127 lines
3.1 KiB
C#
127 lines
3.1 KiB
C#
using System.Diagnostics.CodeAnalysis;
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namespace Canon.Core.SemanticParser;
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/// <summary>
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///符号表类
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/// </summary>
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public class SymbolTable
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{
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/// <summary>
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/// 符号表
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/// </summary>
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private readonly Dictionary<string, Symbol> _symbols = [];
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/// <summary>
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/// 类型表
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/// </summary>
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private readonly TypeTable _typeTable = new();
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/// <summary>
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/// 父符号表
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/// </summary>
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private readonly SymbolTable? _parent;
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/// <summary>
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/// 获得当前符号表的所有父符号表
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/// </summary>
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public IEnumerable<SymbolTable> ParentTables => GetParents();
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public SymbolTable() {}
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private SymbolTable(SymbolTable parent)
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{
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_parent = parent;
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}
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public SymbolTable CreateChildTable()
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{
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return new SymbolTable(this);
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}
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/// <summary>
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/// 尝试向符号表中添加符号
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/// </summary>
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/// <param name="symbol">欲添加的符号</param>
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/// <returns>是否添加成功</returns>
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public bool TryAddSymbol(Symbol symbol) => _symbols.TryAdd(symbol.SymbolName, symbol);
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/// <summary>
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/// 尝试从符号表极其父符号表查找符号
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/// </summary>
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/// <param name="name">需要查找的符号名称</param>
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/// <param name="symbol">查找到的符号</param>
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/// <returns>是否查找到符号</returns>
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public bool TryGetSymbol(string name, [NotNullWhen(true)] out Symbol? symbol)
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{
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if (_symbols.TryGetValue(name, out symbol))
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{
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return true;
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}
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foreach (SymbolTable table in ParentTables)
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{
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if (table._symbols.TryGetValue(name, out symbol))
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{
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return true;
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}
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}
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symbol = null;
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return false;
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}
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/// <summary>
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/// 从符号表极其父表的类型表中查找类型
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/// </summary>
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/// <param name="typeName">欲查找的类型名称</param>
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/// <param name="type">查找到的类型</param>
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/// <returns>是否查找到类型</returns>
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public bool TryGetType(string typeName, [NotNullWhen(true)] out PascalType? type)
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{
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if (_typeTable.TryGetType(typeName, out type))
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{
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return true;
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}
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foreach (SymbolTable parent in ParentTables)
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{
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if (parent._typeTable.TryGetType(typeName, out type))
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{
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return true;
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}
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}
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type = null;
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return false;
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}
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/// <summary>
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/// 尝试获得父符号表
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/// </summary>
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/// <param name="parent">获得的父符号表</param>
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/// <returns>是否存在父符号表</returns>
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public bool TryGetParent([NotNullWhen(true)] out SymbolTable? parent)
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{
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if (_parent is null)
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{
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parent = null;
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return false;
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}
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parent = _parent;
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return true;
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}
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private IEnumerable<SymbolTable> GetParents()
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{
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SymbolTable? now = _parent;
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while (now is not null)
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{
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yield return now;
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now = now._parent;
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}
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}
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}
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