void if_stat(){
match(IF);
expr();
match(THEN);
stat_list();
if (lookahead == ELSE){
match(ELSE);
stat_list();
}
match(END);
}
/*Controlla la semantica del nodo while e ne restituisce il codice*/
Code while_stat(Pnode while_stat_node){
//Imposto le due parti del nodo
Pnode expr_node = while_stat_node->child;
Pnode stat_list_node = while_stat_node->child->brother;
//Definisco la variabile che contiene il codice da ritornare
Code while_stat_code;
//La generazione dell'ambiente viene fatta all'interno della funzione stat_list
//Genero il codice di expr
Pschema schema_expr = (Pschema) newmem(sizeof(Schema));
Code expr_code = expr(expr_node,schema_expr);
//Controllo i vincoli semantici
if (schema_expr->type!=BOOLEAN)
semerror(expr_node,"Expected boolean type");
//Genero il codice di stat_list
Code stat_list_code = stat_list(stat_list_node);
//Calcolo gli offset
int exit = stat_list_code.size + 2;
int up = -(expr_code.size + stat_list_code.size + 1);
//Genero il codice di while_stat
while_stat_code = concode(expr_code,makecode1(T_SKIPF,exit),stat_list_code,makecode1(T_SKIP,up),endcode());
return while_stat_code;
}
void while_stat(){
match(WHILE);
expr();
match(DO);
stat_list();
match(END);
}
/*Controlla la semantica del nodo if e ne ritorna il codice*/
Code if_stat(Pnode if_stat_node){
#ifdef DEBUG_IF_STAT
printf("IF_STAT - enter\n");
#endif
//Imposto le tre parti del nodo
Pnode expr_node = if_stat_node->child;
Pnode then_node = if_stat_node->child->brother;
Pnode else_node = if_stat_node->child->brother->brother;
//Definisco la variabile che contiene il codice da ritornare
Code if_stat_code ;
//La generazione dell'ambiente viene fatta all'interno della funzione stat_list
//Genero il codice di expr
Pschema schema_expr = (Pschema) newmem(sizeof(Schema));
Code expr_code = expr(expr_node,schema_expr);
//Controllo i vincoli semantici
if (schema_expr->type!=BOOLEAN)
semerror(expr_node,"Expected boolean type");
//Genero il codice di then_node
Code then_code = stat_list(then_node);
if (else_node==NULL){//if then endif
//Calcolo l'offset
int offset = then_code.size + 1;
//Genero il codice di if_stat
if_stat_code = concode(expr_code,makecode1(T_SKIPF,offset),then_code,endcode());
}
else {//if then else
//Genero il codice di else_node
Code else_code = stat_list(else_node);
//Calcolo gli offset
int offset_then = then_code.size + 2;
int offset_else = else_code.size + 1;
//Genero il codice di if_stat
if_stat_code = concode(expr_code,makecode1(T_SKIPF,offset_then),then_code,makecode1(T_SKIP,offset_else),else_code,endcode());
}
#ifdef DEBUG_IF_STAT
printf("IF_STAT - exit\n");
#endif
return if_stat_code;
}
Code program(Pnode root)
{
Code body = stat_list(root->child);
Value v1; v1.ival = body.size + 2;
return concode(makecode1(T_TCODE, v1),
body,
makecode(T_HALT),
endcode());
}
Code if_stat(Pnode p)
{
/*
if
/
/
expr ---> stat_list [---> stat_list]
*/
Schema exprschema;
Code exprcode = expr(p->child, &exprschema);
Code bodythen = stat_list(p->child->brother);
// Vincoli semantici
if (exprschema.type != BOOLEAN)
semerror(p->child, "Boolean expression required");
