Symbols - Soli MVC Documentation

Creating Symbols

# Symbol literals start with a colon
let s = :name
let status = :active

# Symbols can contain letters, numbers, underscores
let field = :first_name
let key = :user_id

# Symbols can end with ? or !
let check = :empty?
let action = :save!

Equality & Comparison

Symbol Equality

Symbols with the same name are equal. Symbols are not equal to strings, even with the same text.

# Same symbols are equal
:name == :name    # true
:foo == :foo      # true

# Different symbols are not equal
:name != :age     # true

# Symbols are NOT equal to strings
:name != "name"   # true
"name" != :name   # true

As Hash Keys

Symbol Keys in Hashes

Symbols make great hash keys. They are distinct from string keys in the same hash.

# Symbol keys use fat arrow syntax
let person = { :name => "Alice", :age => 30 }
person[:name]   # "Alice"

let config = { :host => "localhost", :port => 3000 }
config[:host]   # "localhost"

# Symbol keys are separate from string keys
let h = { :name => "sym_value" }
h["name"] = "str_value"
h[:name]     # "sym_value"
h["name"]    # "str_value"
h.length     # 2

Conversion Methods

.to_s / .to_string

Convert a symbol to its string representation (without the colon prefix).

:name.to_s       # "name"
:hello.to_string # "hello"

# Round-trip conversion
let original = "test"
let sym = original.to_sym
sym.to_s == original  # true

String.to_sym

Convert a string to a symbol.

"hello".to_sym       # :hello
"first_name".to_sym  # :first_name

Introspection Methods

.class

Returns the type name as a string.

:name.class   # "symbol"

.inspect

Returns a developer-friendly string representation with the colon prefix.

:name.inspect         # ":name"
:hello_world.inspect  # ":hello_world"
:empty?.inspect       # ":empty?"

.nil? / .blank? / .present?

Symbols are always truthy and present.

:name.nil?      # false
:name.blank?    # false
:name.present?  # true

.is_a?(type_name)

Check if the value is of the given type.

:name.is_a?("symbol")   # true
:name.is_a?("object")   # true
:name.is_a?("string")   # false

&:method Shorthand

&:method

Use &:method_name as a shorthand for creating a lambda that calls a method on each element. Works with map, filter, and other collection methods.

# Convert all elements to strings
let arr = [1, 2, 3]
arr.map(&:to_s)       # ["1", "2", "3"]

# Filter with predicate methods
let nums = [1, 2, 3, 4, 5, 6]
nums.filter(&:even?)  # [2, 4, 6]

# Equivalent to writing a full lambda
arr.map(|x| x.to_s)  # same as arr.map(&:to_s)

Symbols in Expressions

Ternary & Conditionals

Symbols work naturally in ternary expressions and conditionals. They are always truthy.

# Ternary with symbols
let result = true ? :yes : :no
result  # :yes

# Symbols as status values
let status = user.active ? :active : :inactive