LL1语法生成器-编译原理

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复制粘贴了别的大佬的界面，代码如下：

class GuiWidget(QWidget): # gui程序内容，相应按键，显示输出 def __init__(self, name): super().__init__()#调用父类 self.qle = QLineEdit(self) self.qle.setText('') self.qle.move(100, 20) self.qbt = QPushButton(self) self.qbt.setText('确认') self.qbt.move(250, 20) self.qtw_result = QTableWidget(20, 4, self) header = ['分析栈', '剩余输入串', '所用产生式', '动作'] self.qtw_result.setHorizontalHeaderLabels(header) self.qtw_result.setEditTriggers(QTableWidget.NoEditTriggers) self.qtw_result.horizontalHeader().setSectionResizeMode(QHeaderView.Stretch) self.qtw_result.verticalHeader().setSectionResizeMode(QHeaderView.Stretch) self.qtw_result.resize(600, 600) self.qtw_result.move(0, 50) self.qbt.clicked.connect(self.onInputChanged) self.setWindowTitle(name) self.show() def onInputChanged(self): text = self.qle.text() if text == '': return getGram() getVT() getVN() initail() getFirst() getFollow() creat_Select() analyse(text) row = -1 for num in massage: row += 1 col = -1 for item in num: col += 1 self.qtw_result.setItem(row, col, QTableWidgetItem(item)) 

构建first集

# 获取first集 def getFirst(): while (1): test = FIRST.copy() for i in sentences: temp0 = i.split("->")[0] temp1 = i.split("->")[1] if (temp0 in VT) or (temp1[0] in VT) or (temp1[0] == 'ε'): if (temp0 in VT): FIRST[temp0] = FIRST.get(temp0) else: FIRST[temp0] = FIRST.get(temp0) + temp1[0] else: # 首字符为非终结符 flag = 1 for j in temp1: FIRST[temp0] = FIRST.get(temp0) + str(FIRST[j]).replace('ε', '') if 'ε' not in FIRST[j]: # 若不含空集则break flag = 0 break if flag == 1: FIRST[temp0] = FIRST.get(temp0) + 'ε' for i, j in FIRST.items(): temp = "" for word in list(set(j)): temp += word FIRST[i] = temp if test == FIRST: break print(FIRST) 

构建follow集

def getFollow(): while (1): test = FOLLOW.copy() for i in sentences: temp0 = i.split("->")[0] temp1 = i.split("->")[1] for p in temp1: if p in VT or p == 'ε': continue local = temp1.find(p) flag0 = 0 # 判断是否为终结符 flag1 = 0 for j in temp1[local + 1:]: FOLLOW[p] = FOLLOW.get(p) + str(FIRST[j]).replace('ε', '') if 'ε' not in FIRST[j] or j in VT: if j in VT: flag0 = 1 else: flag1 = 1 break if (flag1 == 0) and (flag0 == 0): FOLLOW[p] = FOLLOW.get(p) + FOLLOW.get(temp0) for i, j in FOLLOW.items(): temp = "" for word in list(set(j)): temp += word FOLLOW[i] = temp if test == FOLLOW: break print(FOLLOW) 

构建分析表

# 像二维字典插入数据 def addDict(dict, a, b, val): if a in dict: dict[a].update({ 
   b: val}) else: dict.update({ 
   a: { 
   b: val}}) # 构建预测分析表 def creat_Select(): print(sentences) for sentence in sentences: a=sentence.split("->")[0] str=sentence.split("->")[1] temp=str[0] for i in VT: if i in FIRST[temp]: addDict(SELECT, a, i, str) if 'ε' in FIRST[temp]: for j in FOLLOW[a]: addDict(SELECT, a, j, 'ε') print(SELECT) 

