编译原理词法分析器,ll1,lr0,python实现代码

1、-. z.计算机科学与通信工程学院编译原理实验报告题目： 1.词法分析器2. LL(1)分析器 3. LR(0)分析器班级：: *：指导教师：2017年月-. z.-. z.目录 TOC o 1-3 h z u HYPERLINK l _Toc483942693一、实验题目 PAGEREF _Toc483942693 h 1HYPERLINK l _Toc483942694二、实验目的和要求 PAGEREF _Toc483942694 h 1HYPERLINK l _Toc483942695三、代码实现 PAGEREF _Toc483942695 h 1HYPERLINK l _Toc4839

2、42696四、总结 PAGEREF _Toc483942696 h 1-. z.-. z.实验题目词法分析器分析一段程序代码，将代码中的单词符号分解出来，并对其进展检查，输出token表和error表LL(1)文法分析器分析给定文法。求出文法的FIRST集，FOLLOW集，并构建分析表，对给定输入串进展分析。LR(0)文法分析器分析给定文法。用_CLOSURE方法构造文法的LR(0)工程集规*族，根据状态转换函数GO构造出文法的DFA,并转换为分析表，对给定输入串进展分析。实验目的和要求学会词法分析器的实现思路。学会求解FIRST集， FOLLOW集，构造LL(1)分析表。学会_CLOSURE

3、方法，状态转换函数GO, 构造LR(0)分析表。代码实现词法分析器program.t*t 中存放要分析的文法：E-TRR-+TR|-TR|T-FGG-*FG|/FG|F-(E)|i：KEYWORD_LIST = while, if, else, switch, caseSEPARATOR_LIST = ;, :, , (, ), , , , OPERATOR_LIST1 = +, -, *OPERATOR_LIST2 = =, , =CATEGORY_DICT = # KEYWORD while: while: , if: if: , else: else: , switch: switch:

4、 , case: case: , # OPERATOR +: +: , -: -: , *: *: , =: relop: LE, =: relop: GE, : relop: GT, =: relop: EQ, =: =: , # SEPARATOR ;: ;: , : : , ,: ,: , (: (: , ): ): , : : , : : , : : , : : ,CONSTANTTABLE = TOKENTABLE = OPERATORTABLE = KEYWORDTABLE = SEPARATORTABLE = UNDEFINEDTABLE = # READ FILEdef rea

5、d_file(path, method): temp_str = try: file = open(path, method) for line in file: line = line.replace(n, ) temp_str += line temp_str = str(temp_str) e*cept IOError as e: print(e) e*it() finally: file.close() return temp_str.strip() + # GETBEdef getbe(): global token getchar() token = return# GETCHAR

6、def getchar(): global character global location while all_stringlocation = : location = location + 1 character = all_stringlocation return character# LINK TOKENdef concatenation(): global token global character token = token + character# IS NUMBERdef digit(): if 0 = character = 9: return True return

7、 False# IS ALPHABETdef letter(): if A = character = Z or a = character = z: return True return False# IS IDENTIFIERdef reserve(): if token in KEYWORD_LIST: return CATEGORY_DICTtoken else: return 0# RETRACTdef retract(): global location global character # location = location - 1 character = return# M

8、AIN FUNCTIONdef main(): global token global character global location s = getchar() getbe() if a = s = z or A = s = Z: while letter() or digit(): concatenation() location = location + 1 character = all_stringlocation retract() c = reserve() if c = 0: TOKENTABLE.append(token) print(这是标识符：, token, :,

9、TOKENTABLE.inde*(token), ) else: KEYWORDTABLE.append(token) print(这是保存字：, CATEGORY_DICTtoken) elif 0 = s = 9: while digit(): concatenation() location = location + 1 character = all_stringlocation retract() CONSTANTTABLE.append(token) print(这是常数：, token, :, CONSTANTTABLE.inde*(token), ) elif s in OPE

10、RATOR_LIST1: location = location + 1 OPERATORTABLE.append(s) print(这是单操作符：, CATEGORY_DICTs) elif s in OPERATOR_LIST2: location = location + 1 character = all_stringlocation if character = =: OPERATORTABLE.append(s + character) print(这是双操作符：, CATEGORY_DICTs + character) else: retract() location = loc

11、ation + 1 OPERATORTABLE.append(s) print(这是单操作符:, CATEGORY_DICTs) elif s in SEPARATOR_LIST: location = location + 1 SEPARATORTABLE.append(s) print(这是分隔符：, CATEGORY_DICTs) else: location += 1 UNDEFINEDTABLE.append(s) print(error:undefined identity :, s, )if _name_ = _main_: character = token = all_str

