Name Rascal/Expressions/Values/List/Splice

Synopsis Splice the elements of a list in an enclosing list.

Syntax *Exp

Types

Exp	Exp1	Expn	[Exp1, ..., Exp, ..., Expn]
T	T1	Tn	list[lub(T1, ..., T, ...,Tn)]

Description The operator * splices the elements of a list in an enclosing list.

Examples Consider the following list in which the list [10, 20, 30] occurs as list element. It has as type list[value]:

rascal>[1, 2, [10, 20, 30], 3, 4];
list[value]: [
  1,
  2,
  [10,20,30],
  3,
  4
]

The effect of splicing the same list element in the enclosing list gives a flat list of type list[int]:

rascal>[1, 2, *[10, 20, 30], 3, 4];
list[int]: [1,2,10,20,30,3,4]

The same example can be written as:

rascal>L = [10, 20, 30];
list[int]: [10,20,30]
rascal>[1, 2, *L, 3, 4];
list[int]: [1,2,10,20,30,3,4]

Benefits The splicing operator gives full, explicit, control over the way in which nested lists are handled.

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