MustacheSharp/mustache-sharp/ConditionTagDefinition.cs

102 lines
3.4 KiB
C#

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
namespace Mustache
{
/// <summary>
/// Defines a tag that conditionally prints its content.
/// </summary>
internal abstract class ConditionTagDefinition : ContentTagDefinition
{
private const string conditionParameter = "condition";
/// <summary>
/// Initializes a new instance of a ConditionTagDefinition.
/// </summary>
/// <param name="tagName">The name of the tag.</param>
protected ConditionTagDefinition(string tagName)
: base(tagName, true)
{
}
/// <summary>
/// Gets the parameters that can be passed to the tag.
/// </summary>
/// <returns>The parameters.</returns>
protected override IEnumerable<TagParameter> GetParameters()
{
return new TagParameter[] { new TagParameter(conditionParameter) { IsRequired = true } };
}
/// <summary>
/// Gets the tags that come into scope within the context of the current tag.
/// </summary>
/// <returns>The child tag definitions.</returns>
protected override IEnumerable<string> GetChildTags()
{
return new string[] { "elif", "else" };
}
/// <summary>
/// Gets whether the given tag's generator should be used for a secondary (or substitute) text block.
/// </summary>
/// <param name="definition">The tag to inspect.</param>
/// <returns>True if the tag's generator should be used as a secondary generator.</returns>
public override bool ShouldCreateSecondaryGroup(TagDefinition definition)
{
return new string[] { "elif", "else" }.Contains(definition.Name);
}
/// <summary>
/// Gets whether the primary generator group should be used to render the tag.
/// </summary>
/// <param name="arguments">The arguments passed to the tag.</param>
/// <returns>
/// True if the primary generator group should be used to render the tag;
/// otherwise, false to use the secondary group.
/// </returns>
public override bool ShouldGeneratePrimaryGroup(Dictionary<string, object> arguments)
{
object condition = arguments[conditionParameter];
return isConditionSatisfied(condition);
}
private bool isConditionSatisfied(object condition)
{
if (condition == null)
{
return false;
}
IEnumerable enumerable = condition as IEnumerable;
if (enumerable != null)
{
return enumerable.Cast<object>().Any();
}
if (condition is Char)
{
return (Char)condition != '\0';
}
try
{
decimal number = (decimal)Convert.ChangeType(condition, typeof(decimal));
return number != 0.0m;
}
catch
{
return true;
}
}
/// <summary>
/// Gets the parameters that are used to create a new child context.
/// </summary>
/// <returns>The parameters that are used to create a new child context.</returns>
public override IEnumerable<TagParameter> GetChildContextParameters()
{
return new TagParameter[0];
}
}
}