12、ing = read_file(program.t*t, r) location = 0 while location + 1 TRR-+TR|-TR|T-FGG-*FG|/FG|F-(E)|i输入串：i+i*i代码：NonTermSet = set() # 非终结符集合TermSet = set() # 终结符集合First = # First集Follow = # Follow集GramaDict = # 处理过的产生式Code = # 读入的产生式AnalysisList = # 分析表StartSym = # 开场符号EndSym = # # 完毕符号为#Epsilon = # 由于没

13、有epsilon符号用代替# 构造First集def getFirst(): global NonTermSet, TermSet, First, Follow, FirstA for * in NonTermSet: First* = set() # 初始化非终结符First集为空for * in TermSet: First* = set(*) # 初始化终结符First集为自己Change = True while Change: # 当First集没有更新则算法完毕Change = False for * in NonTermSet: for Y in GramaDict*: k =

14、0 Continue = True while Continue and k len(Y): if not FirstYk - set(Epsilon) 0: # Y1到Yi候选式都有存在Continue = False else: First* |= FirstYk - set(Epsilon) Change = True if Epsilon not in FirstYk: Continue = False k += 1 if Continue: # *-或者Y1到Yk均有产生式First* |= set(Epsilon) # FirstAY |= set(Epsilon)# 构造Foll

15、ow集def getFollow(): global NonTermSet, TermSet, First, Follow, StartSym for A in NonTermSet: FollowA = set() FollowStartSym.add(EndSym) # 将完毕符号参加Follow开场符号中Change = True while Change: # 当Follow集没有更新算法完毕Change = False for * in NonTermSet: for Y in GramaDict*: for i in range(len(Y): if Yiin TermSet: c

16、ontinue Flag = True for j in range(i + 1, len(Y): # continue if not FirstYj - set(Epsilon) = FollowYi: FollowYi |= FirstYj - set(Epsilon) # 步骤2 FIRST()/ 参加到FOLLOW(B)中。Change = True if Epsilon not in FirstYj: Flag = False break if Flag: if not Follow* ,把FOLLOW(A)加到FOLLOW(B)中FollowYi |= Follow* Change

17、 = True# 构造分析表def getAnalysisList(): for non* in NonTermSet: AnalysisListnon* = dict() row = AnalysisListnon* flag = True for Y in GramaDictnon*: for term in TermSet: if term in FirstY0 and term in Firstnon*: rowterm = non*+-+Y if Epsilon in Firstnon* and flag: flag = False for tmp in Follownon*: ro

18、wtmp = non*+-+Epsilon print(分析表:) for non* in NonTermSet: print( , non*, AnalysisListnon*)# 查询分析表def findAnalysisList(non, ter): try: tmp = AnalysisListnonter *, Y = tmp.split(-) e*cept E*ception as e: print(find error ) # MA,a为空，发现语法错误print(e) pass return Y# 显示格式def display(show_list): for item in

19、show_list: print( %-25s % item, end=) print()# LL(1)分析器def analyzer(): head = Stack, StackTop, NowStr, InputStr, Action # inputStr = i+i*i + EndSym inputStr = input(请输入表达式：) + EndSym print(分析过程：) display(head) stack = location = 0 stack.append(EndSym) stack.append(StartSym) stack_top = stack.pop() w

20、hile stack_top != EndSym and location ，只将A弹出mess = 弹出栈顶符号 + stack_top + 因M + stack_top + , + inputStrlocation + 中为 + stack_top mess = mess + -,故不压栈 else: # MA,a中的产生式右部符号串按逆序逐一压入栈中mess = 弹出栈顶符号 + stack_top + ,将M + stack_top + , + inputStr location + 中的 + stack_top + - + result + 的 + result mess = mes

21、s + 逆序压栈 tmp_list = for char in result: tmp_list.append(char) tmp_list.reverse() stack.e*tend(tmp_list) display(stack, stack_top, inputStrlocation, inputStrlocation + 1: len(inputStr), mess) stack_top = stack.pop() else: break if stack_top = EndSym and inputStrlocation = EndSym: # * = a = # 分析成功,分析器

22、停顿工作display(, #, #, , 匹配，分析成功) print() print(*) print(* Analysis Success *) print(*) else: print(Analysis Error)# 读取文法defreadGrammar(): try: file = open(grammar.t*t, r) for line in file: line = line.replace(n, ) Code.append(line) e*cept IOError as e: print(e) e*it() finally: file.close() return Code

23、# 初始化def init(): global NonTermSet, TermSet, First, Follow, StartSym, Code Code = readGrammar() n = int(len(Code) print(产生式个数:, n) StartSym = Code00 print(开场符号：, StartSym) print(产生式：G, StartSym, :) for i in range(n): *, Y = Codei.split(-) print( , Codei) NonTermSet.add(*) Y = Y.split(|) for Yi in Y:

