Name Rascal/Libraries/Prelude/List/toMapUnique

Synopsis Convert a list of tuples to a map; result must be a map.

Function map[&A,&B] toMapUnique(list[tuple[&A, &B]] lst) throws MultipleKey

Usage import List;

Description Convert a list of tuples to a map; result must be a map.

Examples

rascal>import List;
ok
rascal>toMapUnique([<1,10>, <2, 20>, <3, 30>]);
map[int, int]: (1:10,2:20,3:30)

Let's explore an error case:

rascal>toMapUnique([<1,10>, <1, 11>, <2, 20>, <3, 30>]);
|rascal://List|(27833,1003,<1353,0>,<1394,79>): MultipleKey(1)
	at *** somewhere ***(|rascal://List|(27833,1003,<1353,0>,<1394,79>))
	at toMapUnique(|stdin:///|(43,2,<1,43>,<1,45>))

Pitfalls The keys in a map are unique by definition. toMapUnique throws a MultipleKey exception when the list contains more than one tuple with the same first value.

Questions

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