code / tomo

   1 '\" t
   2 .\" Copyright (c) 2026 Bruce Hill
   3 .\" All rights reserved.
   4 .\"
   5 .TH Table.get_or_set 3 2026-03-08 "Tomo man-pages"
   6 .SH NAME
   7 Table.get_or_set \- get an item or set a default if absent
   8 .SH LIBRARY
   9 Tomo Standard Library
  10 .SH SYNOPSIS
  11 .nf
  12 .BI Table.get_or_set\ :\ func(t:\ &{K:V},\ key:\ K,\ default:\ V\ ->\ V?)
  13 .fi
  14 .SH DESCRIPTION
  15 If the given key is in the table, return the associated value. Otherwise, insert the given default value into the table and return it.
  16 
  17 
  18 .SH ARGUMENTS
  19 
  20 .TS
  21 allbox;
  22 lb lb lbx
  23 l l l.
  24 Name	Type	Description
  25 t	&{K:V}	The table. 
  26 key	K	The key whose associated value is to be retrieved. 
  27 default	V	The default value to insert and return if the key is not present in the table. 
  28 .TE
  29 .SH RETURN
  30 Either the value associated with the key (if present) or the default value. The table will be mutated if the key is not already present.
  31 
  32 .SH NOTES
  33 If no default value is provided explicitly, but the table has a default value associated with it, the table's default value will be used.
  34 The default value is only evaluated if the key is missing.
  35 
  36 .SH EXAMPLES
  37 .EX
  38 t := &{"A": @[1, 2, 3]; default=@[]}
  39 t.get_or_set("A").insert(4)
  40 t.get_or_set("B").insert(99)
  41 assert t["A"][] == [1, 2, 3, 4]
  42 assert t["B"][] == [99]
  43 assert t.get_or_set("C", @[0, 0, 0])[] == [0, 0, 0]
  44 .EE
  45 .SH SEE ALSO
  46 .BR Tomo-Table (3)