中间代码生成(7)

}

void iteration_stmt() { match(WHILE, \ match('('); int to_begin = newlabel(); my_quads_code.gen_label(to_begin); int to_true = newlabel(); int to_false = newlabel(); condition_expression(to_true, to_false); match(')'); my_quads_code.gen_label(to_true); statement(); my_quads_code.gen_goto(to_begin); my_quads_code.gen_label(to_false); }

void return_stmt() { match(RETURN, \ if((*token_ix).get_token_type() == ';') { match(';'); my_quads_code.gen_uni(\ } else { string exp_name = expression(); match(';'); my_quads_code.gen_param_load(my_par_table_chain, \ } }

string expression() { vector::iterator reserve = token_ix; string ret; try{ ret = additive_expression(); }catch(logic_error e) { token_ix = reserve; string id_name = my_id_tab.get_lexeme(match(ID)); match('='); string right = expression(); my_quads_code.gen_bi(my_par_table_chain, id_name, right); ret = id_name; } return ret; }

void condition_expression(int to_true, int to_false) { string add_exp1 = additive_expression(); string relop_name; switch(match(RELOP)) {

case GE: relop_name = \ case GT: relop_name = \ case EQ: relop_name = \ case NE: relop_name = \ case LE: relop_name = \ case LT: relop_name = \ } string add_exp2 = additive_expression(); my_quads_code.gen_condition(my_par_table_chain, relop_name, add_exp1, add_exp2, to_true); my_quads_code.gen_goto(to_false); }

string additive_expression() { return additive_expressionR(term()); }

string additive_expressionR(string heir) { if((*token_ix).get_token_type() == ADDOP) { string addop_name; switch(match(ADDOP)) { case '+': addop_name = \ case '-': addop_name = \ } string term_name = term(); string n = my_par_table_chain.newtemp(); my_par_table_chain.enter(n, \ my_quads_code.gen_tri(my_par_table_chain, addop_name, n, heir, term_name); return additive_expressionR(n); } else return heir; }

string term() { return termR(factor()); }

string termR(string heir) { if((*token_ix).get_token_type() == MULOP) { string mulop_name; switch(match(MULOP)) { case '*': mulop_name = \ case '/': mulop_name = \ } string factor_name = factor(); string n = my_par_table_chain.newtemp(); my_par_table_chain.enter(n, \ my_quads_code.gen_tri(my_par_table_chain, mulop_name, n, heir, factor_name); return termR(n); }

else return heir; }

string factor() { if((*token_ix).get_token_type() == NUM) { return int_to_str(match(NUM)); } else if((*token_ix).get_token_type() == '(') { match('('); string temp = additive_expression(); match(')'); return temp; } else { vector::iterator reserve = token_ix; try{ return call(); }catch (logic_error e) { token_ix = reserve; string ret_temp = my_id_tab.get_lexeme(match(ID)); if((*token_ix).get_token_type() == '=') throw logic_error(\ else return ret_temp; } } }

string call() { string id_name = my_id_tab.get_lexeme(match(ID)); match('('); string ret = my_par_table_chain.newtemp(); my_par_table_chain.enter(ret, \ my_quads_code.gen_uni(\ if((*token_ix).get_token_type() != ')') args(); match(')'); my_quads_code.gen_call(my_par_table_chain, id_name); return ret; }

void args() { string add_exp_name = additive_expression(); my_quads_code.gen_param_load(my_par_table_chain, \ if((*token_ix).get_token_type() == ',') { match(','); args(); } else ; }

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