/// <summary>
/// Helper extension to extract constants from an expression tree.
/// </summary>
/// <typeparam name="T">The type of constant to extract.</typeparam>
/// <param name="expressionEnumerator">The <see cref="IExpressionEnumerator"/> to parse.</param>
/// <exception cref="ArgumentNullException">Thrown when enumerator is null.</exception>
/// <returns>The <see cref="IEnumerable{ConstantExpression}"/> with
/// matching types.</returns>
public static IEnumerable <ConstantExpression> ConstantsOfType <T>(
this IExpressionEnumerator expressionEnumerator)
{
Ensure.NotNull(() => expressionEnumerator);
return(expressionEnumerator.OfType <ConstantExpression>()
.Where(ce => ce.Type == typeof(T)));
}
/// <summary>
/// Helper extension to extract nodes with a specific
/// <see cref="ExpressionType"/> value.
/// </summary>
/// <param name="expressionEnumerator">The <see cref="IExpressionEnumerator"/> to query.</param>
/// <param name="type">The <see cref="ExpressionType"/> to extract.</param>
/// <returns>The filtered result of <see cref="IEnumerable{Expression}"/>.</returns>
public static IEnumerable <Expression> OfExpressionType(
this IExpressionEnumerator expressionEnumerator, ExpressionType type)
{
Ensure.NotNull(() => expressionEnumerator);
return(expressionEnumerator
.Where(e => e.NodeType == type));
}
MethodsWithNameForType <T>(
this IExpressionEnumerator expressionEnumerator,
string name)
{
return(MethodsWithNameForType(
expressionEnumerator,
typeof(T),
name));
}
/// <summary>
/// Helper extension to extract methods with a particular name.
/// </summary>
/// <param name="expressionEnumerator">The <see cref="IExpressionEnumerator"/> to query.</param>
/// <param name="name">The method name to extract.</param>
/// <returns>The <see cref="IEnumerable{T}"/> result.</returns>
public static IEnumerable <MethodCallExpression> MethodsWithName(
this IExpressionEnumerator expressionEnumerator,
string name)
{
Ensure.NotNull(() => expressionEnumerator);
Ensure.NotNullOrWhitespace(() => name);
return(expressionEnumerator
.OfType <MethodCallExpression>()
.Where(mce => mce.Method.Name == name));
}
/// <summary>
/// Helper method to extract members with a name.
/// </summary>
/// <typeparam name="T">The type the member belongs to.</typeparam>
/// <param name="expressionEnumerator">The <see cref="IExpressionEnumerator"/>.</param>
/// <param name="name">The name of the member.</param>
/// <returns>The instances of <see cref="MemberExpression"/> that refer to it.</returns>
public static IEnumerable <MemberExpression> MembersWithNameOnType <T>(
this IExpressionEnumerator expressionEnumerator,
string name)
{
Ensure.NotNull(() => expressionEnumerator);
Ensure.NotNullOrWhitespace(() => name);
return(expressionEnumerator
.OfType <MemberExpression>()
.Where(me => me.Member.DeclaringType == typeof(T) &&
me.Member.Name == name));
}
MethodsWithNameForType(
this IExpressionEnumerator expressionEnumerator,
Type type,
string name)
{
Ensure.NotNull(() => expressionEnumerator);
Ensure.NotNullOrWhitespace(() => name);
return(expressionEnumerator
.OfType <MethodCallExpression>()
.Where(mce => mce.Method.DeclaringType == type &&
mce.Method.Name == name));
}
MethodsFromTemplate <T>(
this IExpressionEnumerator expressionEnumerator,
Expression <Action <T> > method)
{
Ensure.NotNull(() => method);
var lambda = method as LambdaExpression;
if (lambda.Body is MethodCallExpression mc)
{
if (mc.Method.DeclaringType == typeof(T))
{
return(MethodsWithNameForType <T>(
expressionEnumerator,
mc.Method.Name));
}
}
throw ExceptionHelper
.MethodCallOnTypeRequiredException(
nameof(method));
}