/// <summary>
/// Creates the lambda expression from the statements attached to this entry and the parameter definitions in the provided program context.
/// </summary>
public LambdaExpression CreateLambda(VisualProgram context)
{
if (!context.Environment.EntryDefinitions.TryGetValue(VisualEntryId, out var def))
{
throw new KeyNotFoundException($"Could not find an entry with ID '{VisualEntryId}' in the VisualProgram's entry definitions.");
}
// Create a parameter for each expected/defined parameter
var parameters = def.Parameters.Map(Expression.Parameter);
return(Expression.Lambda(
Expression.Block(
// Before doing the main body of the entry function, make expressions to copy the incoming parameters to variables
ParameterMap
.Where(mapping => !string.IsNullOrWhiteSpace(mapping.Value)) // Exclude any that don't actually map to anything
.Select(p => VariableAccessorFactory.CreateSetterExpression(
context,
VariableReference.Create(def.Parameters[p.Key], p.Value),
parameters[p.Key]
)
).Concat(
// Then do the actual main body
NodeUtils.FlattenExpressions(context, FirstStatement)
)
),
// All lambdas will get a context parameter
// We also pass the defined parameters to the lambda so it knows what types to expect and what signature to have.
// This needs to happen regardless or not of whether the parameters are actually used by the entry function as this determines the delegate's signature.
new[] { context.Variables.compiledInstanceParameter }.Concat(parameters)
));
}
/// <summary>Resolves this reference into a single <see cref="BlockExpression"/> containing all the sequential statements.
/// If there are no statements that would end up in the block, throws an exception.</summary>
/// <exception cref="Exception"></exception>
public BlockExpression ResolveRequiredStatement(VisualProgram context)
{
var body = NodeUtils.FlattenExpressions(context, this);
if (body.Count() == 0)
{
throw new Exception(); // TODO Add meaningful message
}
return(Expression.Block(expressions: body));
}
public void Validate(VisualProgram context)
{
if (string.IsNullOrWhiteSpace(Name))
{
throw new Exception(); // TODO: Add meaningful error message. If this is thrown, variable isn't provided
}
if (!context.Variables.TryGetVariable(Name, out var def))
{
throw new Exception(); // TODO: Add meaninful error message. If this is thrown, could not find a variable with the target name.
}
if (def.Type != Type)
{
throw new Exception(); // TODO: Add meaningful message. If this is thrown, variable is wrong type
}
}
/// <summary>Gets the Linq Expression for this node.</summary> /// <param name="context">The program context. Required for variables, resolving links, etc.</param> public abstract Expression CreateExpression(VisualProgram context);
public Expression ResolveRequiredExpression(VisualProgram context) => ResolveExpression(context) ?? throw new Exception();
public Expression?ResolveExpression(VisualProgram context) => isValue
? Expression.Constant(value, typeof(TValue))
: nodeId.HasValue ? context.Nodes[nodeId.Value]?.CreateExpression(context) : null;
public VisualNode ResolveRequiredNode(VisualProgram context) => ResolveNode(context) ?? throw new Exception();
#pragma warning restore CS8653
public VisualNode?ResolveNode(VisualProgram context) => isValue || !nodeId.HasValue ? null : context.Nodes[nodeId.Value];
/// <summary>Alias for <see cref="CreateLambda(VisualProgram)"/>.</summary> public override Expression CreateExpression(VisualProgram context) => CreateLambda(context);
public Expression?ResolveSetterExpression(VisualProgram context, Expression value)
{
try { return(ResolveRequiredSetterExpression(context, value)); } catch { return(null); }
}
public Expression ResolveRequiredSetterExpression(VisualProgram context, Expression value) => VariableAccessorFactory.CreateSetterExpression(context, this, value);
public Expression?ResolveGetterExpression(VisualProgram context)
{
try { return(ResolveRequiredGetterExpression(context)); } catch { return(null); }
}
public Expression ResolveRequiredGetterExpression(VisualProgram context) => VariableAccessorFactory.CreateGetterExpression(context, this, typeof(TVar));
/// <summary>Resolves this reference into a single <see cref="BlockExpression"/> containing all the sequential statements.</summary> public BlockExpression ResolveStatement(VisualProgram context) => Expression.Block(expressions: NodeUtils.FlattenExpressions(context, this));
public Expression?ResolveExpression(VisualProgram context) => ResolveNode(context)?.CreateExpression(context);
public VisualNode?ResolveNode(VisualProgram context) => context.Nodes[nodeId];
