Lulu Enums — Stringification

Introduction

We provide several methods for converting Enum instances to strings.

Method	Brief Description
Enum:inline()	Returns a one-line string representation of self.
Enum:pretty()	Returns a “pretty” multiline string representation of self.
Enum:tostring(indent)	Returns a string representation of self with custom indentation.
Enum:__tostring()	A metamethod that connects Lua’s tostring and print functions to the Enum:inline method.

The methods show the enumerator names preceded by their ordinal values in square brackets. Associated data for the enumerators is also shown if present.

These methods play nicely with the scribe.putln formatted output functions in the Scribe module.

Enum:inline

This is the default method used by Lua’s print and friends. It is also used by the putln function when the format specifier is %t.

Example

local Suit = Enum{ 'Clubs', 'Diamonds', 'Hearts', 'Spades' }
print(Suit)

Output

Enum: [1] Clubs, [2] Diamonds, [3] Hearts, [4] Spades

Enum:pretty

This is a “pretty” multiline string representation of self. It is used by the putln function when the format specifier is %T.

Example

local Suit = Enum({
    Clubs    = { abbrev = 'C', color = 'black', icon = '♣', ordinal = 0 },
    Diamonds = { abbrev = 'D', color = 'red',   icon = '♦', ordinal = 1 },
    Hearts   = { abbrev = 'H', color = 'red',   icon = '♥', ordinal = 2 },
    Spades   = { abbrev = 'S', color = 'black', icon = '♠', ordinal = 3 }
})
1putln("%T", Suit)

1

The %T format specifier tells putln to use the Enum:pretty method to convert the Enum instance to a string.

Output

Enum:
    [0] Clubs = { abbrev = "C", color = "black", icon = "♣" },
    [1] Diamonds = { abbrev = "D", color = "red", icon = "♦" },
    [2] Hearts = { abbrev = "H", color = "red", icon = "♥" },
    [3] Spades = { abbrev = "S", color = "black", icon = "♠" }

Enum:tostring(indent)

This is a string representation of self with custom indentation. It is the workhorse method used by Enum:inline and Enum:pretty.

Example

print(Suit:tostring(' '))

Output

Enum:
  [0] Clubs = { abbrev = "C", color = "black", icon = "♣" },
  [1] Diamonds = { abbrev = "D", color = "red", icon = "♦" },
  [2] Hearts = { abbrev = "H", color = "red", icon = "♥" },
  [3] Spades = { abbrev = "S", color = "black", icon = "♠" }

See Also

Enum:mt