# File racc/parser.rb, line 281 def _racc_do_parse_rb(arg, in_debug) action_table, action_check, action_default, action_pointer, _, _, _, _, _, _, token_table, * = arg _racc_init_sysvars tok = act = i = nil catch(:racc_end_parse) { while true if i = action_pointer[@racc_state[-1]] if @racc_read_next if @racc_t != 0 # not EOF tok, @racc_val = next_token() unless tok # EOF @racc_t = 0 else @racc_t = (token_table[tok] or 1) # error token end racc_read_token(@racc_t, tok, @racc_val) if @yydebug @racc_read_next = false end end i += @racc_t unless i >= 0 and act = action_table[i] and action_check[i] == @racc_state[-1] act = action_default[@racc_state[-1]] end else act = action_default[@racc_state[-1]] end while act = _racc_evalact(act, arg) ; end end } end
# File racc/parser.rb, line 481 def _racc_do_reduce(arg, act) _, _, _, _, goto_table, goto_check, goto_default, goto_pointer, nt_base, reduce_table, _, _, _, use_result, * = arg state = @racc_state vstack = @racc_vstack tstack = @racc_tstack i = act * -3 len = reduce_table[i] reduce_to = reduce_table[i+1] method_id = reduce_table[i+2] void_array = [] tmp_t = tstack[-len, len] if @yydebug tmp_v = vstack[-len, len] tstack[-len, len] = void_array if @yydebug vstack[-len, len] = void_array state[-len, len] = void_array # tstack must be updated AFTER method call if use_result vstack.push __send__(method_id, tmp_v, vstack, tmp_v[0]) else vstack.push __send__(method_id, tmp_v, vstack) end tstack.push reduce_to racc_reduce(tmp_t, reduce_to, tstack, vstack) if @yydebug k1 = reduce_to - nt_base if i = goto_pointer[k1] i += state[-1] if i >= 0 and (curstate = goto_table[i]) and goto_check[i] == k1 return curstate end end goto_default[k1] end
common
# File racc/parser.rb, line 384 def _racc_evalact(act, arg) action_table, action_check, _, action_pointer, _, _, _, _, _, _, _, shift_n, reduce_n, * = arg nerr = 0 # tmp if act > 0 and act < shift_n # # shift # if @racc_error_status > 0 @racc_error_status -= 1 unless @racc_t <= 1 # error token or EOF end @racc_vstack.push @racc_val @racc_state.push act @racc_read_next = true if @yydebug @racc_tstack.push @racc_t racc_shift @racc_t, @racc_tstack, @racc_vstack end elsif act < 0 and act > -reduce_n # # reduce # code = catch(:racc_jump) { @racc_state.push _racc_do_reduce(arg, act) false } if code case code when 1 # yyerror @racc_user_yyerror = true # user_yyerror return -reduce_n when 2 # yyaccept return shift_n else raise '[Racc Bug] unknown jump code' end end elsif act == shift_n # # accept # racc_accept if @yydebug throw :racc_end_parse, @racc_vstack[0] elsif act == -reduce_n # # error # case @racc_error_status when 0 unless arg[21] # user_yyerror nerr += 1 on_error @racc_t, @racc_val, @racc_vstack end when 3 if @racc_t == 0 # is $ # We're at EOF, and another error occurred immediately after # attempting auto-recovery throw :racc_end_parse, nil end @racc_read_next = true end @racc_user_yyerror = false @racc_error_status = 3 while true if i = action_pointer[@racc_state[-1]] i += 1 # error token if i >= 0 and (act = action_table[i]) and action_check[i] == @racc_state[-1] break end end throw :racc_end_parse, nil if @racc_state.size <= 1 @racc_state.pop @racc_vstack.pop if @yydebug @racc_tstack.pop racc_e_pop @racc_state, @racc_tstack, @racc_vstack end end return act else raise "[Racc Bug] unknown action #{act.inspect}" end racc_next_state(@racc_state[-1], @racc_state) if @yydebug nil end
# File racc/parser.rb, line 234 def _racc_init_sysvars @racc_state = [0] @racc_tstack = [] @racc_vstack = [] @racc_t = nil @racc_val = nil @racc_read_next = true @racc_user_yyerror = false @racc_error_status = 0 end
# File racc/parser.rb, line 222 def _racc_setup @yydebug = false unless self.class::Racc_debug_parser @yydebug = false unless defined?(@yydebug) if @yydebug @racc_debug_out = $stderr unless defined?(@racc_debug_out) @racc_debug_out ||= $stderr end arg = self.class::Racc_arg arg[13] = true if arg.size < 14 arg end
# File racc/parser.rb, line 331 def _racc_yyparse_rb(recv, mid, arg, c_debug) action_table, action_check, action_default, action_pointer, _, _, _, _, _, _, token_table, * = arg _racc_init_sysvars catch(:racc_end_parse) { until i = action_pointer[@racc_state[-1]] while act = _racc_evalact(action_default[@racc_state[-1]], arg) ; end end recv.__send__(mid) do |tok, val| unless tok @racc_t = 0 else @racc_t = (token_table[tok] or 1) # error token end @racc_val = val @racc_read_next = false i += @racc_t unless i >= 0 and act = action_table[i] and action_check[i] == @racc_state[-1] act = action_default[@racc_state[-1]] end while act = _racc_evalact(act, arg) ; end while !(i = action_pointer[@racc_state[-1]]) || ! @racc_read_next || @racc_t == 0 # $ unless i and i += @racc_t and i >= 0 and act = action_table[i] and action_check[i] == @racc_state[-1] act = action_default[@racc_state[-1]] end while act = _racc_evalact(act, arg) ; end end end } end
The method to fetch next token. If you use do_parse method, you must implement next_token.
