Text

String methods cover search, trimming, reshaping, splitting and joining, and comparison; for repeated concatenation there is StringBuilder. Unless noted, methods are read-only and return new strings.

Search and checks

val s = "Hello, Mush";
print(s.Length, s.IsEmpty, " ".IsNullOrWhiteSpace());
print(s.Contains("mus", true), s.StartsWith("Hell"), s.EndsWith("xyz"));
print(s.IndexOf("o"), s.IndexOf("o", 5), s.LastIndexOf("o"));

11 False True
True True False
4 -1 4

Contains / StartsWith / EndsWith / IndexOf all take an optional ignoreCase argument (case-insensitive comparison). IndexOf accepts a start index and returns -1 on a miss.

Trimming and reshaping

val s = "Hello, Mush";
print(s.Substr(7), s.Substr(0, 5), s.Substring(7, 2));
print(s.ToUpper(), s.ToLower());
print("  hi  ".Trim(), "hi".PadLeft(5, '.'), "ab".Repeat(3));
print(s.Replace("Mush", "World"));

Mush Hello Mu
HELLO, MUSH hello, mush
hi ...hi ababab
Hello, World

• Substr(start, length) runs to the end when length is omitted; Substring is an alias.
• Trim / TrimStart / TrimEnd strip whitespace.
• PadLeft / PadRight pad to the target width counting clusters.
• Repeat(n) repeats; a non-positive n yields the empty string.

Insertion, removal, and reversal

val s = "Hello, Mush";
print(s.Insert(5, "!!"), s.Remove(5));
print("abcdef".Reverse());

Hello!!, Mush Hello
fedcba

Remove(start, length) deletes to the end when length is omitted. Reverse reverses in cluster order, so multi-cluster characters are not torn apart.

Single-cluster access

val s = "Hello, Mush";
print(s.CharAt(7), "é".CodePointAt(0));

M 233

• CharAt(index) returns the index-th grapheme cluster (as a string); out of range reports MS6024.
• CodePointAt(index) returns the code point of the cluster’s first scalar.
• Get(index) is the corresponding fallible form: it fetches a cluster under the same grapheme-cluster semantics, failing with IndexOutOfRange when out of range.

val s = "héllo";
print(try? s.Get(1) ?? "?");
val t = "a🙂b";
print(try? t.Get(1) ?? "?");

é
🙂

CharAt / Get return a slice of the original string, so the result feeds straight into further string operations; for a single char value, use the indexer.

val family = "a👨‍👩‍👧b";
print(family[1] == '👨‍👩‍👧', family.CharAt(1) == "👨‍👩‍👧");

True True

Splitting and joining

print("a,b,,c".Split(","), "a,b,,c".Split(",", true));
print("1-2-3".Split("-"));
print(", ".Join(["a", "b"]));

[a, b, , c] [a, b, c]
[1, 2, 3]
a, b

Split(separator) returns a string[], keeping empty segments by default; a second argument of true drops them. Join’s receiver is the separator, and its argument is the sequence (arrays and lists are both accepted).

Comparison and miscellany

print("abc".Compare("abd"), "b".Compare("a"));

-1 1

Compare returns a negative number, zero, or a positive number to express order, and Equals(other, ignoreCase) does equality checks. String ordering comparisons use ordinal semantics; see operators.

StringBuilder

Heavy + concatenation inside a loop produces piles of intermediate strings. StringBuilder accumulates the pieces in an internal buffer and materializes them once at the end with ToString():

import Text.*;
 
val sb = new StringBuilder();
sb.Append("one");
sb.AppendLine("");
sb.Append("two ");
sb.Append("x");
print(sb.ToString());
print(sb.Length);
sb.Clear();
print(sb.Length, sb.ToString() == "");

one
two x
9
0 True

Append returns the builder itself, so calls chain; AppendLine(s) appends content plus a newline (the argument is required). StringBuilder lives in std’s Text module; to use the bare name you need import Text.*;.

Notes

• All indexes and lengths count grapheme clusters, not bytes or UTF-16 units — see Unicode and grapheme clusters.
• Numeric ToString(format) formats share one table with interpolation; see string interpolation.