diff --git a/3_Advanced_Data_Types.ipynb b/3_Advanced_Data_Types.ipynb
index bb61f351c2d59a9bcc28a3dfd14bedccae1efebd..8ce0a004709e0bf6864d8b3338e68b70098dbe48 100644
--- a/3_Advanced_Data_Types.ipynb
+++ b/3_Advanced_Data_Types.ipynb
@@ -631,7 +631,7 @@
"id": "647530cd-480a-414f-a8ec-1375e05a9e1b",
"metadata": {},
"source": [
- "## Structs"
+ "## Objects and structs"
]
},
{
@@ -814,10 +814,10 @@
"metadata": {},
"outputs": [],
"source": [
- "function printpoint(p)\n",
+ "function print_point(p)\n",
" println(\"($(p.x), $(p.y))\")\n",
"end\n",
- "printpoint(p)"
+ "print_point(p)"
]
},
{
@@ -827,13 +827,13 @@
"metadata": {},
"outputs": [],
"source": [
- "function printbook(book)\n",
+ "function print_book(book)\n",
" println(\"Title: $(book.title)\")\n",
" println(\"Author: $(book.author)\")\n",
" available = book.properties[\"available\"]\n",
" println(\"Available: $(available)\")\n",
"end\n",
- "printbook(book)"
+ "print_book(book)"
]
},
{
@@ -889,8 +889,16 @@
"source": [
"### References and values\n",
"\n",
- "Each object (instance of a struct) is stored at some memory address. The operator `===` checks if two variables point to the same memory address of the object. For example\n",
- "\n",
+ "Each object (instance of a struct) is stored at some memory address. The operator `===` checks if two variables point to the same memory address of the object. For example"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "ed713d91-17f4-4010-a7d3-d39826cffc97",
+ "metadata": {},
+ "outputs": [],
+ "source": [
"book_copy = book\n",
"@show book_copy === book;"
]
@@ -950,17 +958,174 @@
"metadata": {},
"outputs": [],
"source": [
- "import Core\n",
+ "import Base: ==\n",
"\n",
"function ==(book1::Book, book2::Book)\n",
" return book1.title == book2.title && book1.author == book2.author\n",
- "end"
+ "end\n",
+ "\n",
+ "@show book_copy == book;\n",
+ "@show book_copy === book;"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "87c1e4fb-d4e2-4ada-a97f-61273012146c",
+ "metadata": {},
+ "source": [
+ "With this we can compare if two books are the same, even if they are two distinct instances of the same struct."
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "9263a1ae-52ee-4afc-9d9f-0f1341b64bc0",
+ "metadata": {},
+ "source": [
+ "## Pure and impure functions"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "f638e9b3-9926-46fc-81e0-d49c877a3bbb",
+ "metadata": {},
+ "source": [
+ "We have seen that it is quite convenient to pass objects to functions. So far we have seen functions that print the content or that create a new object. None of these functions are modifying the content of the input objects.\n",
+ " - A function that does not modify the input it is also said **pure**.\n",
+ " - A function which modifies the input it is said **impure**. In Julia impure functions are highlighted by adding a `!` as the last character of the name.\n",
+ "\n",
+ "Let's consider a modified version of the book for an example."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "7f892e07-a601-4cba-b58d-40be9c8e93ab",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "book = Book(\"Der Hobbit\", \"J.R.R. Tolkien\", Dict(\"available\" => true, \"copies_in_stock\" => 10))\n",
+ "@show book;"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "99f4d6c9-2633-4394-b6a0-e0ce0c05e0db",
+ "metadata": {},
+ "source": [
+ "Then we could think of a function which updates the database whenever we order new copies."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "04937488-a556-44ad-97be-98b017f293fd",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "function order_book!(book, number_of_copies)\n",
+ " if number_of_copies <= 0\n",
+ " return\n",
+ " end\n",
+ " book.properties[\"copies_in_stock\"] += number_of_copies\n",
+ " book.properties[\"available\"] = true\n",
+ "end\n",
+ "\n",
+ "order_book!(book, 5)\n",
+ "@show book;"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "93bc2e46-8530-4d1e-b7fa-55a74d1831c8",
+ "metadata": {},
+ "source": [
+ "## Exercise"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "b30bd560-5ff3-4706-9f53-e6a5158651e9",
+ "metadata": {},
+ "source": [
+ "Write an inpure function `sell_book!` for updating the book object whenever we sell a single copy. The function should complain if there are no copies available."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "6e79fe95-767d-4b3e-af58-623db6dc0712",
+ "metadata": {},
+ "outputs": [],
+ "source": []
+ },
+ {
+ "cell_type": "markdown",
+ "id": "5ed4d4e0-0454-4298-9a56-8fb32634aa24",
+ "metadata": {},
+ "source": [
+ "## Further exercises"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "8446f1db-d40f-4311-9597-3b3b4d913151",
+ "metadata": {},
+ "source": [
+ "- Create a time struct which stores the time of the day (hour, minute and second). Write a function which takes as input the time object and prints it. Then write a function which sums together two time objects and returns a new time object. If the total is more than 24 hours, it should reset as if it was the next day."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "5335e035-62ee-4d0f-acfc-a9e24ac26d99",
+ "metadata": {},
+ "outputs": [],
+ "source": []
+ },
+ {
+ "cell_type": "markdown",
+ "id": "32844b6f-518a-4174-83c6-0d7ebeabe4e4",
+ "metadata": {},
+ "source": [
+ " - Create a custom version of the `==` function which checks if two time objects are the same."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "966d4db1-c95a-4531-8209-a869519599ea",
+ "metadata": {},
+ "outputs": [],
+ "source": []
+ },
+ {
+ "cell_type": "markdown",
+ "id": "baa7e06f-e183-4ee7-912a-e22255e18e21",
+ "metadata": {},
+ "source": [
+ " - Create a custom version of the `<` and `<=` functions for time objects."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "c9b76667-731b-4ec2-aaf4-e94496f65b1a",
+ "metadata": {},
+ "outputs": [],
+ "source": []
+ },
+ {
+ "cell_type": "markdown",
+ "id": "1bdbd748-7482-4f54-99a7-3d6e74b65575",
+ "metadata": {},
+ "source": [
+ " - Create a custom version of the `<` and `<=` functions for time objects."
]
},
{
"cell_type": "code",
"execution_count": null,
- "id": "03594f56-48ee-4152-a42f-8e3588c3ab2e",
+ "id": "7df56050-686e-4a87-aa86-9b7f61315aa2",
"metadata": {},
"outputs": [],
"source": []