编译原理课程设计 编译器 C#实现

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace 编译原理 { public class SLR1Scanner { /// <summary> /// 文法集 /// </summary> private List<Product> DFAGrammer; /// <summary> /// 文法条数 /// </summary> private int count; /// <summary> /// 非终结符集 /// </summary> private string left = "SEFT"; /// <summary> /// 终结符 /// </summary> private string vt = "i+-*/()#"; /// <summary> /// 状态DFA集 /// </summary> private List<ItemList> statusDFA; public SLR1Scanner(List<Product> a) { this.DFAGrammer = a; count = DFAGrammer.Count; statusDFA = new List<ItemList>(); statusDFA.Clear(); } /// <summary> /// 初始化活前缀的DFA规范集 /// </summary> public void Init_DFA() { ItemList itemList = new ItemList(); itemList.Clear(); itemList.Add(DFAGrammer[0]); //圆点后是非终结符 if (left.IndexOf(itemList.getItem(0).Right.Substring(0, 1)) != -1) { foreach (Product p in DFAGrammer) { itemList.Add(p); } } statusDFA.Add(itemList); DFA(0); } private bool Contains(Item coreItem) { foreach (ItemList it in statusDFA) { if(it.getItem (0).Right == coreItem.Right && it.getItem (0).Left == coreItem.Left && it.getItem (0).Pos == coreItem.Pos) { return true; } } return false; } /// <summary> /// 计算活前缀状态集 /// </summary> /// <param name="index"></param> private void DFA(int index) { ItemList itemList = statusDFA[index]; ItemList temp_Item = getCopyOfItems(itemList); foreach (Item item in temp_Item.Items) { //归约项目 if (item.Right.Length == item.Pos) { continue; } ItemList temp_list = new ItemList(); item.Pos++; temp_list.Add(item); if (Contains(item)) { continue; } statusDFA.Add(temp_list); DFAElements(temp_list); } if (index < statusDFA.Count - 1) {// 直到不再增大为止 DFA(index + 1); } } public static ItemList getCopyOfItems(ItemList list) { ItemList ret = new ItemList(); foreach (Item i in list.Items) { Item item = new Item(i.Left, i.Right, i.Pos); ret.Add(item); } return ret; } private void DFAElements(ItemList temp_list) { Item item = temp_list.getItem(0); int pos = item.Pos; if (item.Right.Length == pos) return; if(left.IndexOf (item.Right.Substring (pos,1) )!= -1) { string ri = item.Right.Substring(pos, 1); List<Product> p_list = getProductByRight(ri); foreach (Product p in p_list) { temp_list.Add(p); } } } public string DisplayDFA() { string text = ""; for (int i = 0; i < statusDFA.Count; i++) { text += "I" + i.ToString()+"\n"; foreach (Item item in statusDFA[i].Items) { text += item.ToString() + "\n"; } } return text; } private List<Product> getProductByRight(string ri) { List<Product> pp = new List<Product>(); pp.Clear(); foreach (Product p in DFAGrammer) { if (p.Left == ri) { pp.Add(p); } } return pp; } } }