parser/operator.cpp

   1 #include <ail/file.hpp>
   2 #include <ail/string.hpp>
   3 #include <fridh/parser.hpp>
   4 #include <fridh/lexer.hpp>
   5
   6 namespace fridh
   7 {
   8         void call_check(std::size_t extremum_offset)
   9         {
  10                 if(extremum_offset != 1)
  11                         throw ail::exception("Invalid call offset encountered during operator resolution");
  12         }
  13
  14         void parser::operator_resolution(parse_tree_nodes & input, parse_tree_node & output)
  15         {
  16                 if(input.size() != 1)
  17                 {
  18                         output = input[0];
  19                         return;
  20                 }
  21
  22                 bool got_an_operator = false;
  23                 word extremum;
  24                 std::size_t extremum_offset;
  25
  26                 for(std::size_t i = 0, end = input.size(); i < end; i++)
  27                 {
  28                         word precedence;
  29                         parse_tree_node & current_node = input[i];
  30                         if(get_parse_tree_node_precedence(current_node, precedence))
  31                         {
  32                                 if
  33                                 (
  34                                         !got_an_operator ||
  35                                         precedence > extremum ||
  36                                         (is_right_to_left_operator(current_node) && precedence == extremum)
  37                                 )
  38                                 {
  39                                         got_an_operator = true;
  40                                         extremum = precedence;
  41                                         extremum_offset = i;
  42                                 }
  43                         }
  44                 }
  45
  46                 if(!got_an_operator)
  47                         error("Failed to perform operator resolution");
  48
  49                 parse_tree_node & operator_node = input[extremum_offset];
  50                 std::size_t next_offset = extremum_offset + 1;
  51                 switch(operator_node.type)
  52                 {
  53                         case parse_tree_node_type::unary_operator_node:
  54                         {
  55                                 std::size_t argument_offset = next_offset;
  56                                 parse_tree_unary_operator_node & unary_operator_node = *operator_node.unary_operator_pointer;
  57                                 unary_operator_node.argument = input.at(argument_offset);
  58                                 input.erase(input.begin() + argument_offset);
  59                                 break;
  60                         }
  61
  62                         case parse_tree_node_type::binary_operator_node:
  63                         {
  64                                 parse_tree_binary_operator_node & binary_operator_node = *operator_node.binary_operator_pointer;
  65
  66                                 parse_tree_nodes
  67                                         left_side,
  68                                         right_side;
  69
  70                                 std::copy(input.begin(), input.begin() + extremum_offset, left_side.begin());
  71                                 std::copy(input.begin() + next_offset, input.end(), right_side.begin());
  72
  73                                 operator_resolution(left_side, binary_operator_node.left_argument);
  74                                 operator_resolution(right_side, binary_operator_node.right_argument);
  75
  76                                 output = operator_node;
  77                                 break;
  78                         }
  79
  80                         case parse_tree_node_type::call:
  81                                 //this is questionable
  82                                 call_check(extremum_offset);
  83                                 operator_node.call_pointer->function = input[0];
  84                                 input.erase(input.begin());
  85                                 break;
  86
  87                         case parse_tree_node_type::call_operator:
  88                         case parse_tree_node_type::spaced_call_operator:
  89                                 call_check(extremum_offset);
  90                                 operator_node.is_call();
  91                                 operator_node.call_pointer->function = input[0];
  92                                 input.erase(input.begin());
  93                                 if(operator_node.type != parse_tree_node_type::spaced_call_operator && next_offset != input.size())
  94                                 {
  95                                         //it's an unary call
  96                                         operator_node.call_pointer->arguments.push_back(input[next_offset]);
  97                                         input.erase(input.end() - 1);
  98                                 }
  99                                 break;
 100
 101                         default:
 102                                 throw ail::exception("Invalid operator node type encountered during operator resolution");
 103                 }
 104         }
 105 }