TreeNode * factor(void)
{ TreeNode * t = NULL;
switch (token) {
case NUM :
t = newExpNode(ConstK);
if ((t!=NULL) && (token==NUM))
t->attr.val = atoi(tokenString);
match(NUM);
break;
case ID :
t = newExpNode(IdK);
if ((t!=NULL) && (token==ID))
t->attr.name = copyString(tokenString);
match(ID);
break;
case LPAREN :
match(LPAREN);
t = expres();
match(RPAREN);
break;
default:
syntaxError("unexpected token -> ");
printToken(token,tokenString);
token = getToken();
break;
}
return t;
}
/* EBNF: factor -> "("expression")" | var | call | NUM */
static TreeNode * factor (void)
{ TreeNode * t;
TreeNode * p;
while (token == COMMENT) unexpectedTokenHandling();
switch (token) {
case LPAREN: /* "("expression")" */
match (LPAREN);
t = expression();
match (RPAREN);
break;
case ID: /* var | call */
t = newExpNode (IdK);
if ((t != NULL) && (token == ID))
t->attr.name = copyString (tokenString);
match (ID);
while (token == COMMENT) unexpectedTokenHandling();
/* call -> ID"("args")" */
if (token == LPAREN)
{ p = newExpNode (CallK);
p->attr.name = t->attr.name;
t = p;
match (LPAREN);
t->child[0] = args();
match (RPAREN);
}
/* var -> ID"["expression"]" */
else if (token == SLPAREN)
{ p = newExpNode (IdK);
p->attr.name = t->attr.name;
t = p;
match (SLPAREN);
t->child[0] = expression();
match (SRPAREN);
}
break;
case NUM: /* NUM */
t = newExpNode (ConstK);
if ((t != NULL) && (token == NUM))
t->attr.val = atoi(tokenString);
match (NUM);
break;
default:
unexpectedTokenHandling();
break;
}
return t;
}
/* var-declaration -> type-specifier ID ["["NUM"]"]";" */
static TreeNode * var_declaration (void)
{ TreeNode * t = NULL;
TreeNode * newNode = NULL;
while (token == COMMENT) unexpectedTokenHandling();
/* type-specifier */
switch (token) {
case VOID:
t = newStmtNode(VarDecK);
if (t != NULL) t->type = Void;
match (VOID);
break;
case INT:
t = newStmtNode(VarDecK);
if (t != NULL) t->type = Integer;
match (INT);
break;
default: unexpectedTokenHandling(); break;
}
while (token == COMMENT) unexpectedTokenHandling();
/* ID */
switch (token) {
case ID:
if (t != NULL)
t->attr.name = copyString(tokenString);
match (ID);
break;
default: unexpectedTokenHandling(); break;
}
while (token == COMMENT) unexpectedTokenHandling();
switch (token) {
/* var-declaration -> type-specifier ID";" */
case SEMI:
match (SEMI);
break;
/* var-declaration -> type-specifier ID "["NUM"]"";" */
case SLPAREN:
t->kind.stmt = ArrayDecK;
match (SLPAREN);
newNode = newExpNode (ConstK);
if ((t != NULL) && (newNode != NULL))
{ newNode->attr.val = atoi (tokenString);
t->child[0] = newNode;
}
match (NUM);
match (SRPAREN);
match (SEMI);
break;
default:
unexpectedTokenHandling();
break;
}
return t;
}
static exp_node *expression(void){
exp_node *expn = newExpNode();
if(match(TOKEN_LBRA, NO_CONSUME) ||
match(TOKEN_IDENTIFIER, NO_CONSUME) ||
match(TOKEN_LITERAL, NO_CONSUME))
if((expn->termn = term()) != NULL)
if((expn->termtln = term_tail()) != error)
return expn;
freeExp(expn);
return NULL;
}
TreeNode * term(void)
{ TreeNode * t = factor();
while ((token==TIMES)||(token==OVER))
{ TreeNode * p = newExpNode(OpK);
if (p!=NULL) {
p->child[0] = t;
p->attr.op = token;
t = p;
match(token);
p->child[1] = factor();
}
}
return t;
}
TreeNode * simple_exp(void)
{ TreeNode * t = term();
while ((token==PLUS)||(token==MINUS))
{ TreeNode * p = newExpNode(OpK);
if (p!=NULL) {
p->child[0] = t;
p->attr.op = token;
t = p;
match(token);
t->child[1] = term();
}
}
return t;
}
TreeNode * term(void) //term -> factor [mulop term]
{ TreeNode * t = factor();
while ((token==MUL)||(token==DIV))
{ TreeNode * p = newExpNode(OpK);
if (p!=NULL) {
p->child[0] = t;
p->attr.op = token;
