Re-implemented ?: parsing in value expressions. "a ? b : c" is implemented by

translating it into the equivalent syntax tree "(a & b) | c", since this
expression evaluates to the value of b if a is true, otherwise c.

parser.cc

@@ -134,7 +134,7 @@ expr_t::parser_t::parse_value_term(std::istream& in,
 
       tok = next_token(in, tflags);
       if (tok.kind != token_t::RPAREN)
-	tok.unexpected(0xff, ')');
+	tok.expected(')');
 
       node = call_node;
     } else {
@@ -158,7 +158,7 @@ expr_t::parser_t::parse_value_term(std::istream& in,
 
     tok = next_token(in, tflags);
     if (tok.kind != token_t::RPAREN)
-      tok.unexpected(0xff, ')');
+      tok.expected(')');
     break;
 
   default:
@@ -382,11 +382,47 @@ expr_t::parser_t::parse_or_expr(std::istream& in,
   return node;
 }
 
+expr_t::ptr_op_t
+expr_t::parser_t::parse_querycolon_expr(std::istream& in,
+					const flags_t tflags) const
+{
+  ptr_op_t node(parse_or_expr(in, tflags));
+
+  if (node) {
+    token_t& tok = next_token(in, tflags);
+
+    if (tok.kind == token_t::QUERY) {
+      ptr_op_t prev(node);
+      node = new op_t(op_t::O_AND);
+      node->set_left(prev);
+      node->set_right(parse_or_expr(in, tflags));
+      if (! node->right())
+	throw_(parse_error,
+	       tok.symbol << " operator not followed by argument");
+
+      token_t& next_tok = next_token(in, tflags);
+      if (next_tok.kind != token_t::COLON)
+	next_tok.expected(':');
+
+      prev = node;
+      node = new op_t(op_t::O_OR);
+      node->set_left(prev);
+      node->set_right(parse_or_expr(in, tflags));
+      if (! node->right())
+	throw_(parse_error,
+	       tok.symbol << " operator not followed by argument");
+    } else {
+      push_token(tok);
+    }
+  }
+  return node;
+}
+
 expr_t::ptr_op_t
 expr_t::parser_t::parse_value_expr(std::istream& in,
 				   const flags_t tflags) const
 {
-  ptr_op_t node(parse_or_expr(in, tflags));
+  ptr_op_t node(parse_querycolon_expr(in, tflags));
 
   if (node) {
     token_t& tok = next_token(in, tflags);

token.cc

@@ -164,7 +164,7 @@ void expr_t::token_t::next(std::istream& in, const unsigned int pflags)
     char buf[256];
     READ_INTO_(in, buf, 255, c, length, c != ']');
     if (c != ']')
-      unexpected(c, ']');
+      expected(']', c);
 
     in.get(c);
     length++;
@@ -182,7 +182,7 @@ void expr_t::token_t::next(std::istream& in, const unsigned int pflags)
     char buf[4096];
     READ_INTO_(in, buf, 4095, c, length, c != delim);
     if (c != delim)
-      unexpected(c, delim);
+      expected(delim, c);
     in.get(c);
     length++;
     kind = VALUE;
@@ -196,7 +196,7 @@ void expr_t::token_t::next(std::istream& in, const unsigned int pflags)
     temp.parse(in, AMOUNT_PARSE_NO_MIGRATE);
     in.get(c);
     if (c != '}')
-      unexpected(c, '}');
+      expected('}', c);
     length++;
     kind  = VALUE;
     value = temp;
@@ -231,6 +231,16 @@ void expr_t::token_t::next(std::istream& in, const unsigned int pflags)
     kind = STAR;
     break;
 
+  case '?':
+    in.get(c);
+    kind = QUERY;
+    break;
+
+  case ':':
+    in.get(c);
+    kind = COLON;
+    break;
+
   case 'c':
   case 'C':
   case 'p':
@@ -266,7 +276,7 @@ void expr_t::token_t::next(std::istream& in, const unsigned int pflags)
     char buf[256];
     READ_INTO_(in, buf, 255, c, length, c != '/');
     if (c != '/')
-      unexpected(c, '/');
+      expected('/', c);
     in.get(c);
     length++;
 
@@ -379,9 +389,9 @@ void expr_t::token_t::unexpected()
   }
 }
 
-void expr_t::token_t::unexpected(char c, char wanted)
+void expr_t::token_t::expected(char wanted, char c)
 {
-  if (static_cast<unsigned char>(c) == 0xff) {
+  if (c == '\0') {
     if (wanted)
       throw_(parse_error, "Missing '" << wanted << "'");
     else

token.h

@@ -71,6 +71,9 @@ struct expr_t::token_t : public noncopyable, public supports_flags<>
     KW_OR,			// |
     KW_MOD,			// %
 
+    QUERY,			// ?
+    COLON,			// :
+
     COMMA,			// ,
 
     TOK_EOF,
@@ -111,7 +114,7 @@ struct expr_t::token_t : public noncopyable, public supports_flags<>
   void rewind(std::istream& in);
   void unexpected();
 
-  static void unexpected(char c, char wanted = '\0');
+  static void expected(char wanted, char c = '\0');
 };
 
 } // namespace ledger