以下为全部代码

import sys from inspect import stack from PyQt5.QtWidgets import (QWidget, QLineEdit, QApplication, QTableWidget, QTableWidgetItem, QPushButton, QHeaderView) VT = [] # 终结符 VN = [] # sentences = [] # 语法 file = "text.txt" Start = 'E' FIRST = { 
   } # first集 FOLLOW = { 
   } # follow 集 SELECT = { 
   "": { 
   "": ""}} # 分析表 STACK = ["#"] # 输入栈 STACK_INPUT = [] # 剩余输入串 massage = [] def getGram(): with open(file, encoding='UTF-8') as f: text = f.read().splitlines() print(text) for sentence in text: Start = sentence[0] if len(sentence.split('|')) < 2: sentences.append(sentence) else: part_head = sentence.split('|')[0] sentences.append(part_head) for i in sentence.split('|')[1:]: sentences.append(part_head[0] + "->" + i) print(sentences) # 获取VN def getVN(): for i in sentences: if i[0] not in VN: VN.append(i[0]) VN.sort() print(VN) # 获取VT def getVT(): for i in sentences: for j in i: if not j.isupper(): if not j in VT: VT.append(j) VT.remove('ε') VT.sort() print(VT) def initail(): for str in sentences: part_begin = str.split("->")[0] part_end = str.split("->")[1] FIRST[part_begin] = "" FOLLOW[part_begin] = "" for i in VT: FIRST[i] = i FOLLOW[i] = i FIRST['ε'] = 'ε' FOLLOW['ε'] = 'ε' FOLLOW[Start] = '#' # 获取first集 def getFirst(): while (1): test = FIRST.copy() for i in sentences: temp0 = i.split("->")[0] temp1 = i.split("->")[1] if (temp0 in VT) or (temp1[0] in VT) or (temp1[0] == 'ε'): if (temp0 in VT): FIRST[temp0] = FIRST.get(temp0) else: FIRST[temp0] = FIRST.get(temp0) + temp1[0] else: # 首字符为非终结符 flag = 1 for j in temp1: FIRST[temp0] = FIRST.get(temp0) + str(FIRST[j]).replace('ε', '') if 'ε' not in FIRST[j]: # 若不含空集则break flag = 0 break if flag == 1: FIRST[temp0] = FIRST.get(temp0) + 'ε' for i, j in FIRST.items(): temp = "" for word in list(set(j)): temp += word FIRST[i] = temp if test == FIRST: break print(FIRST) # 获取follow集 def getFollow(): while (1): test = FOLLOW.copy() for i in sentences: temp0 = i.split("->")[0] temp1 = i.split("->")[1] for p in temp1: if p in VT or p == 'ε': continue local = temp1.find(p) flag0 = 0 # 判断是否为终结符 flag1 = 0 for j in temp1[local + 1:]: FOLLOW[p] = FOLLOW.get(p) + str(FIRST[j]).replace('ε', '') if 'ε' not in FIRST[j] or j in VT: if j in VT: flag0 = 1 else: flag1 = 1 break if (flag1 == 0) and (flag0 == 0): FOLLOW[p] = FOLLOW.get(p) + FOLLOW.get(temp0) for i, j in FOLLOW.items(): temp = "" for word in list(set(j)): temp += word FOLLOW[i] = temp if test == FOLLOW: break print(FOLLOW) # 像二维字典插入数据 def addDict(dict, a, b, val): if a in dict: dict[a].update({ 
   b: val}) else: dict.update({ 
   a: { 
   b: val}}) # 构建预测分析表 def creat_Select(): print(sentences) for sentence in sentences: a=sentence.split("->")[0] str=sentence.split("->")[1] temp=str[0] for i in VT: if i in FIRST[temp]: addDict(SELECT, a, i, str) if 'ε' in FIRST[temp]: for j in FOLLOW[a]: addDict(SELECT, a, j, 'ε') print(SELECT) def record(left1, key='', string=''): msg = "" for s in STACK: msg += s if key == '': b = '' c = 'GETNEXT' else: b = '{}->{}'.format(key, string) c = 'POP,PUSH({})'.format(string) massage.append([msg,left1, b, c]) def analyse(text): #STACK_INPUT = input(print("Please input: "))+"#" STACK_INPUT=text+"#" STACK.append(Start) index = 0 a = STACK_INPUT[index] x = STACK.pop() while not a == x == '#': if x in VN: fm = SELECT[x][a] for c in reversed(fm): if c != 'ε': STACK.append(c) record(STACK_INPUT[index:], x, fm) else: if a in VT: if x != a: # 出错 STACK.append(x) print("111") # error(STACK[index:], a, index + 1) break index += 1 a = STACK_INPUT[index] record(STACK_INPUT[index:]) x = STACK.pop() print("步骤 分析栈 剩余输入串 所用产生式 动作") count=1 for i in massage: print('{:<5}'.format(count),'{:<8}'.format(i[0]),'{:>7}'.format(i[1]),'{:^13}'.format(i[2]),'{:<13}'.format(i[3])) count+=1 ''' class GuiWidget(QWidget): # gui程序内容，相应按键，显示输出 def __init__(self, name): super().__init__()#调用父类 self.qle = QLineEdit(self) self.qle.setText('') self.qle.move(100, 20) self.qbt = QPushButton(self) self.qbt.setText('确认') self.qbt.move(250, 20) self.qtw_result = QTableWidget(20, 4, self) header = ['分析栈', '剩余输入串', '所用产生式', '动作'] self.qtw_result.setHorizontalHeaderLabels(header) self.qtw_result.setEditTriggers(QTableWidget.NoEditTriggers) self.qtw_result.horizontalHeader().setSectionResizeMode(QHeaderView.Stretch) self.qtw_result.verticalHeader().setSectionResizeMode(QHeaderView.Stretch) self.qtw_result.resize(600, 600) self.qtw_result.move(0, 50) self.qbt.clicked.connect(self.onInputChanged) self.setWindowTitle(name) self.show() def onInputChanged(self): text = self.qle.text() if text == '': return getGram() getVT() getVN() initail() getFirst() getFollow() creat_Select() analyse(text) row = -1 for num in massage: row += 1 col = -1 for item in num: col += 1 self.qtw_result.setItem(row, col, QTableWidgetItem(item)) def main(): name = 'LL1' app = QApplication(sys.argv) ex = GuiWidget(name) sys.exit(app.exec_()) #sys.exit(0) if __name__ == '__main__': sys.exit(main()) ''' if __name__ == '__main__': getGram() getVT() getVN() initail() getFirst() getFollow() creat_Select() analyse()