Fuzion • Tutorial • Conditional Expression

Conditional Expression

Internally if/else desugars to a match expression. See syntax sugar for more information.

The if expression provides a simple control flow mechanism to chose between two branches. Its use is straightforward:

print_count(count i32, item String) unit
pre
  count >= 0
=>
  if count = 0
    yak "no"
  else
    yak count
  yak " $item"
  if count != 1
    yak "s"
  say ""

print_count 3 "apple"
print_count 1 "pear"
print_count 0 "apple"
print_count 2 "pear"

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print_count(count i32, item String) unit
pre
  count >= 0
=>
  if count = 0
    yak "no"
  else
    yak count
  yak " $item"
  if count != 1
    yak "s"
  say ""
print_count 3 "apple"
print_count 1 "pear"
print_count 0 "apple"
print_count 2 "pear"
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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What are effects?

A conditional expression can form the else clause of a previous conditional expression:

print_count(count i32, item String) unit
pre
  count >= 0
=>
  (cnt, plural) :=
    if      count = 0 ("no"  , $"s")
    else if count = 1 ("one" , "" )
    else              ($count, $"s")
  say "$cnt $item$plural"

print_count 3 "apple"
print_count 1 "pear"
print_count 0 "apple"
print_count 2 "pear"

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print_count(count i32, item String) unit
pre
  count >= 0
=>
  (cnt, plural) :=
    if      count = 0 ("no"  , $"s")
    else if count = 1 ("one" , "" )
    else              ($count, $"s")
  say "$cnt $item$plural"
print_count 3 "apple"
print_count 1 "pear"
print_count 0 "apple"
print_count 2 "pear"
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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What are effects?

Singeline If Expressions

Keyword then is often required in single-line if-expressions:

x := if true || false && true then "yes" else "no"

say x

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x := if true || false && true then "yes" else "no"
say x
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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What are effects?

last changed: 2024-06-28

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