多层每层多个过程嵌套和调用.txt

一个pascal子集编译器。输入pascal原程序

program mini;
var a;
	procedure fun1;
	var b;
	begin read(a,b) end 
	procedure fun2;
	var c;
		procedure fun3;
		var d;
		begin read(a,c,d) end
		procedure fun4;
		var e;
		begin read(a,c,e) end
	begin read(a,c) end
begin
read(a);
call fun1;
call fun2;
call fun3;
call fun4
end.