24、 TermSet |= set(Yi) if * not in GramaDict: GramaDict* = set() GramaDict* |= set(Y) # 生成产生式集TermSet -= NonTermSet print(非终结符:, NonTermSet) print(终结符:, TermSet) getFirst() getFollow() print(FIRST集:) for k in NonTermSet: print( FIRST, k, : , Firstk) print(FOLLOW集:) for k, v in Follow.items(): print( FO

25、LLOW, k, : , v) TermSet -= set(Epsilon) TermSet |= set(EndSym) getAnalysisList() analyzer()init()运行结果：LR(0)分析器program.t*t 中存放要分析的文法：*-SS-BBB-aBB-b输入串：abab代码：VN = # 非终结符VT = # 终结符NFA = # NFA表DFA = # DFA表grammar = # 读入的文法doted_grammar = # 加点后的文法VN2Int = # 非终结符映射VT2Int = # 终结符映射action = # action表goto =

26、 # goto表DFA_node = # DFA节点表status_stack = # 状态栈symbol_stack = # 符号栈now_state = # 栈顶状态input_ch = # 栈顶字符input_str = # 输入串location = 0 # 输入位置now_step = 0 # 当前步骤# 读取文法def read_grammar(file_name): global grammar with open(file_name, r) as file: for line in file: line = line.replace(n, ) grammar.append(li

27、ne) file.close()# 找到终结符和非终结符def find_term_non(): global grammar n = int(len(grammar) temp_vt = l = 0 for i in range(n): *, Y = grammari.split(-) if * not in VN: VN.append(*) VN2Int.update(*: l) l += 1 for Yi in Y: temp_vt.append(Yi) m = 0 for i in temp_vt: if i not in VN and i not in VT: VT.append(i

28、) VT2Int.update(i: m) m += 1 VT.append(#) VT2Int.update(#: m)# 在字符串*个位置加点def add_char2str(grammar_i, i): grammar_i = grammar_i0:i + . + grammar_ii:len(grammar_i) return grammar_i# 给文法加点def add_dot(): global doted_grammar j = 0 n = 0 for i in grammar: for k in range(len(i) - 2): doted_grammar.append(

29、) doted_grammarn.append(add_char2str(i, k + 3) doted_grammarn.append(false) n += 1 j += 1# 显示加点后的文法def print_doted_grammar(): print(加点后的文法) j = 1for i in doted_grammar: print(%d.%s % (j, i0) j += 1# 显示读入文法def print_read_grammar(): print(读入的文法) j = 0 for i in grammar: print(%d)%s % (j, i) j += 1# 初始化

30、NFAdef init_NFA(): global NFA for row in range(len(doted_grammar): NFA.append() for col in range(len(doted_grammar): NFArow.append()# 找到点的位置def find_pos_point(one_grammar): return one_grammar.find(.)# 文法是否以start开头，以.开场defis_start(grammar_i, start): if grammar_i0.find(start, 0, 1) + grammar_i0.find(.

31、, 3, 4) = 3: return True else: return False# 查找以start开头，以.开场的文法,返回个数def find_node(start, grammar_id): num = 0 for i in doted_grammar: if is_start(i, start): grammar_idnum = doted_grammar.inde*(i) num += 1 return num# 构造NFAdef make_NFA(): global NFA grammar_id = for i in range(len(doted_grammar): gra

32、mmar_id.append() init_NFA() i = 0 for grammar_i in doted_grammar: pos_point = find_pos_point(grammar_i0) # 找到点的位置if not pos_point + 1 = len(grammar_i0): NFAii + 1 = grammar_i0pos_point + 1 if grammar_i0pos_point + 1 in VN: # 点后面跟着非终结符j = find_node(grammar_i0pos_point + 1, grammar_id) for k in range(

33、j): NFAigrammar_idk = * add_more(i, grammar_idk) i += 1# 查找关联def add_more(i, j): global NFA grammar_id = for k in range(len(doted_grammar): grammar_id.append() pos_point = find_pos_point(doted_grammarj0) if not pos_point + 1 = len(doted_grammarj0): if doted_grammarj0pos_point + 1 in VN: j = find_nod

34、e(doted_grammarj0pos_point + 1, grammar_id) for k in range(j): NFAigrammar_idk = * add_more(i, grammar_idk)# 显示NFAdef print_NFA(): global NFA, doted_grammar print(NFA邻接矩阵) print(end= ) for i in range(len(doted_grammar): print(%4d % (i + 1), end=) print() for i in range(len(doted_grammar): print(, en

35、d=) print() for i in range(len(doted_grammar): print(%3d| % (i + 1), end=) for j in range(len(doted_grammar): print(%4s % NFAij, end=) print() for l in range(len(doted_grammar): print(, end=) print()# 初始化DFAdef init_DFA(): global DFA for row in range(len(doted_grammar): DFA.append() for col in range

