Control Flow (If, Switch, and Switch Expressions) - CPULL/Dflat GitHub Wiki

Control Flow

If Statements

Conditional branching using if, else if, and else.

  • Parentheses: Parentheses around the conditional expression are not required.
  • Syntax: An if statement is followed by a block { ... } or a single instruction prefixed with a then.
if a > 0 {
} else {
}
if a > 0 then jump done // Single statement, same line, no else

Switch Statement

Value branching via switch.

  • Case Values: Supports literals, enum entries, sets (e.g., 3, 4, 5:), and ranges (e.g., 400..=499:, ..=-1:, 1..:).
  • No Fall-Through: There is no automatic fall-through between cases.
  • Jumping: Inside a switch, jump name targets another case, while jump #name# targets an explicit label. A jump loop between cases triggers a level 1 warning.
switch val {
  1: one(), 2: two()
  3, 4, 5: { b = 1; b++ }
  6..=9:
    b = 2
    jump 3
  Red: jump 3
  default: jump #out#
}

Switch Expressions

Yielding values directly from a switch expression using the ? operator.

bool res = val ? { 1: true, default: false }
string yn = ok ? { "yes", "no" } // Equivalent to the ternary operator in other languages
i32 sign = value ? { ..=-1: -1, 0: 0, 1..: 1 }
  • Cases: Case values can be literals, enum entries, sets, and ranges (..=-1:, 1..:, 400..=499:).
  • Bodies: A case body can be a block, a statement on the same line (multiple cases can share a line separated by commas), or statements on the following lines up to the next case.