Ternary Expression

A ternary expression is a conditional expression that evaluates to a boolean value. It is also referred to as a "conditional expression," "ternary operator," or sometimes "inline if." It is a shorthand way of writing an if statement. It is written as follows:

var result = value_if_true if condition else value_if_false

For example:

var player_expression := "normal" if health > 5 else "hurt"

In this example, player_expression will be "normal" if the variable health is greater than 5, and "hurt" otherwise.

Ternary expressions can be combined, at the cost of readability. For example:

var player_expression := "normal" if health > 5 else "hurt" if health > 2 else "dead"

It might be more readable to break down the lines and use parentheses to make the order of evaluation explicit:

var player_expression := "normal" \
  if health > 5 \
  else \
  ( "hurt" \
    if health > 2 \
    else "dead"
  )

For something like this, you would probably use an if statement or a match statement instead, but this style can be useful when coding in a "branchless" way and ensuring a variable always has a value. Consider the below:

var user_message = null
if server_response == "ok":
  user_message = "Success! You're connected"
elif server_response == "error":
  user_message = "Error! Couldn't connect"

In this case, if the server answers something other than "ok" or "error", user_message will be null. We can use a ternary expression to ensure user_message always has a value:

var user_message := "Success! You're connected" \
  if server_response == "ok" \
  else "Error! Couldn't connect"

But even then, it's probably better to code defensively

A potentially more useful way to avoid the above snag is to do this:

var user_message := "Error! Couldn't connect"
if server_response == "ok":
  user_message = "Success! You're connected"

This way, if the server response is neither "ok" nor "error", user_message will still have a value.