String list workaround for now

[sa-]

Hey, since we can't make DynamicVectors of Strings yet, I came up with a small append-only way to deal with lists of strings, and I thought I'd post it here in case it is useful to anyone else

from Vector import DynamicVector
from String import String

struct StringList:
    var data: String
    var offsets: DynamicVector[Int]
    
    fn __init__(inout self):
        self.data = String("")
        self.offsets = DynamicVector[Int]()
        self.offsets.push_back(0)
    
    fn append(inout self, s: String):
        self.data += s
        self.offsets.push_back(len(self.data))
        
    fn __getitem__(self, i: Int) -> String:
        let start_idx = self.offsets[i]
        let end_idx = self.offsets[i+1]
        let value: String = self.data[start_idx:end_idx]
        return value
    
    fn __len__(self) -> Int:
        return self.offsets.__len__() - 1

var sl = StringList()
sl.append("a")
sl.append("")
sl.append("b")
print(sl[0])
print(sl[1])
print(sl[2])
print(sl.__len__())

Output:

a

b
3