get_production(short conflict_number,
DslToken tokens)
{
short entry = 0;
int index, level;
if (conflict_number <= TOTAL_CONFLICTS)
{
entry = (short)(conflict_number + (START_CONFLICT - 1));
level = 1;
while (entry >= START_CONFLICT)
{
index = Conflict_row [entry - (START_CONFLICT - 1)];
index += tokens.peek(level);
entry = Conflict [index];
++level;
}
}
return(entry);
}
parse(ref DslAction action,
ref DslToken tokens,
ref DslError error,
short start_symbol)
{
short rhs, lhs;
short production_number, entry, symbol, token, new_token;
int production_length, top, index, level;
short *stack = stackalloc short[65535];
top = 65534;
stack[top] = 0;
if (start_symbol == 0)
{
start_symbol = START_SYMBOL;
}
if (top > 0)
{
stack[--top] = start_symbol;
}
else
{
error.message("DslParse: stack overflow\n", ref tokens); return;
}
token = tokens.get();
new_token = token;
for (symbol = (stack[top] != 0 ? stack[top++] : (short)0); symbol != 0;)
{
if (symbol >= START_ACTION)
{
action.execute(symbol - (START_ACTION - 1));
}
else if (symbol >= START_SYMBOL)
{
entry = 0;
level = 1;
production_number = get_conditional_production(symbol);
if (production_number != 0)
{
entry = get_predicted_entry(tokens,
production_number, token,
level, 1);
}
if (entry == 0)
{
index = Parse_row[symbol - (START_SYMBOL - 1)];
index += token;
entry = Parse[index];
}
while (entry >= START_CONFLICT)
{
index = Conflict_row[entry - (START_CONFLICT - 1)];
index += tokens.peek(level);
entry = Conflict[index];
++level;
}
if (entry != 0)
{
index = Production_row[entry];
production_length = Production[index] - 1;
lhs = Production[++index];
if (lhs == symbol)
{
action.predict(entry);
index += production_length;
for (; production_length-- > 0; --index)
{
if (top > 0)
{
stack[--top] = Production[index];
}
else
{
error.message("DslParse: stack overflow\n", ref tokens); return;
}
}
}
else
{
new_token = error.no_entry(symbol, token, level - 1, ref tokens);
}
}
else // no table entry
{
new_token = error.no_entry(symbol, token, level - 1, ref tokens);
}
}
else if (symbol > 0)
{
if (symbol == token)
{
token = tokens.get();
new_token = token;
}
else
{
new_token = error.mismatch(symbol, token, ref tokens);
}
}
else
{
error.message("\n parser error: symbol value 0\n", ref tokens);
}
if (token != new_token)
{
if (new_token != 0)
{
token = new_token;
}
if (token != END_OF_SLK_INPUT_)
{
continue;
}
}
symbol = (stack[top] != 0 ? stack[top++] : (short)0);
}
if (token != END_OF_SLK_INPUT_)
{
error.input_left(ref tokens);
}
}