tuple-nav-composition

Tuple Nav Composition

Core Concept

Navigation through product structures (tuples, named tuples, records) where multiple fields must be accessed and composed in parallel.

A TupleNav is a bundled Navigator that operates on all fields of a product simultaneously, maintaining structural integrity through composition.

Why Tuple Navigation?

Standard Specter navigators work on sequences (ALL, each element). But what about simultaneous access to multiple fields?

# Without TupleNav: Access fields separately, type mismatch risk
person = (name="Alice", age=30, email="[email protected]")

name_nav = @late_nav([INDEX(1)])     # But tuples aren't indexed this way!
age_nav = @late_nav([INDEX(2)])      # Fragile, error-prone

# With TupleNav: Access structurally, type-safe composition
record_nav = @tuple_nav([:name, :age])  # Access both fields as unit

Architecture

TupleNav Structure

struct TupleNav
    fields::Vector{Symbol}           # Field names to navigate
    navigators::Dict{Symbol, Navigator}  # Navigator for each field
    composition_strategy::Symbol      # :parallel, :sequential, :reduce
    output_type::Type                # (Field1Type, Field2Type, ...)
end

Product Types

Type	Navigation
(T1, T2, T3)	Positional tuple
NamedTuple{(:a, :b, :c)}	Named access
@NamedTuple{a::T1, b::T2}	Struct-like
Dict{K, V}	Key-based dictionary
Record/DataClass	Field-based

Composition Strategies

:parallel - Access all fields simultaneously

nav = @tuple_nav([:x, :y, :z], strategy=:parallel)
result = nav_select(nav, (x=1, y=2, z=3), id)
# => ((x=1), (y=2), (z=3))  # All accessed at once

:sequential - Access fields in order, threading results

nav = @tuple_nav([:x, :y, :z], strategy=:sequential)
# Field y receives result from x, z receives from y, etc.

:reduce - Fold/reduce across fields

nav = @tuple_nav([:x, :y, :z], strategy=:reduce)
# Combine results across fields: x + y + z