stable” meaning that when multiple elements have the same value, they are not guaranteed to return in the same order they were put in.

So when multiple code lines have the same indentation level, they’re sorted by their index value which is unique and consistent.

This is mostly needed for consistency of the test suite

is_end? ()

Source

# File lib/syntax_suggest/code_line.rb, line 121
def is_end?
  @is_end
end

Returns true if the code line is determined to contain an end keyword

is_kw? ()

Source

# File lib/syntax_suggest/code_line.rb, line 115
def is_kw?
  @is_kw
end

Returns true if the code line is determined to contain a keyword that matches with an end

For example: def, do, begin, ensure, etc.

mark_invisible ()

Source

# File lib/syntax_suggest/code_line.rb, line 130
def mark_invisible
  @line = ""
end

Used to hide lines

The search alorithm will group lines into blocks then if those blocks are determined to represent valid code they will be hidden

not_empty? ()

Source

# File lib/syntax_suggest/code_line.rb, line 154
def not_empty?
  !empty?
end

Opposite of empty? (note: different than visible?)

to_s ()

Source

# File lib/syntax_suggest/code_line.rb, line 167
def to_s
  line
end

Renders the given line

Also allows us to represent source code as an array of code lines.

When we have an array of code line elements calling join on the array will call to_s on each element, which essentially converts it back into it’s original source string.

trailing_slash? ()

Source

# File lib/syntax_suggest/code_line.rb, line 204
def trailing_slash?
  return unless (last = @tokens.last)
  @line.byteindex(TRAILING_SLASH, last.location.end_column) != nil
end

Determines if the given line has a trailing slash. Simply check if the line contains a backslash after the content of the last token.

lines = CodeLine.from_source(<<~EOM)
  it "foo" \
EOM
expect(lines.first.trailing_slash?).to eq(true)

visible? ()

Source

# File lib/syntax_suggest/code_line.rb, line 137
def visible?
  !line.empty?
end

Means the line was marked as “invisible” Confusingly, “empty” lines are visible…they just don’t contain any source code other than a newline (“\n”).

Private Instance Methods

set_kw_end ()

Source

# File lib/syntax_suggest/code_line.rb, line 209
        def set_kw_end
  kw_count = 0
  end_count = 0

  @tokens.each do |token|
    kw_count += 1 if token.is_kw?
    end_count += 1 if token.is_end?
  end

  @is_kw = (kw_count - end_count) > 0
  @is_end = (end_count - kw_count) > 0
end