t = p;
match(token);
p->child[1] = factor();
}
}
return t;
}
TreeNode * expres(void)
{ TreeNode * t = simple_exp();
if ((token==LT)||(token==EQ)) {
TreeNode * p = newExpNode(OpK);
if (p!=NULL) {
p->child[0] = t;
p->attr.op = token;
t = p;
}
match(token);
if (t!=NULL)
t->child[1] = simple_exp();
}
return t;
}
/* EBNF: term -> factor {mulop factor} */
static TreeNode * term (void)
{ TreeNode * t = factor();
TreeNode * newNode;
while (token == COMMENT) unexpectedTokenHandling();
/* {mulop factor} */
while (isMulop(token))
{ newNode = newExpNode (OpK);
if (newNode != NULL)
{ newNode->child[0] = t;
newNode->attr.op = token;
t = newNode;
}
match (token); // match mulop
if (t != NULL)
t->child[1] = factor();
}
return t;
}
/* EBNF: additive-expression -> term {addop term} */
static TreeNode * additive_expression (void)
{ TreeNode * t = term();
TreeNode * newNode;
while (token == COMMENT) unexpectedTokenHandling();
/* {addop term} */
while (isAddop(token))
{ newNode = newExpNode (OpK);
if (newNode != NULL)
{ newNode->child[0] = t;
newNode->attr.op = token;
t = newNode;
}
match (token); // match addop
if (t != NULL)
t->child[1] = term();
}
return t;
}
/* EBNF: simple-expression ->
* addtivite-expression [relop additivie-expression] */
static TreeNode * simple_expression (void)
{ TreeNode * t = additive_expression();
TreeNode * newNode;
while (token == COMMENT) unexpectedTokenHandling();
/* [relop additive-expression] */
if (isRelop(token))
{ newNode = newExpNode (OpK);
if (newNode != NULL)
{ newNode->child[0] = t;
newNode->attr.op = token;
t = newNode;
}
match (token); // match relop
if (t != NULL)
t->child[1] = additive_expression();
}
return t;
}
TreeNode* expression(void)
{
TreeNode* t = simple_exp();
if (s_token == LT || s_token == EQ )
{
TreeNode* p = newExpNode(OpK);
if (p != NULL)
{
p->child[0] = t;
p->attr.op = s_token;
t = p;
}
match(s_token); // TODO: This is equal to getToken(). why get a new token at here ?
if (t != NULL);
t->child[1] = simple_exp();
}
return t;
}
/* 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;
}
/* EBNF: declaration -> var-declaration | func-declaration
* both declaration types begin with 'type-specifier ID'
* type-specifier -> int | void */
static TreeNode * declaration(void)
{ TreeNode * t = NULL;
TreeNode * newNode = NULL;
char * name = NULL;
while (token == COMMENT) unexpectedTokenHandling();
/* type-specifier */
switch (token) {
case VOID:
t = newStmtNode (VarDecK);
if (t != NULL) t->type = Void;
match (VOID);
break;
case INT:
t = newStmtNode (VarDecK);
if (t != NULL) t->type = Integer;
match (INT);
break;
default: unexpectedTokenHandling(); break;
}
while (token == COMMENT) unexpectedTokenHandling();
/* ID */
switch (token) {
case ID:
if (t != NULL)
t->attr.name = copyString(tokenString);
match (ID);
break;
default: unexpectedTokenHandling(); break;
}
while (token == COMMENT) unexpectedTokenHandling();
switch (token) {
/* var-declaration -> type-specifier ID";" */
case SEMI:
match (SEMI);
break;
/* var-declaration -> type-specifier ID "["NUM"]"";" */
case SLPAREN:
if (t != NULL)
t->kind.stmt = ArrayDecK;
match (SLPAREN);
if (token != NUM)
unexpectedTokenHandling();
else
{ newNode = newExpNode (ConstK);
if ((newNode != NULL) && (t != NULL))
{ newNode->attr.val = atoi(tokenString);
t->child[0] = newNode;
match (NUM);
}
}
match (SRPAREN);
match (SEMI);
/* func-declaration ->
* type-specifier ID "("params")" compound-stmt */
case LPAREN:
if (t != NULL)
{ t->kind.stmt = FuncDecK;
match (LPAREN);
t->child[0] = params();
match (RPAREN);
t->child[1] = compound_stmt();
}
break;
default: unexpectedTokenHandling(); break;
}
return t;
}
