16498Snate@binkert.org# ----------------------------------------------------------------------------- 26498Snate@binkert.org# yacc_literal.py 36498Snate@binkert.org# 46498Snate@binkert.org# Grammar with bad literal characters 56498Snate@binkert.org# ----------------------------------------------------------------------------- 66498Snate@binkert.orgimport sys 76498Snate@binkert.org 86498Snate@binkert.orgif ".." not in sys.path: sys.path.insert(0,"..") 96498Snate@binkert.orgimport ply.yacc as yacc 106498Snate@binkert.org 116498Snate@binkert.orgfrom calclex import tokens 126498Snate@binkert.org 136498Snate@binkert.org# Parsing rules 146498Snate@binkert.orgprecedence = ( 156498Snate@binkert.org ('left','+','-'), 166498Snate@binkert.org ('left','*','/'), 176498Snate@binkert.org ('right','UMINUS'), 186498Snate@binkert.org ) 196498Snate@binkert.org 206498Snate@binkert.org# dictionary of names 216498Snate@binkert.orgnames = { } 226498Snate@binkert.org 236498Snate@binkert.orgdef p_statement_assign(t): 246498Snate@binkert.org 'statement : NAME EQUALS expression' 256498Snate@binkert.org names[t[1]] = t[3] 266498Snate@binkert.org 276498Snate@binkert.orgdef p_statement_expr(t): 286498Snate@binkert.org 'statement : expression' 296498Snate@binkert.org print(t[1]) 306498Snate@binkert.org 316498Snate@binkert.orgdef p_expression_binop(t): 326498Snate@binkert.org '''expression : expression '+' expression 336498Snate@binkert.org | expression '-' expression 346498Snate@binkert.org | expression '*' expression 356498Snate@binkert.org | expression '/' expression 366498Snate@binkert.org | expression '**' expression ''' 376498Snate@binkert.org if t[2] == '+' : t[0] = t[1] + t[3] 386498Snate@binkert.org elif t[2] == '-': t[0] = t[1] - t[3] 396498Snate@binkert.org elif t[2] == '*': t[0] = t[1] * t[3] 406498Snate@binkert.org elif t[2] == '/': t[0] = t[1] / t[3] 416498Snate@binkert.org 426498Snate@binkert.orgdef p_expression_uminus(t): 436498Snate@binkert.org 'expression : MINUS expression %prec UMINUS' 446498Snate@binkert.org t[0] = -t[2] 456498Snate@binkert.org 466498Snate@binkert.orgdef p_expression_group(t): 476498Snate@binkert.org 'expression : LPAREN expression RPAREN' 486498Snate@binkert.org t[0] = t[2] 496498Snate@binkert.org 506498Snate@binkert.orgdef p_expression_number(t): 516498Snate@binkert.org 'expression : NUMBER' 526498Snate@binkert.org t[0] = t[1] 536498Snate@binkert.org 546498Snate@binkert.orgdef p_expression_name(t): 556498Snate@binkert.org 'expression : NAME' 566498Snate@binkert.org try: 576498Snate@binkert.org t[0] = names[t[1]] 586498Snate@binkert.org except LookupError: 596498Snate@binkert.org print("Undefined name '%s'" % t[1]) 606498Snate@binkert.org t[0] = 0 616498Snate@binkert.org 626498Snate@binkert.orgdef p_error(t): 636498Snate@binkert.org print("Syntax error at '%s'" % t.value) 646498Snate@binkert.org 656498Snate@binkert.orgyacc.yacc() 666498Snate@binkert.org 676498Snate@binkert.org 686498Snate@binkert.org 696498Snate@binkert.org 70