ludic/docs/language/text/text-char_at.md

id	name	category	kind	tokens	sig	tip	order	ns	member
text-char_at	Text.char_at	text	namespace-method	Text.char_at	Text.char_at(s, i) -> int	The byte value at an index, 0..255.	1	Text	char_at

Returns the byte at position i in s as an int in the range 0..255 — for example Text.char_at("hello", 0) is 104, the code for h. Indices are zero-based and count bytes. Use it to inspect or classify individual characters, such as testing whether a key of input is a digit.

Parameters:

• s — the string to read from
• i — the zero-based byte index

program FirstIsDigit {
  let entry: string = "7up"

  handler Check phase Update {
    let c = Text.char_at(entry, 0)
    let is_digit = c >= 48 and c <= 57   # true: '7'
  }
}