The format of return value is [TOKEN_SYMBOL, VALUE].
token-symbol
is represented by Ruby’s symbol by default, e.g.
:IDENT for ‘IDENT’. “;” (String) for ‘;’.
The final symbol (End of file) must be false.
# File racc/parser.rb, line 277 def next_token raise NotImplementedError, "#{self.class}\#next_token is not defined" end
This method is called when a parse error is found.
ERROR_TOKEN_ID is an internal ID of token which caused error. You can get string representation of this ID by calling token_to_str.
ERROR_VALUE is a value of error token.
value_stack is a stack of symbol values. DO NOT MODIFY this object.
This method raises ParseError by default.
If this method returns, parsers enter “error recovering mode”.
# File racc/parser.rb, line 537 def on_error(t, val, vstack) raise ParseError, sprintf("\nparse error on value %s (%s)", val.inspect, token_to_str(t) || '?') end
# File racc/parser.rb, line 586 def racc_accept @racc_debug_out.puts 'accept' @racc_debug_out.puts end
# File racc/parser.rb, line 591 def racc_e_pop(state, tstack, vstack) @racc_debug_out.puts 'error recovering mode: pop token' racc_print_states state racc_print_stacks tstack, vstack @racc_debug_out.puts end
# File racc/parser.rb, line 598 def racc_next_state(curstate, state) @racc_debug_out.puts "goto #{curstate}" racc_print_states state @racc_debug_out.puts end
# File racc/parser.rb, line 604 def racc_print_stacks(t, v) out = @racc_debug_out out.print ' [' t.each_index do |i| out.print ' (', racc_token2str(t[i]), ' ', v[i].inspect, ')' end out.puts ' ]' end
# File racc/parser.rb, line 613 def racc_print_states(s) out = @racc_debug_out out.print ' [' s.each {|st| out.print ' ', st } out.puts ' ]' end
For debugging output
# File racc/parser.rb, line 560 def racc_read_token(t, tok, val) @racc_debug_out.print 'read ' @racc_debug_out.print tok.inspect, '(', racc_token2str(t), ') ' @racc_debug_out.puts val.inspect @racc_debug_out.puts end
# File racc/parser.rb, line 573 def racc_reduce(toks, sim, tstack, vstack) out = @racc_debug_out out.print 'reduce ' if toks.empty? out.print ' <none>' else toks.each {|t| out.print ' ', racc_token2str(t) } end out.puts " --> #{racc_token2str(sim)}" racc_print_stacks tstack, vstack @racc_debug_out.puts end
# File racc/parser.rb, line 567 def racc_shift(tok, tstack, vstack) @racc_debug_out.puts "shift #{racc_token2str tok}" racc_print_stacks tstack, vstack @racc_debug_out.puts end
# File racc/parser.rb, line 620 def racc_token2str(tok) self.class::Racc_token_to_s_table[tok] or raise "[Racc Bug] can't convert token #{tok} to string" end
Convert internal ID of token symbol to the string.
# File racc/parser.rb, line 626 def token_to_str(t) self.class::Racc_token_to_s_table[t] end
Exit parser. Return value is Symbol_Value_Stack.
# File racc/parser.rb, line 550 def yyaccept throw :racc_jump, 2 end
Leave error recovering mode.
# File racc/parser.rb, line 555 def yyerrok @racc_error_status = 0 end
Enter error recovering mode. This method does not call on_error.
# File racc/parser.rb, line 544 def yyerror throw :racc_jump, 1 end