/// <summary>
/// Indicates that the given sub-expression is the next expected, giving it a
/// name and specifying whether it is required.
/// </summary>
/// <param name="itemName">The name that the token will be identified with in the outer expression.</param>
/// <param name="definition">The definition for the sub-expression.</param>
/// <returns>The updated expression.</returns>
public Options Add(string itemName, ExpressionDefinition definition)
{
if (definition == null)
{
throw new ArgumentNullException("definition");
}
IExpressionItem item = new Expression(definition);
options.Add(new ExpressionItem(itemName, false, item));
return this;
}
public List <LookaheadPropogation> DetermineLookaheads(ExpressionDefinition x)
{
List <LookaheadPropogation> result = new List <LookaheadPropogation>();
if (!Transitions.Keys.Contains(x))
{
return(result);
}
foreach (Item item in KernelItems())
{
ItemSet j = new ItemSet(
new List <Item>()
{
new Item(item.SubProduction,
0,
new HashSet <TerminalExpressionDefinition>()
{
new TerminalExpressionDefinition {
TokenType = TokenType.Hash
}
}
)
}
);
foreach (Item closureItem in j.KernelItems())
{
if (closureItem.ExpressionAfterDot != null &&
closureItem.ExpressionAfterDot.IsEqualTo(x))
{
Item i = Transitions[x].First(xx => xx.IsEqualTo(closureItem, true));
if (!closureItem.Lookahead.Any(y => y.TokenType == TokenType.Hash))
{
i.AddLookaheads(closureItem.Lookahead.Except(i.Lookahead));
}
else
{
result.Add(new LookaheadPropogation
{
FromItem = item,
FromSet = this,
ToSet = Transitions[x],
ToItem = i
});
}
}
}
}
return(result);
}
/// <summary>
/// Creates or retrieves the expression definition associated with the given name.
/// </summary>
/// <param name="type">The identifier to use to refer to the expression type later.</param>
/// <returns>The expression definition to allow for configuration.</returns>
public ExpressionDefinition Define(string type)
{
if (String.IsNullOrWhiteSpace(type))
{
throw new ArgumentException(Resources.BlankExpressionType, "type");
}
ExpressionDefinition definition;
if (!expressionLookup.TryGetValue(type, out definition))
{
definition = new ExpressionDefinition(type);
expressionLookup.Add(type, definition);
}
return definition;
}
public ExpressionInstanceVM()
{
Reset = new DelegateCommand<object>(ResetHandler);
Close = new DelegateCommand<object>(CloseHandler);
_inputs = new ObservableCollection<ObservableInputVM>();
Inputs = new ReadOnlyObservableCollection<ObservableInputVM>(_inputs);
if (IsInDesignMode())
{
Definition = new ExpressionDefinition("Zip", "To jest opis Zip ... ", "(a,b) => z.Zip(b, (x,y) => x + y)");
_inputs.Add(new ObservableInputVM());
Output = new ObservableOutputVM();
}
}
public ItemSet Goto(ExpressionDefinition expression)
{
ItemSet result = new ItemSet();
foreach (Item item in this)
{
if (item.ExpressionAfterDot != null &&
item.ExpressionAfterDot.IsEqualTo(expression))
{
Item cloned = item.Clone(true);
result.Add(cloned);
}
}
return(result.Closure());
}
internal static Expression Create(ExpressionDefinition x)
{
if (x is NonTerminalExpressionDefinition nted)
{
return(new NonTerminalExpression {
Identifier = nted.Identifier, Key = nted.Key
});
}
if (x is TerminalExpressionDefinition ted)
{
return(new TerminalExpression {
TokenType = ted.TokenType, Key = ted.Key
});
}
return(null);
}
/// <summary>
/// Initializes a new instance of an Expression.
/// </summary>
/// <param name="expression">The sequence of tokens and sub-expressions expected to appear.</param>
internal Expression(ExpressionDefinition expression)
{
this.expression = expression;
}
public ExpressionInstanceVM(ExpressionDefinition definition)
: this()
{
Definition = definition;
Reset.Execute(null);
}
/// <summary>
/// Creates a sub-expression definition.
/// </summary>
/// <returns>The expression definition to allow for configuration.</returns>
public ExpressionDefinition Define()
{
ExpressionDefinition definition = new ExpressionDefinition(null);
return definition;
}
public abstract bool IsEqualTo(ExpressionDefinition definition);
