Class: SportDb::Tokens

Inherits:
Object
  • Object
show all
Defined in:
lib/sportdb/parser/lexer_buffer.rb

Overview

token iter/find better name

e.g. TokenBuffer/Scanner or such ??

Instance Method Summary collapse

Constructor Details

#initialize(tokens) ⇒ Tokens

Returns a new instance of Tokens.



19
20
21
22
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 19

def initialize( tokens )
    @tokens = tokens
    @pos    = 0
end

Instance Method Details

#cur ⇒ Object 



46
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 46

def cur()           peek(0); end

#eos? ⇒ Boolean

Returns:

  • (Boolean) 


25
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 25

def eos?() @pos >= @tokens.size; end

#match?(*pattern) ⇒ Boolean

pattern e.g. [:TEXT, [:VS,:SCORE], :TEXT]

Returns:

  • (Boolean) 


31
32
33
34
35
36
37
38
39
40
41
42
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 31

def match?( *pattern )
    ## puts "  starting match? #{pattern.inspect} @ #{@pos}"
    pattern.each_with_index do |types,offset|
        tok = peek(offset)
        return false if tok.nil?   ## no more tokens (cannot match)

        ## if single symbol wrap in array
        types = types.is_a?(Array) ? types : [types]
        return false  unless types.include?( tok.type )
    end
    true
end

#next ⇒ Object 



57
58
59
60
61
62
63
64
65
66
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 57

def next
   # if @pos >= @tokens.size
   #     raise ArgumentError, "end of array - #{@pos} >= #{@tokens.size}"
   # end
   #   throw (standard) end of iteration here why? why not?

    t = @tokens[@pos]
    @pos += 1
    t
end

#peek(offset = 1) ⇒ Object 



48
49
50
51
52
53
54
55
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 48

def peek(offset=1)
    ## return nil if eos
    if @pos+offset >= @tokens.size
        nil
    else
       @tokens[@pos+offset]
    end
end

#pos ⇒ Object 



24
 
# File 'lib/sportdb/parser/lexer_buffer.rb', line 24

def pos()  @pos; end