================================================================================
If then else
================================================================================

if 12 then 27 else 42

--------------------------------------------------------------------------------

(source_file
  (if_expression
    condition: (integer_literal)
    consequence: (integer_literal)
    alternative: (integer_literal)))

================================================================================
If then
================================================================================

if 12 then 27

--------------------------------------------------------------------------------

(source_file
  (if_expression
    condition: (integer_literal)
    consequence: (integer_literal)))

================================================================================
Dangling else
================================================================================

if 12 then if 27 then 42 else "nope"

--------------------------------------------------------------------------------

(source_file
  (if_expression
    condition: (integer_literal)
    consequence: (if_expression
      condition: (integer_literal)
      consequence: (integer_literal)
      alternative: (string_literal))))