Add a definite iteration statement (e.g., like for in C or C++) to the language definition and your translator.
###BNF:
```
program ::= block
block ::= declaration_list statement_list
declaration_list ::= {declaration}
statement_list ::= {statement}
declaration ::= ’@’ id { ’,’ id }
statement ::= assignment | print | do | if | for
print ::= ’!’ expr
assignment ::= ref_id ’=’ expr
ref_id ::= [ ’ ̃’ [ number ] ] id
do ::= ’<’ guarded_command ’’
if ::= ’[’ guarded_command { ’|’ guarded_command } [ ’%’ block ] ’]’
for ::= ‘{’ [declaration] ‘;’ assignment ‘;’ expr ‘;’ assignment ‘:’ block ’}’
guarded_command ::= expr ’:’ block
expr ::= term { addop term }
term ::= factor { multop factor }
factor ::= ’(’ expr ’)’ | ref_id | number
addop ::= ’+’ | ’-’
multop ::= ’*’ | ’/’
```
###Description:
“for” is declared as:
```
for ::= ‘{’ [declaration] ‘;’ assignment ‘;’ expr ‘;’ assignment ‘:’ block ’}’
```
The usual format for for_loop is “for(int i=0; i<5; i++){}”,
then we break the for_loop into three parts,
1)initialization (declaration and assignment);
2)condition (expression);
3)increment/decrement (assignment);
4)body of loop (block);
note: declaration can be optional inside the loop since you can declare it outside and initialize it inside the loop
‘{’ : TK.FOR
‘}’ : TK.ENDFOR
‘;’ : TK.NEXT
':' : TK.THEN
Parsing Function will look like:
```
private void for_loop(){
mustbe(TK.FOR);
if(is(TK.DECLARE)){
declaration();
}
mustbe(TK.NEXT); //read in ';'
assignment(); //initialization
mustbe(TK.NEXT);
expr(); //condition
assignment(); //increment/decrement
mustbe(TK.THEN);
block();
}
```
Parsing Function with Translation to C:
```
private void for_loop(){
mustbe(TK.FOR);
/****translation to C****/
System.out.println("for (");
/************************/
if(is(TK.DECLARE)){
declaration();
}
mustbe(TK.NEXT); //read in ';'
assignment(); //initialization
/****translation to C****/
System.out.println(";");
/************************/
mustbe(TK.NEXT);
expr(); //condition
/****translation to C****/
System.out.println(";");
/************************/
assignment(); //increment/decrement
/****translation to C****/
System.out.println(")");
System.out.println("{");
/************************/
mustbe(TK.THEN);
block();
/****translation to C****/
System.out.println("}");
/************************/
}
