/// <summary>
/// Create a new incremental symbolic regex builder.
/// </summary>
/// <param name="solver">Effective Boolean algebra over S.</param>
public SymbolicRegexBuilder(ICharAlgebra <S> solver)
{
this.solver = solver;
this.epsilon = SymbolicRegex <S> .MkEpsilon(this);
this.nothing = SymbolicRegex <S> .MkFalse(this);
singletonCache[solver.False] = this.nothing;
this.dot = SymbolicRegex <S> .MkTrue(this);
singletonCache[solver.True] = this.dot;
this.dotStar = SymbolicRegex <S> .MkDotStar(this, this.dot);
this.startAnchor = SymbolicRegex <S> .MkStartAnchor(this);
this.endAnchor = SymbolicRegex <S> .MkEndAnchor(this);
this.eolAnchor = SymbolicRegex <S> .MkEolAnchor(this);
this.bolAnchor = SymbolicRegex <S> .MkBolAnchor(this);
this.newLine = SymbolicRegex <S> .MkNewline(this);
singletonCache[this.newLine.set] = this.newLine;
this.bolRegex = SymbolicRegex <S> .MkLoop(this, SymbolicRegex <S> .MkConcat(this, this.dotStar, this.newLine), 0, 1);
this.eolRegex = SymbolicRegex <S> .MkLoop(this, SymbolicRegex <S> .MkConcat(this, this.newLine, this.dotStar), 0, 1);
}
/// <summary>
/// Make a concatenation of given regexes, if any regex is nothing then return nothing, eliminate
/// intermediate epsilons
/// </summary>
public SymbolicRegex <S> MkConcat(params SymbolicRegex <S>[] regexes)
{
if (regexes.Length == 0)
{
return(this.epsilon);
}
var sr = regexes[regexes.Length - 1];
if (sr.IsNothing)
{
return(this.nothing);
}
else
{
//exclude epsilons from the concatenation
for (int i = regexes.Length - 2; i >= 0; i--)
{
if (regexes[i].IsNothing)
{
return(this.nothing);
}
else if (sr.IsEpsilon)
{
sr = regexes[i];
}
else if (!regexes[i].IsEpsilon)
{
sr = SymbolicRegex <S> .MkConcat(this, regexes[i], sr);
}
}
return(sr);
}
}
