void HandleForEachStatement(ForEachStatement tree)
{
EnterBlock();
var f = GetCurrentFunction();
Instruction code;
// get table iter
HandleExpRead(tree.exp);
var table_register = GenerateRegisterId();
var iter_register = table_register;
code = Instruction.AB(OpType.OpType_TableIter, iter_register, table_register);
f.AddInstruction(code, tree.k.m_line);
EnterLoop();
{
EnterBlock();
var k_register = GenerateRegisterId();
if (tree.k != null)
{
InsertName(tree.k.m_string, k_register);
}
var v_register = GenerateRegisterId();
InsertName(tree.v.m_string, v_register);
code = Instruction.ABC(OpType.OpType_TableIterNext, iter_register, k_register, v_register);
f.AddInstruction(code, tree.k.m_line);
// jump to loop tail when the first name value is nil
code = Instruction.ABx(OpType.OpType_JmpNil, k_register, 0);
int index = f.AddInstruction(code, tree.k.m_line);
AddLoopJumpInfo(JumpType.JumpTail, index);
HandleBlock(tree.block);
LeaveBlock();
// jump to loop head
code = Instruction.Bx(OpType.OpType_Jmp, 0);
index = f.AddInstruction(code, -1);
AddLoopJumpInfo(JumpType.JumpHead, index);
}
LeaveLoop();
LeaveBlock();
}
ForEachStatement ParseForEachStatement()
{
NextToken();// skip 'foreach'
var statement = new ForEachStatement(_current.m_line);
if (NextToken().m_type != (int)TokenType.NAME)
{
throw NewParserException("expect 'id' in foreach-statement", _current);
}
if (LookAhead().m_type == (int)',')
{
statement.k = _current;
NextToken();
if (NextToken().m_type != (int)TokenType.NAME)
{
throw NewParserException("expect 'id' in foreach-statement after ','", _current);
}
statement.v = _current;
}
else
{
statement.v = _current;
}
if (NextToken().m_type != (int)TokenType.IN)
{
throw NewParserException("expect 'in' in foreach-statement", _current);
}
statement.exp = ParseExp();
if (NextToken().m_type != (int)TokenType.DO)
{
throw NewParserException("expect 'do' to start foreach-body", _current);
}
statement.block = ParseBlock();
if (NextToken().m_type != (int)TokenType.END)
{
throw NewParserException("expect 'end' to complete foreach-body", _current);
}
return(statement);
}