/// <summary>
/// 构造产生式。
/// </summary>
/// <param name="symbolMapper">符号的映射表。</param>
public void BuildProductions(Dictionary <T, Symbol <T> > symbolMapper)
{
int len = bodies.Length;
productions = new Production <T> [len];
for (int i = 0; i < len; i++)
{
ProductionBody <T> body = bodies[i];
int cnt = body.Body.Count;
Symbol <T>[] symbolBody = new Symbol <T> [cnt];
for (int j = 0; j < cnt; j++)
{
T id = body.Body[j];
Symbol <T> sym;
if (symbolMapper.TryGetValue(id, out sym))
{
symbolBody[j] = sym;
}
else if (EqualityComparer <T> .Default.Equals(id, Token <T> .Error))
{
symbolBody[j] = Error;
}
else
{
throw CompilerCommonExceptions.InvalidSymbolId("body", id.ToString());
}
}
Terminal <T> prec = null;
if (body.PrecedenceSet)
{
Symbol <T> sym;
if (!symbolMapper.TryGetValue(body.Precedence, out sym))
{
throw CompilerCommonExceptions.InvalidSymbolId("Precedence", body.Precedence.ToString());
}
prec = sym as Terminal <T>;
if (prec == null)
{
throw CompilerCommonExceptions.InvalidSymbolId("Precedence", body.Precedence.ToString());
}
}
else
{
// 使用最右的终结符代表当前产生式的结合性。
for (int j = symbolBody.Length - 1; j >= 0; j--)
{
Terminal <T> sym = symbolBody[j] as Terminal <T>;
if (sym != null)
{
prec = sym;
break;
}
}
}
productions[i] = new Production <T>(body.Index, this, symbolBody, body.ProductionAction, prec);
}
}
/// <summary>
/// 拒绝当前的匹配，并尝试寻找下一个匹配。如果找不到下一个匹配，则会返回错误。
/// </summary>
public void Reject()
{
if (!this.rejectable)
{
throw CompilerCommonExceptions.NotRejectable();
}
if (this.reader.IsAccept)
{
throw CommonExceptions.ConflictingRejectAction();
}
this.reader.IsReject = true;
}
/// <summary>
/// 检查指定符号的标识符。
/// </summary>
/// <param name="id">要检查的标识符。</param>
public void CheckSymbolId(T id)
{
if (EqualityComparer <T> .Default.Equals(id, Token <T> .EndOfFile) ||
EqualityComparer <T> .Default.Equals(id, Token <T> .Error))
{
throw CompilerCommonExceptions.InvalidSymbolId("id", id.ToString());
}
else if (Constants.ToInt32(id) < 0)
{
throw CompilerCommonExceptions.InvalidSymbolId("id", id.ToString());
}
if (symbolIds.ContainsKey(id))
{
throw CompilerCommonExceptions.DuplicatedSymbolId("id", id.ToString());
}
}
/// <summary>
/// 返回产生式体。
/// </summary>
/// <param name="bodies">产生式体包含的终结符或非终结符。</param>
/// <returns>产生式体。</returns>
public ProductionBody <T> Body(params T[] bodies)
{
for (int i = 0; i < bodies.Length; i++)
{
if (EqualityComparer <T> .Default.Equals(bodies[i], Token <T> .EndOfFile))
{
throw CompilerCommonExceptions.InvalidSymbolId("bodies", bodies[i].ToString());
}
else if (!EqualityComparer <T> .Default.Equals(bodies[i], Token <T> .Error) &&
Constants.ToInt32(bodies[i]) < 0)
{
throw CompilerCommonExceptions.InvalidSymbolId("bodies", bodies[i].ToString());
}
}
return(new ProductionBody <T>(productionCount++, bodies ?? new T[0]));
}
/// <summary>
/// 解析指定正则表达式中定义的上下文。
/// </summary>
/// <param name="regex">要解析的正则表达式。</param>
/// <returns>正则表达式中定义的上下文。</returns>
private static IEnumerable <string> ParseContexts(ref string regex)
{
if (regex[0] == '<' && regex.IndexOf("<<EOF>>", StringComparison.OrdinalIgnoreCase) != 0)
{
// 处理上下文。
int idx = regex.IndexOf('>');
if (idx == -1)
{
throw CompilerCommonExceptions.IncompleteLexerContext("regex");
}
string contextStr = regex.Substring(1, idx - 1);
regex = regex.Substring(idx + 1);
if (contextStr != "*")
{
return(contextStr.Split(','));
}
}
return(new string[0]);
}