if (p->child->brother->brother == NULL)
{
// IF-THEN
Value v1; v1.ival = bodythen.size + 1;
return concode(exprcode,
makecode1(T_SKIPF, v1),
bodythen,
endcode());
}
else
{
// IF-THEN-ELSE
Code bodyelse = stat_list(p->child->brother->brother);
Value v1; v1.ival = bodythen.size + 2;
Value v2; v2.ival = bodyelse.size + 1;
return concode(exprcode,
makecode1(T_SKIPF, v1),
bodythen,
makecode1(T_SKIP, v2),
bodyelse,
endcode()
);
}
}
// [RULE] stat: list EOF | assign EOF;
void stat() {
// check if stat is a list
if (stat_list()) {
list();
match(EOF_TYPE);
}
// check if stat is an assignment
else if (stat_assign()) {
assign();
match(EOF_TYPE);
} else
throw NoViableAltException(lookaheadType(1));
}
void stat_shutdown(struct pk_state *state, gboolean normal)
{
gchar **stats;
gchar **cur;
gchar *value;
if (normal) {
/* Log statistics */
for (stats = cur = stat_list(state); *cur != NULL; cur++) {
value = stat_get(state, *cur);
g_strchomp(value);
pk_log(LOG_STATS, "%s: %s", *cur, value);
g_free(value);
}
g_strfreev(stats);
}
g_hash_table_destroy(state->fuse->stat_buffers);
g_mutex_free(state->fuse->stat_buffer_lock);
}
Code while_stat(Pnode p)
{
/*
while
/
/
expr ---> stat_list
*/
Schema exprschema;
Code exprcode = expr(p->child, &exprschema);
Code body = stat_list(p->child->brother);
// Vincoli semantici
if (exprschema.type != BOOLEAN)
semerror(p->child, "Boolean expression required");
Value v1; v1.ival = body.size + 2;
Value v2; v2.ival = -(exprcode.size + body.size + 1);
return concode(exprcode,
makecode1(T_SKIPF, v1),
body,
makecode1(T_SKIP, v2),
endcode());
}
//语句
AST_node statement(AST_node parent)
{
AST_node t = makeNode(STATEMENT, parent);
if (symbol == IDENT)
{
//赋值语句或者过程调用语句
//<赋值语句>::=<标识符>:=<表达式>|<函数标识符>:=<表达式>|<标识符>'['<表达式>']':=<表达式>
//<过程调用语句>::=<标识符>[<实在参数表>]
match(IDENT,t);
if (symbol == BECOMES || symbol == LBRACKET)
{
//赋值语句
stat_assign(t);
}
else if (symbol == LPARENT || symbol == SEMICOLON
|| symbol == END //过程调用语句在end前,可以没有分号
)
{
//过程调用语句
stat_procedure(t);
}
else
{
error("Unknown Statement!");
recovery(2, SEMICOLON, END);
}
}
else if (symbol == IF)
{
//条件语句
//<条件语句>::=if<条件>then<语句>|if<条件>then<语句>else<语句>
stat_if(t);
}
else if (symbol == DO)
{
//当循环语句
//<当循环语句>::=do<语句>while<条件>
stat_do(t);
}
else if (symbol == FOR)
{
//for循环语句
//<for循环语句>::=for<标识符>:=<表达式>（downto|to）<表达式>do<语句>//步长为1
stat_for(t);
}
else if (symbol == BEGIN)
{
//复合语句
//<复合语句>::=begin<语句>{;<语句>}end
stat_list(t);
}
else if (symbol == READ)
{
//读语句
//<读语句>::=read'('<标识符>{,<标识符>}')'
stat_read(t);
}
else if (symbol == WRITE)
{
//写语句
//<写语句>::=write'('<字符串>,<表达式>')'|write'('<字符串>')'|write'('<表达式>')'
stat_write(t);
}
else
{
//空语句
t->ast_type = EMPTY;
printf("----------------Empty Statement--------------\n");
}
return 0;
}
/*Genera il codice per il nodo program*/
Code program(Pnode root){
Code body = stat_list(root->child);
//Prende body, gli mette TCODE prima e THALT dopo.
return concode(makecode1(T_TCODE, body.size + 2), body, makecode(T_HALT), endcode());
}
void program(){
match(PROGRAM);
stat_list();
match(END);
match(END_OF_FILE); //end of file
}
