150 lines
4.3 KiB
C#
150 lines
4.3 KiB
C#
// Copyright (c) Ivan Bondarev, Stanislav Mikhalkovich (for details please see \doc\copyright.txt)
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// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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using PascalABCCompiler;
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using PascalABCCompiler.SyntaxTree;
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namespace SyntaxVisitors
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{
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public class CheckVariablesRedefenitionVisitor : WalkingVisitorNew
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{
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private ISet<string> UpperBlockNames { get; set; }
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// Map :: CurrentLevel -> { BlockNames }
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private List<ISet<string>> BlockNamesStack { get; set; }
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private int CurrentLevel = -1;
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public CheckVariablesRedefenitionVisitor(ISet<string> upperBlockNames)
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{
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//this.UpperBlockNames = upperBlockNames;
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this.UpperBlockNames = new HashSet<string>();
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this.BlockNamesStack = new List<ISet<string>>(10);
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}
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public override void visit(formal_parameters fp)
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{
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foreach (var id in fp.params_list.SelectMany(tp => tp.idents.idents))
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{
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CheckVariableAlreadyDefined(id);
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UpperBlockNames.Add(id.name);
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}
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}
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public override void visit(variable_definitions vd)
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{
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foreach (var id in vd.var_definitions.SelectMany(vds => vds.vars.idents))
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{
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CheckVariableAlreadyDefined(id);
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UpperBlockNames.Add(id.name);
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}
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base.visit(vd);
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}
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/*
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* // Scope Level 0
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* begin
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* var x = value; // Name in Scope Level 0
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* // Scope Level 1
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* begin
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* var x = value; // Name in Scope Level 1 <-- REDEFENITION ERROR, x defined at Level 0
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*
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* var y = value;
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* var y = value2; // Name in Scope Level 1 <-- REDEFINITION ERROR, y defined at Level 1
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*
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* // Scope Level 2
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* begin
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* var z = y; // Name in Scope Level 2
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* end
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* // Scope Level 2
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* begin
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* var z = value; // Name in Scope Level 2
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* end
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* end
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*
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* end
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*/
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public override void visit(statement_list stlist)
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{
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++CurrentLevel;
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if (BlockNamesStack.Count <= CurrentLevel)
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{
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// Создаем множество имен для текущего уровня вложенности мини-пространства имен
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BlockNamesStack.Add(new HashSet<string>());
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}
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base.visit(stlist);
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//for (var i = 0; i < stlist.list.Count; ++i)
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// ProcessNode(stlist.list[i]);
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BlockNamesStack.RemoveAt(BlockNamesStack.Count - 1);
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--CurrentLevel;
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}
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public override void visit(var_statement vs)
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{
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foreach (var id in vs.var_def.vars.idents)
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{
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// Проверяем есть ли такое имя выше?
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CheckVariableAlreadyDefined(id);
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BlockNamesStack[CurrentLevel].Add(id.name);
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}
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base.visit(vs);
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}
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public override void visit(for_node fn)
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{
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if (fn.create_loop_variable)
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{
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CheckVariableAlreadyDefined(fn.loop_variable);
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}
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base.visit(fn);
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}
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public override void visit(foreach_stmt frch)
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{
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if (frch.type_name != null)
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{
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CheckVariableAlreadyDefined(frch.identifier);
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}
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base.visit(frch);
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}
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private bool IsVariableAlreadyDefined(string name)
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{
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if (UpperBlockNames.Contains(name))
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return true;
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for (int i = 0; i <= CurrentLevel; ++i)
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{
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if (BlockNamesStack[i].Contains(name))
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return true;
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}
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return false;
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}
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private void CheckVariableAlreadyDefined(ident id)
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{
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string name = id.name;
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if (IsVariableAlreadyDefined(name))
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{
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throw new SyntaxVisitorError("Var_{0}_is_already_defined", id.source_context, name);
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}
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}
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}
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}
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