Sets in Delphi

A bike repair kit held as a set of TTool, edited and then questioned with in.

program SetsMembership;
type
  TTool = (TireLever, Pump, ChainTool, Patch, Wrench);
  TKit = set of TTool;       // a set holds any combination of those values
var
  Kit: TKit;
begin
  Kit := [TireLever, Patch];
  Include(Kit, Pump);        // Include adds one value, Exclude removes one
  Exclude(Kit, Patch);
  Kit := Kit + [Wrench];     // + unions two sets, - subtracts one
  if Pump in Kit then        // in asks whether a value is a member
    WriteLn('can reinflate');
  if not (ChainTool in Kit) then
    WriteLn('no chain repairs');
end.

How it works

1. TKit = set of TTool; builds a set type over the enumeration above it.
2. Include(Kit, Pump) adds a value, Exclude(Kit, Patch) drops one, + unions two sets.
3. if Pump in Kit then and not (ChainTool in Kit) decide what gets printed.

Keywords and builtins used here

• Exclude
• Include
• WriteLn
• begin
• end
• if
• in
• not
• of
• program
• set
• then
• type
• var

The run, in numbers

Lines

16

Characters to type

520

Tokens

95

Three-star pace

70 tpm

At the three-star pace of 70 tokens a minute, this run takes about 81 seconds.

Type this snippet

Step 2 of 3 in Enums & sets, step 17 of 27 in Language basics.

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Sets in other languages

• Java
• Scala
• Swift