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ArgumentMismatch

rascal-0.40.17

Synopsis​

The called signature does not match any defined function.

Description​

A function has a name and a signature (the names and types of its arguments). This error is reported when a call of a function cannot be associated with a function declaration.

Remedies:

  • Modify the call so that the arguments match the function declaration.
  • Write a new definition for a function with the same name, that matches the argument types in the call.

Examples​

Define a function triple that multiplies its argument by 3:

rascal>int triple(int x) = 3 * x;
int (int): function(|prompt:///|(0,26,<1,0>,<1,26>))

It works fine:

rascal>triple(5)
int: 15

Unless it is called with an argument of a wrong type:

rascal>triple([1,2,3])
|prompt:///|(12,1,<1,12>,<1,13>): CallFailed([[1,2,3]])
    at $shell$(|prompt:///|(0,9,<1,0>,<1,9>))
ok

We can define a new version of triple function that accepts lists:

rascal>list[int] triple(list[int] L) = [3 * x | x <- L];
list[int] (list[int]): function(|prompt:///|(0,49,<1,0>,<1,49>))
rascal>triple([1,2,3]);
list[int]: [3,6,9]