public static SList RetrieveSList(this SExpression[] expressions, SScope scope, string operationName)
{
SList list = null;
(expressions.Length == 1 && (list = expressions[0].Evaluate(scope) as SList) != null)
.OrThrows("<" + operationName + "> 必须是一个list");
return(list);
}
public static void Main(string[] arassaadgs)
{
new SScope(null) //这个相当于应用程序的全局作用域
.BuildIn("+", (arg, scope) => arg.Evaluate <SNumber>(scope).Sum(s => s))
.BuildIn("-", (arg, scope) =>
{
var numbers = arg.Evaluate <SNumber>(scope).ToArray();
var firstValue = numbers[0];
if (numbers.Length == 1)
{
return(-firstValue);
}
return(firstValue - numbers.Skip(1).Sum(s => s));
})
.BuildIn("*", (arg, scope) => arg.Evaluate <SNumber>(scope).Aggregate((a, b) => a * b))
.BuildIn("/", (arg, scope) =>
{
var numbers = arg.Evaluate <SNumber>(scope).ToArray();
var firstValue = numbers[0];
return(firstValue / numbers.Skip(1).Aggregate((a, b) => a * b));
})
.BuildIn("=", (args, scope) => args.ChainRelation(scope, (s1, s2) => (long)s1 == (long)s2))
.BuildIn(">", (args, scope) => args.ChainRelation(scope, (s1, s2) => s1 > s2))
.BuildIn("<", (args, scope) => args.ChainRelation(scope, (s1, s2) => s1 < s2))
.BuildIn(">=", (args, scope) => args.ChainRelation(scope, (s1, s2) => s1 >= s2))
.BuildIn("<=", (args, scope) => args.ChainRelation(scope, (s1, s2) => s1 <= s2))
.BuildIn("first", (args, scope) => args.RetrieveSList(scope, "first").First())
.BuildIn("rest", (args, scope) => new SList(args.RetrieveSList(scope, "rest").Skip(1)))
.BuildIn("append", (args, scope) =>
{
SList list0 = null, list1 = null;
(args.Length == 2 &&
(list0 = args[0].Evaluate(scope) as SList) != null &&
(list1 = args[1].Evaluate(scope) as SList) != null).OrThrows("请输入两个list类型的数据");
Debug.Assert(list1 != null, "list1 != null");
Debug.Assert(list0 != null, "list0 != null");
return(new SList(list0.Concat(list1)));
})
//开始读取数据code为读取的字符串
.KeepInterpretingInConsole((code, scope) => code.ParseAsIScheme().Evaluate(scope));
}
