Documentation for routine pred

Documentation for routine pred, assembled from the following types:

role Numeric

From Numeric

(Numeric) method pred

method pred(Numeric:D:)

Returns the number decremented by one (predecessor).

enum Bool

From Bool

(Bool) routine pred

method pred(--> Bool:D)

Returns False.

say True.pred;                                    # OUTPUT: «False␤» 
say False.pred;                                   # OUTPUT: «False␤» 

pred is short for "predecessor"; it returns the previous enum value. Bool is a special enum with only two values, False and True. When sorted, False comes first, so False is the predecessor to True. And since False is the "lowest" Bool enum value, its own predecessor is also False.

class Str

From Str

(Str) method pred

method pred(Str:D: --> Str:D)

Returns the string decremented by one.

String decrementing is "magical" just like string increment (see succ). It fails on underflow

'b0'.pred;           # RESULT: «a9» 
'a0'.pred;           # Failure 
'img002.png'.pred;   # RESULT: «img001.png» 

class Date

From Date

(Date) method pred

Defined as:

method pred(Date:D: --> Date:D)

Returns a Date of the previous day. "pred" is short for "predecessor".

say"2016-01-01").pred;   # OUTPUT: «2015-12-31␤»