double Formulaeditor::expression(int& nPosition, QString& strCharacter)
{
QString strOperator;
double erg = simple_expression(nPosition, strCharacter);
while (strCharacter == "+" || strCharacter == "-")
{
strOperator = strCharacter;
char_n(nPosition, strCharacter);
if (strOperator == "+")
erg += simple_expression(nPosition, strCharacter);
else if (strOperator == "-")
erg -= simple_expression(nPosition, strCharacter);
}
return erg;
}
std::list<SimpleExpression> Parser::simple_expression_list(){
std::list<SimpleExpression> se;
if (lexer->getToken() == TOK_AND){
match(TOK_AND, "expression_list_aux");
se.push_back(simple_expression());
std::list<SimpleExpression> exprlist (simple_expression_list());
/* copy exprlist into se as merge requires operator< or something */
for (std::list<SimpleExpression>::iterator i = exprlist.begin();
i != exprlist.end();
++i)
se.push_back(*i);
}
return se;
}
/* expression -> var "=" expression | simple-expression
* var -> ID ["["expression"]"]*/
static TreeNode * expression (void)
{ TreeNode * t = newExpNode(IdK);
TreeNode * p = NULL;
TreeNode * newNode = NULL;
#define CALL 1
#define ARRAY 2
int factorType = 0;
while (token == COMMENT) unexpectedTokenHandling();
if (token == ID)
{
if (t != NULL)
t->attr.name = copyString(tokenString);
match (ID);
/* var -> ID "["expression"]" */
if (token == SLPAREN)
{ factorType = ARRAY;
match (SLPAREN);
t->child[0] = expression();
match (SRPAREN);
/* ID "["expression"]" "=" expression */
if (token == ASSIGN)
{ match (ASSIGN);
newNode = newStmtNode(AssignK);
if (t != NULL)
{ newNode->child[0] = t;
t= newNode;
t->child[1] = expression();
if (token != SEMI)
unexpectedTokenHandling();
}
}
}
/* simple-expression => call => ID "("args")" */
else if (token == LPAREN)
{ factorType = CALL;
match (LPAREN);
if (t != NULL)
{ t->nodekind = ExpK;
t->kind.exp = CallK;
t->child[0] = args();
}
match (RPAREN);
}
/* var | call is followed by assignment, operation,
* semi-colon or comma. */
while (token == COMMENT) unexpectedTokenHandling();
if (token == ASSIGN)
{ if ((factorType == CALL) || (factorType == ARRAY))
unexpectedTokenHandling();
/* ID "=" expression */
else
{ match (ASSIGN);
newNode = newStmtNode(AssignK);
if (t != NULL)
{ newNode->child[0] = t;
t= newNode;
t->child[1] = expression();
if (token != SEMI)
unexpectedTokenHandling();
}
}
}
/* ID [("("args")"|"["expression"]")]
* op additivie-expression */
else if (isOp (token))
{ newNode = newExpNode (OpK);
if (newNode != NULL)
{ newNode->child[0] = t;
newNode->attr.op = token;
t = newNode;
}
match (token);
if (t != NULL)
t->child[1] = additive_expression();
}
else if ((token != SEMI) && (token != COMMA) && (token != RPAREN))
unexpectedTokenHandling();
}
else if ((token == LPAREN) || (token == NUM))
t = simple_expression();
else
unexpectedTokenHandling();
return t;
}
Expression* Parser::expression(){
Expression* e = new Expression();
e->addSimpleExpression( simple_expression() );
e->addSimpleExpression( simple_expression_list());
return e;
}
