Module: CommandSearch::Lexer

Defined in:
lib/command_search/lexer.rb

Class Method Summary collapse

Class Method Details

.char_token(char) ⇒ Object 



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# File 'lib/command_search/lexer.rb', line 38

def char_token(char)
  { type: char_type(char), value: char }
end

.char_type(char) ⇒ Object

This currently does not support numbers with commas in them



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# File 'lib/command_search/lexer.rb', line 11

def char_type(char)
  case char
  when /["']/
    :quote
  when /[()]/
    :paren
  when /[<>]/
    :compare
  when /\s/
    :space
  when /\d/
    :number
  when '.'
    :period
  when '-'
    :minus
  when ':'
    :colon
  when '='
    :equal
  when '|'
    :pipe
  else
    :str
  end
end

.full_tokens(char_token_list) ⇒ Object 



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# File 'lib/command_search/lexer.rb', line 75

def full_tokens(char_token_list)
  out = char_token_list.clone

  out = group_quoted_strings(out)

  out = group_pattern(out, :pipe,    [:pipe,    :pipe])
  out = group_pattern(out, :compare, [:compare, :equal])

  out = group_pattern(out, :number,  [:number,  :period, :number])
  out = group_pattern(out, :number,  [:number,  :number])
  out = group_pattern(out, :number,  [:minus,   :number])

  out = group_pattern(out, :str,     [:equal])
  out = group_pattern(out, :str,     [:period])
  out = group_pattern(out, :str,     [:number,  :str])
  out = group_pattern(out, :str,     [:number,  :minus])
  out = group_pattern(out, :str,     [:str,     :number])
  out = group_pattern(out, :str,     [:str,     :minus])
  out = group_pattern(out, :str,     [:str,     :str])

  out = out.reject { |x| x[:type] == :space }
  out
end

.group_pattern(input, group_type, pattern) ⇒ Object 



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# File 'lib/command_search/lexer.rb', line 63

def group_pattern(input, group_type, pattern)
  out = input
  len = pattern.count
  while (out.map { |x| x[:type] }).each_cons(len).find_index(pattern)
    i = (out.map { |x| x[:type] }).each_cons(len).find_index(pattern)
    span = i..(i + len - 1)
    val = out[span].map { |x| x[:value] }.join()
    out[span] = { type: group_type, value: val }
  end
  out
end

.group_quoted_strings(input) ⇒ Object 



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# File 'lib/command_search/lexer.rb', line 46

def group_quoted_strings(input)
  out = input
  while value_indices("'", out).length >= 2 || value_indices('"', out).length >= 2
    (a, b) = value_indices("'", out).first(2)
    (c, d) = value_indices('"', out).first(2)
    if a && b && (c.nil? || (a < c))
      (x, y) = [a, b]
    else
      (x, y) = [c, d]
    end
    vals = out[x..y].map { |i| i[:value] }
    trimmed_vals = vals.take(vals.length - 1).drop(1)
    out[x..y] = { type: :quoted_str, value: trimmed_vals.join }
  end
  out
end

.lex(input) ⇒ Object 



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# File 'lib/command_search/lexer.rb', line 99

def lex(input)
  char_tokens = input.split('').map(&method(:char_token))
  full_tokens(char_tokens)
end

.value_indices(match, list) ⇒ Object 



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# File 'lib/command_search/lexer.rb', line 42

def value_indices(match, list)
  list.each_index.select { |i| list[i][:value] == match }
end