public static ISymbol ToExpression(string expressionString, VariableContext context)
{
var tokens = Parse(expressionString, context);
var tb = new TreeBuilder(tokens, context);
return(tb.Parse());
}
/// <summary>
/// Adds definitions from intersecting variable names, substituting their
/// values into the context. Similar to running "Define" on the present
/// context from each defined variable in the other context.
/// </summary>
/// <param name="other"></param>
public void DefineFrom(VariableContext other)
{
foreach (var variableName in _initMap.Keys)
{
if (other.IsDefined(variableName))
{
Define(variableName, other.Get(variableName));
}
}
}
public static List <SymbolToken> Parse(string expression, VariableContext context)
{
var pipe1 = new StringToPrimitiveTokenPipe(expression, context);
var pipe2 = new MatchAllParenthesesProcessor(pipe1);
var pipe3 = new NegationProcessor(pipe2);
var pipe4 = new RedundantParenthesesProcessor(pipe3);
var pipe5 = new TokenValidater(pipe4);
return(pipe5.PumpAll());
}
/// <summary>
/// Identifies whether all variables in this context are
/// registered in the other context
/// </summary>
/// <param name="other"></param>
/// <returns></returns>
public bool IsSubsetOf(VariableContext other)
{
foreach (var variableName in _initMap.Keys)
{
if (!other.IsRegistered(variableName))
{
return(false);
}
}
return(true);
}
public TreeBuilder(List <SymbolToken> tokens, VariableContext ctx)
{
_tokens = TrimParentheses(tokens);
if (_tokens.Count == 0)
{
throw new ArgumentException("missing token", nameof(tokens));
}
if (_tokens.Count == 1 && !_tokens[0].Type.IsValue())
{
throw new ArgumentException(string.Format("hanging token: {0}", tokens[0].Token),
nameof(tokens));
}
_ctx = ctx;
}
public AlgebraProcessor(VariableContext context = null)
{
_variableContext = context ?? VariableContext.Default;
}
public StringToPrimitiveTokenPipe(IEnumerable <char> input, VariableContext ctx) : base(input)
{
_chars = new StringBuilder();
_ctx = ctx;
}
public StringToPrimitiveTokenPipe(string input, VariableContext ctx) : this(input.ToCharArray(), ctx)
{
}