ch06

dz / grokking_simplicity / ch06

Summary

Grokking Simplicty Chapter 6: Staying immutable in a mutable language

Node Tree

• writes_data_mutable
• COW_discipline
• immutable_reads_calculations
  • mutable_reads_actions
  • convert_writes_reads
• nested_data_cow
  • only_parts
• operation
• read_and_write
  • shift
    • either_shift_refactor
      • split_up_into_2
      • return_2_values
• shallow_copy
• structural_sharing

Nodes

operation
content	Operation can be categorized as a read or write

COW_discipline
content	Copy-on-write discipline: make copy, modify copy, return copy

read_and_write
content	What about a function that does both a read and write?
children	shift (example of function that does both read/write)

shift
content	Example: shift function. Returns first value, shifts array function
children	either_shift_refactor
parents	read_and_write

either_shift_refactor
content	Either
children	split_up_into_2, return_2_values
parents	shift

split_up_into_2
content	Split up into 2 functions
parents	either_shift_refactor

return_2_values
content	Return 2 values from function
parents	either_shift_refactor

immutable_reads_calculations
content	Reads to immutable data structures are calculations
children	mutable_reads_actions (Corollary), convert_writes_reads

mutable_reads_actions
content	Mutable reads are actions
parents	immutable_reads_calculations

writes_data_mutable
content	Writes make data mutable

convert_writes_reads
content	converting writes to reads makes more calculations
parents	immutable_reads_calculations
remarks	I'd like to understand this better. examples are in the book fortunately.

shallow_copy
content	Shallow Copy: only duplicate top-level structure of nested data

structural_sharing
content	Structural Sharing: two pieces of data shrae some of their references

nested_data_cow
content	Nested data and copy-on-write make efficient use of references
children	only_parts

only_parts
content	only parts of structure need to be replaced
parents	nested_data_cow