36、(len(doted_grammar): DFArow.append()# 连接def add_state(to, fro): for i in range(len(doted_grammar): if not NFAtoi = and not NFAtoi = *: DFAtoi = NFAtoi if not NFAfroi = and not NFAfroi = *: # from可连接的点DFAtoi = NFAfroi# 构造DFAdef make_DFA(): global NFA, doted_grammar, DFA_node init_DFA() for i in range

37、(len(doted_grammar): DFA_node.append() for j in range(len(doted_grammar): DFA_nodei.append() for i in range(len(doted_grammar): if doted_grammari1 = false: k = 0 DFA_nodeik = doted_grammari0 k += 1 doted_grammari1 = true for j in range(len(doted_grammar): if NFAij = *: # 有弧DFA_nodeik = doted_grammar

38、j0 k += 1 doted_grammarj1 = true add_state(i, j)# 显示DFAdef print_DFA(): global DFA, doted_grammar print(DFA邻接矩阵) print(end= ) for i in range(len(doted_grammar): print(%4d % (i + 1), end=) print() for i in range(len(doted_grammar): print(, end=) print() for i in range(len(doted_grammar): print(%3d| %

39、 (i + 1), end=) for j in range(len(doted_grammar): print(%4s % DFAij, end=) print() for l in range(len(doted_grammar): print(, end=) print()# 初始化LR分析表def init_LR_table(): global doted_grammar, action, goto for i in range(len(doted_grammar): action.append() goto.append() for j in range(len(VT): actio

40、ni.append() for j in range(len(VN): gotoi.append(-1)# 有无规约项def need_protocol(point): global DFA_node if not DFA_nodepoint0 = : for i in range(len(doted_grammar): if DFA_nodepointi.endswith(.): return DFA_nodepointi else: return None else: return None# 根据文法内容找到文法编号def find_grammar(string): global gra

41、mmar tmp = string0: len(string) - 1 for i in range(len(grammar): if tmp = grammari: return i# 填充LR分析表def fill_LR_table(): global doted_grammar, VT2Int, VN2Int, VN init_LR_table() for i in range(len(doted_grammar): if need_protocol(i): num = find_grammar(need_protocol(i) tmp = r + str(num) for j in r

42、ange(len(VT): if i = 1: actioniVT2Int# = acc else: actionij = tmp else: for j in range(len(doted_grammar): if not DFAij = : if DFAij in VN: gotoiVN2Int.get(DFAij, -1) = j else: tmp = s + str(j) actioniVT2Int.get(DFAij, -1) = tmp# 显示LR分析表def print_LR_table(): global VT, VN, doted_grammar, action, got

43、o # 表头print(LR分析表) print(tt|t, end=) print(%3s % ) * (len(VT) - 2), end=) print(Action, end=) print(%3s % ) * (len(VT) - 2), end=) print(t|t, end=) print(%3s % ) * (len(VN) - 2), end=) print(GOTO, end=) print(%3s % ) * (len(VN) - 2), end=) print(t|) print(ttt, end=) for i in VT: print(%3st % i, end=

44、) print(t|t, end=) k = 0 for i in VN: if not k = 0: print(%3st % i, end=) k += 1 print(t|) for i in range(len(doted_grammar): print(, end=) print() # 表体for i in range(len(doted_grammar): print(%5dt|t % i, end=) for j in range(len(VT): print(%4s % actionij, end=) print(t|t, end=) for j in range(len(V

45、N): if not j = 0: if not gotoij = -1: print(%4s % gotoij, end=) else: print(t, end=) print(t|) for i in range(len(doted_grammar): print(, end=) print()# 判断分析是否完成def is_end(): if input_strlocation:len(input_str) = #: if symbol_stack-1 = * and symbol_stack-2 = #: return True else: return False else: r

46、eturn False# 读入输入串def read_input(): global input_str input_str = input(输入串：) + # 输出def output(): global now_step, status_stack, symbol_stack, input_str, now_state print(%dtt % now_step, end=) now_step += 1 print(%-20s % status_stack, end=) print(%-25s % symbol_stack, end=) print(%-22s % input_strloc

47、ation:len(input_str), end=)# 统计产生式右部的个数def count_right_num(grammar_i): return len(grammar_i) - 3# 规约def do_stipulations(): global status_stack, input_str, symbol_stack, location, now_state, input_ch print(分析过程) print(步骤tt, end=) print(%-17s % 状态栈, end=) print(%-22s % 符号栈, end=) print(%-20s % 输入串, end=) print(动作说明) for i in range(len(doted_grammar): print(, end=) print() symbol_sta