void statement(void)
{
token tok = next_token();
expr_rec source,target;
switch (tok){
case ID:
/*<statement> ::= ID := <expression>; */
match(ID);
target = process_id();
match(ASSIGNOP);
expression(& source);
match(SEMICOLON);
assign(target,source);
break;
case READ:
/*<statement> ::= READ (<id list>); */
match(READ); match(LPAREN);
id_list(); match(RPAREN);
match(SEMICOLON);
break;
case WRITE:
/*<statement> ::= WRITE (<expr list>); */
match(WRITE); match(LPAREN);
expr_list(); match(RPAREN);
match(SEMICOLON);
break;
default:
syntax_error(tok);
break;
}
}
int statement(int count)
{
char buffer[200];
token * begin;
begin=c;
memset(buffer, 0, sizeof buffer);
//ID:=<expression>;
if(c->token_number == ID)
{
advance();
if(c->token_number == ASSIGNOP)
{
advance();
if(expression())
{
//advance();
if(c->token_number == SEMICOLON)
{
advance();
while(c!=begin)
{
//fprintf(of_d.temp1, "Token number %d\tToken type %s\t\tActual %s\n", begin->token_number, begin->token_type, begin->buffer);
sprintf(buffer+strlen(buffer),"%s",begin->buffer);
begin=(token *) begin->next;
}
//fprintf(of_d.temp1,"\nPROGRAM LINE: %s\n\n\n",buffer);
//fprintf(of_d.listing_file, "%d:\t%s\n", count, buffer);
//valid statement
return 1;
}
else
{
printf("Missing semicolon\n");
return 0;
}
}
else
{
//keep increment pointer until after ;?
printf("Invalid expression\n");
return 0;
}
}
else
{
//keep increment pointer until after ;?
printf("Missing assignment operator\n");
return 0;
}
}
//READ(<id_list>);
else if (c->token_number == READ)
{
advance();
if (c->token_number == LPAREN)
{
if(id_list()==1)
{
advance();
if (c->token_number == RPAREN)
{
advance();
if (c->token_number == SEMICOLON)
{
advance();
while(c!=begin)
{
//fprintf(of_d.temp1, "Token number %d\tToken type %s\t\tActual %s\n", begin->token_number, begin->token_type, begin->buffer);
sprintf(buffer+strlen(buffer),"%s",begin->buffer);
begin=(token *) begin->next;
}
//fprintf(of_d.temp1,"\nPROGRAM LINE: %s\n\n\n",buffer);
//valid statement
return 1;
}
else
{
printf("Missing semicolon\n");
return 0;
}
}
else
{
printf("Missing right parentheses\n");
return 0;
}
}
else
{
printf("Expected at least one identifier\n");
return 0;
}
}
else
{
printf("Expected left parentheses\n");
return 0;
}
}
//WRITE(<expr_list>);
else if (c->token_number == WRITE)
{
advance();
if (c->token_number == LPAREN)
{
advance();
if(expr_list()==1)
{
if (c->token_number == RPAREN)
{
advance();
if (c->token_number == SEMICOLON)
{
advance();
while(c!=begin)
{
//fprintf(of_d.temp1, "Token number %d\tToken type %s\t\tActual %s\n", begin->token_number, begin->token_type, begin->buffer);
sprintf(buffer+strlen(buffer),"%s",begin->buffer);
begin=(token *) begin->next;
}
//fprintf(of_d.temp1,"\nPROGRAM LINE: %s\n\n\n",buffer);
//valid statement
return 1;
}
else
{
printf("Missing semicolon\n");
return 0;
}
}
}
else
{
printf("Invalid expression in list\n");
return 0;
}
}
else
{
printf("Expected left parentheses\n");
return 0;
}
}
//else not a statement
else
{
//printf("Not a statement\n");
return 0;
}
}