Property and Index Access

Jyro provides dot notation and bracket notation for accessing properties and elements on objects, arrays, and strings.

Dot notation

Access object properties by name:

obj.name                 # Property access
obj.address.city         # Nested property traversal

Bracket notation

Access array elements by index (zero-based), object properties by key, or string characters by position:

arr[0]                   # Array element (first)
obj["key"]               # Object property (for dynamic keys)
str[0]                   # String character (returns single-char string)

Bracket notation supports dynamic keys via expressions:

var field = "name"
var value = obj[field]   # Equivalent to obj.name

Null behaviour

Property access on an object returns null if the property does not exist
Index access returns null if the index is out of bounds or the key is missing
Accessing a property on null returns null (null propagation)
Assigning a property on null causes a runtime error (JM5306)

# Null propagates through chained access
var result = Data.user.profile.name   # null if any part of the chain is null

# Use null coalescing for defaults
var name = Data.user.name ?? "Unknown"

Assignment

Properties and indexes are assignable:

obj.name = "Bob"
arr[0] = 99
obj["dynamicKey"] = "value"

Deleting properties

The delete keyword removes a property from an object entirely - the key is gone, not just set to null.

Data.user = {name: "alice", password: "secret", role: "admin"}

delete Data.user.password           # Property is completely removed
# Data.user is now {name: "alice", role: "admin"}

# Dynamic key via bracket access
var field = "role"
delete Data.user[field]             # Removes "role" from Data.user

Rules:

delete only works on property access (obj.key) and bracket access (obj["key"])
delete on a non-existent property is a no-op (no error)
delete on a bare variable (delete myVar) is a compile-time error - variables cannot be deleted
delete Data is a compile-time error - Data itself cannot be removed
The target expression must be on the same line as delete

This is the only way to completely remove a key from the Data context. Setting a property to null leaves the key present in the output; delete removes it entirely.

Keywords as property names

Keywords are valid as property names when accessed via dot notation or bracket notation. This only applies to member access on objects - it does not allow keywords as local variable names.

Data.for = "loop data"         # Valid
Data.number = 42               # Valid
Data.string = "text"           # Valid
var value = Data["default"]    # Valid

# var for = "x"                # INVALID - syntax error