PostgreSQL array parser that handles all types of input.
This parser is very simple and unoptimized, but should still be O(n) where n is the length of the input string.
Current position in the input string.
Public Class methods
Set the source for the input, and any converter callable to call with objects to be created. For nested parsers the source may contain text after the end current parse, which will be ignored.
# File lib/sequel/extensions/pg_array.rb, line 362 def initialize(source, converter=nil) @source = source @source_length = source.length @converter = converter @pos = -1 @entries =  @recorded = "" @dimension = 0 end
Public Instance methods
Take the buffer of recorded characters and add it to the array of entries, and use a new buffer for recorded characters.
# File lib/sequel/extensions/pg_array.rb, line 391 def new_entry(include_empty=false) if !@recorded.empty? || include_empty entry = @recorded if entry == NULL && !include_empty entry = nil elsif @converter entry = @converter.call(entry) end @entries.push(entry) @recorded = "" end end
Return 2 objects, whether the next character in the input was escaped with a backslash, and what the next character is.
# File lib/sequel/extensions/pg_array.rb, line 374 def next_char @pos += 1 if (c = @source[@pos..@pos]) == BACKSLASH @pos += 1 [true, @source[@pos..@pos]] else [false, c] end end
Parse the input character by character, returning an array of parsed (and potentially converted) objects.
# File lib/sequel/extensions/pg_array.rb, line 406 def parse(nested=false) # quote sets whether we are inside of a quoted string. quote = false until @pos >= @source_length escaped, char = next_char if char == OPEN_BRACE && !quote @dimension += 1 if (@dimension > 1) # Multi-dimensional array encounter, use a subparser # to parse the next level down. subparser = self.class.new(@source[@pos..-1], @converter) @entries.push(subparser.parse(true)) @pos += subparser.pos - 1 end elsif char == CLOSE_BRACE && !quote @dimension -= 1 if (@dimension == 0) new_entry # Exit early if inside a subparser, since the # text after parsing the current level should be # ignored as it is handled by the parent parser. return @entries if nested end elsif char == QUOTE && !escaped # If already inside the quoted string, this is the # ending quote, so add the entry. Otherwise, this # is the opening quote, so set the quote flag. new_entry(true) if quote quote = !quote elsif char == COMMA && !quote # If not inside a string and a comma occurs, it indicates # the end of the entry, so add the entry. new_entry else # Add the character to the recorded character buffer. record(char) end end raise Sequel::Error, "array dimensions not balanced" unless @dimension == 0 @entries end
Add a new character to the buffer of recorded characters.
# File lib/sequel/extensions/pg_array.rb, line 385 def record(c) @recorded << c end