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Strings

Strings are immutable Unicode text values written with double quotes. Escape a double quote or a backslash with a backslash.

var message = "say: \"hello\""
print(message)        # say: "hello"
print(message.size) # 12

size counts Unicode characters, not bytes; it is a property, not a method. Strings iterate by character, but they cannot be indexed with []; use index() or last_index() when a character position is needed.

var language = "Goblin"

for character in language {
    print(character)
}

Combining and converting text

Use + to concatenate strings. A string can also concatenate an integer or boolean, and * repeats it by an integer count, in either operand order.

print("go" + "blin") # goblin
print("item-" + 3)   # item-3
print("ha" * 3)      # hahaha
print(3 * "ha")      # hahaha

Str(value) converts any value to its display text. This is useful when building a string from a float, list, custom type, or nil.

var label = "port=" + Str(8080)
print(label)

Common string methods

MethodPurpose
sizeCharacter count (property)
upper() / lower() / title()Change letter case
contains(substring)Test for a substring
has_prefix(prefix) / has_suffix(suffix)Test the beginning or end
index(substring) / last_index(substring)Find a substring; returns -1 if absent
count(substring)Count non-overlapping occurrences
replace(old, new, count=-1)Replace all occurrences by default
split(separator, count=-1)Split into a list
split_after(separator, count=-1)Split while retaining separators
trim(cutset=nil)Trim Unicode whitespace or supplied characters
trim_prefix(prefix) / trim_suffix(suffix)Remove one matching edge
cut(separator)Split once, returning a three-element result
repeat(count)Repeat text

Methods accept named arguments as well as positional ones.

var title = "  Goblin book  "
print(title.trim().upper())
print("a,b,c".split(sep=",", count=2))
print("one one one".replace(old="one", new="two", count=2))
print("config.toml".trim_suffix(".toml"))

trim() with no argument removes Unicode whitespace. Supplying a string trims any of its characters from both ends; it does not remove an exact substring. Use trim_prefix() or trim_suffix() when that distinction matters.

Common text-processing patterns

Use trim() before validating user-supplied text, split() to turn a delimited setting into a list, and replace() when normalizing a known spelling or format.

var raw_tags = " go, language,tools "
var tags = []
for tag in raw_tags.split(",") {
    tags.push(tag.trim())
}
print(tags)

var filename = "report.TXT"
if filename.lower().has_suffix(".txt") {
    print("text file")
}

Use contains() when a yes/no answer is enough. Use index() or last_index() when you need the position, such as separating a filename from its final extension.