public static void parse( int display,
SlkAction action,
SlkToken tokens,
SlkError error,
SlkLog log,
short start_symbol )
{
short rhs, lhs;
short production_number, entry, symbol, token, new_token;
int top, index, level;
short[] stack = new short[512];
top = 511;
stack [ top ] = 0;
if ( start_symbol == 0 ) {
start_symbol = START_SYMBOL;
}
if ( top > 0 ) { stack [--top] = start_symbol;
} else { log.trace ("SlkParse: stack overflow\n"); return; }
token = tokens.get();
new_token = token;
if ( display != 0 ) {
log.trace ( "\n\n\t\tPARSE DERIVATION\n\n" );
}
for ( symbol = (stack[top] != 0 ? stack[top++] : (short) 0); symbol != 0; ) {
if ( symbol >= START_SYMBOL ) { // nonterminal symbol
entry = 0;
level = 1;
production_number = get_conditional_production ( symbol );
if ( production_number != 0 ) {
entry = get_predicted_entry ( display, tokens, log,
production_number, token,
level, 1 );
}
if ( entry == 0 ) {
index = Parse_row [ symbol - (START_SYMBOL-1) ];
index += Terminal_to_index [ token ];
entry = Parse [ index ];
}
while ( entry < 0 ) {
index = Conflict_row [-entry];
index += Terminal_to_index [tokens.peek (level)];
entry = Conflict [ index ];
++level;
}
if ( entry != 0 ) {
index = Production_row [ entry ];
lhs = Production [ ++index ];
if ( lhs == symbol ) { // valid row for lhs
rhs = Production [++index];
for ( ; rhs != 0; rhs = Production [++index] ) {
if ( top > 0 ) { stack [--top] = rhs;
} else { log.trace ("SlkParse: stack overflow\n"); return; }
}
if ( display != 0 ) {
log.trace_production ( entry );
}
} else { // lhs does not match
new_token = error.no_entry ( symbol, token, level-1 );
}
} else { // no table entry
new_token = error.no_entry ( symbol, token, level-1 );
}
} else if ( symbol > 0 ) { // terminal symbol
if ( symbol == token ) {
token = tokens.get();
new_token = token;
} else { // token mismatch
new_token = error.mismatch ( symbol, token );
}
} else { // action symbol
if ( display != 0 ) {
log.trace_action ( symbol );
}
action.execute ( -symbol );
}
if ( token != new_token ) {
if ( new_token != 0 ) {
token = new_token;
}
if ( token != END_OF_SLK_INPUT_ ) {
continue; // try this token
}
}
symbol = (stack[top] != 0 ? stack[top++] : (short) 0);
}
if ( token != END_OF_SLK_INPUT_ ) { // input left over
error.input_left ();
}
}
private static short get_predicted_entry( int display,
SlkToken tokens,
SlkLog log,
short production_number,
short token,
int scan_level,
int depth )
{
return 0;
}