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A number never changes type on its own, so every conversion is in the code

A number type names its width: i32, i64, u8, f64, and usize for lengths and indices. hd never converts between them for you, not even from i32 to the wider i64, so i64(quantity) shows each place a value changes type. A literal takes its type from its use, and _ groups digits, as in 1_250. Text that should be a number is parsed, and parsing can fail, so text.parse::[i32]() gives a Result. A string interpolates $name and ${expression}; a $ before anything else is plain text, so $${...} prints a dollar sign before the value. A range index slices: entry[0..3] is the first three bytes, and entry[4..] the rest from byte 4.

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fn order_line(entry: string, unit_cents: i64) -> string: sku := entry[0..3] # ← a range index slices: bytes 0, 1, 2 quantity := (entry[4..]).parse::[i32]().unwrap_or(1) # ← text to number, which may fail total := unit_cents * i64(quantity) # ← i32 to i64: you write the widening cents := (total % 100).to_string().pad_start(2, '0') "$sku x$quantity: $${total / 100}.$cents"pub fn main() -> void $ Console: println(order_line("LMP 3", 1_250)) # ← `_` groups digits println(order_line("BLB 12", 75)) println(order_line("CBL x", 1_999))# Change `i64(quantity)` to `quantity` and Run. hd never converts# a number for you, not even to a wider type:# type-mismatch: in operand: expected i64, found i32# ── plumbing ──