various docs cleanup
This commit is contained in:
Peli de Halleux
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# Assignment Operator
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Set the value for local and global variables.
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### @parent js/operators
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Set or change the value of a variable
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### Block Editor
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### Touch Develop
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Use the assignment operator (:=) to set or change the value of a [local variable](/blocks/variables/var) or a [global variable](/js/data).
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### Declare a variable
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Declare a new *local* variable using the [var](/blocks/variables/var) statement and the assignment operator (`:=`). Like this:
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```blocks
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let num1 = 7
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let name = "Joe"
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```
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The variable's name is on the left of the assignment operator (`:=`) and the variable's value is on the right:
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*variable name* `:=` *value*
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See [global variable](/js/data) for info on declaring a global variable.
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### Change a variable
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After a global or local variable is defined, use the assignment operator (`:=`) to change the variable's value.
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```
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g = 42
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num1 = 42
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```
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### Notes
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* Don't confuse the assignment operator `:=` with the equality operator `=`, which is used to compare values.
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* You can use the assignment operator `:=` with variables of each of the supported [types](/js/types).
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### See also
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[local variables](/reference/variables/var), [global variables](/js/data), [types](/js/types)
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# Boolean
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true or false.
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### @parent js/language
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A Boolean has one of two possible values: `true`; `false`. Boolean (logical) operators (*and*, *or*, *not*) take Boolean inputs and yields a Boolean value. Comparison operators on other types ([numbers](/reference/types/number), [strings](/reference/types/string)) yields a Boolean value.
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### Block Editor
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In the Block Editor, the following blocks represent the true and false Boolean values, which can be plugged in anywhere a Boolean value is expected:
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The next three blocks represent the three Boolean (logic) operators:
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The next six blocks represent comparison operators that yield a Boolean value. Most comparisons you will do involve [numbers](/reference/types/number):
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### Touch Develop
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### ~hide
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```
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let condition = true
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let condition2 = true
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```
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### ~
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Boolean values and operators are often used with an [if](/blocks/logic/if) or [while](/js/while) statement to determine which code will execute next. For example:
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```
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if (condition && condition2) {
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// This code runs if both `condition` and `condition2` are `true`
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} else {
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// This code runs if either `condition` or `condition2` is `false`
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}
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```
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### Functions that return a Boolean
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Some functions return a Boolean value, which you can store in a Boolean variable. For example, the following code gets the on/off state of `point (1, 2)` and stores this in the Boolean variable named `on`. Then the code clears the screen if `on` is `true`:
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```
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let on = led.point(1, 2)
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if (on) {
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basic.clearScreen()
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}
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```
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### Boolean operators
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Boolean operators take Boolean inputs and evaluate to a Boolean output:
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### Conjunction: `A and B`
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`A and B` evaluates to `true` if-and-only-if both A and B are true:
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- `false and false` = `false`
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- `false and true` = `false`
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- `true and false` = `false`
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- `true and true` = `true`
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### Disjunction: `A or B`
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`A or B` evaluates to `true` if-and-only-if either A is true or B is true:
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- `false or false` = `false`
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- `false or true` = `true`
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- `true or false` = `true`
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- `true or true` = `true`
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### Negation: `not A`
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`not A` evaluates to the opposite (negation) of A:
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* `not false` = `true`
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* `not true` = `false`
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### Example
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This example turns on LED `3 , 3`, if LEDs `1 , 1` and `2 , 2` are both on:
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```
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if (led.point(1, 1) && led.point(2, 2)) {
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led.plot(3, 3)
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}
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```
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### Comparisons of numbers and strings
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When you compare two Numbers, you get a Boolean value, such as the comparison `x < 5` in the code below:
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```
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let x = Math.random(10)
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if (x < 5) {
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basic.showString("Low", 150)
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} else {
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basic.showString("High", 150)
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}
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```
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See the documentation on [Numbers](/reference/types/number) for more information on comparing two Numbers. You can also [compare strings](/reference/types/string-functions) using the `equals` function.
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### See also
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[if](/reference/logic/if), [while](/js/while), [number](/reference/types/number)
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# Global Variables
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How to define and use global variables.
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### @parent js/language
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A variable is a place where you can store data so that you can use it later in your code. A *global* variable is accessible from every point in your code.
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### Block Editor
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In the Block Editor, all variables are global. See [Block Editor](/blocks/editor) for info on creating global variables in a Block Editor script. The following block is used to set (assign) global variable's value:
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The block below retrieves (gets) the current value of a global variable:
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### Touch Develop
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In Touch Develop variables are either [global](/js/data) or [local](/reference/variables/var). Variables have a name, a [type](/js/types), and value:
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* the *name* is how you'll refer to the variable
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* the *type* refers to the kind of value a variable can store
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* the *value* refers to what's stored in the variable
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[Global variables](/js/data) are variables that are available throughout your script. Unlike [local variables](/reference/variables/var), global variables are accessible across functions and in nested code blocks.
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### Create a global variable
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To create a new global variable:
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1. In the Touch Develop [editor](/js/editor), click `script` (to the right of the search box).
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2. Click `+` **add new**.
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3. Click `data->` **data** and then choose a [type](/js/types).
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4. Enter a name for your global variable and click **OK**.
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### Set and use a global variable
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To use a global variable that you've declared (using steps above):
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1. In the Touch Develop [editor](/js/editor), click `data-> ` **data** or `data->` + *variable name*.
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2. Click `:=` (assignment).
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2. Click on the right-side of `:=` and type or click what you want to store in the variable.
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Your code should look something like this:
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// global number variable
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```
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counter = 2
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```
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// global string variable
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```
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name2 = "Mike"
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```
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// global boolean variable
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```
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bool = true
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```
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(for info on creating image variables, see [Image](/reference/image/image))
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Once you've defined a variable and set it's initial value, use the variable's name whenever you need what's stored in the variable. For example, the following code gets the value stored in the global `counter` variable and shows it on the screen:
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```
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basic.showNumber(counter, 100)
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```
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To change the contents of a variable use the [assignment operator](/reference/variables/assign) `:=`. The following code increments `counter` by 10:
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```
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counter = counter + 10
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```
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### Promote, demote, and extract
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To **promote** a local variable to a global variable:
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* select the local variable name and click `promote to data`. The [var](/reference/variables/var) keyword changes to the data symbol `data->`.
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To **demote** a global variable to a local variable:
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* select the global variable name and click `demote to var`
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To **extract** the content of a global variable to a local variable:
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* select the global variable name and click `extract to var`
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### See your global variables
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To see a list of the global variables in your script:
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* click `script` (along the top) and scroll down to the **vars** heading
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### Lessons
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[counter](/lessons/counter), [rotation animation](/lessons/rotation-animation), [digital pet](/lessons/digital-pet), [offset image](/lessons/offset-image)
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### See also
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[local variables](/reference/variables/var), [types](/js/types), [assignment operator](/reference/variables/assign)
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@ -1,112 +0,0 @@
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# Touch Develop Editor
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The Touch Develop editor.
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### @parent js/contents
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The Touch Develop editor is where you write and test your code. If you're new to Touch Develop, check out the [Touch Develop editor video](/getting-started/touchdevelop-editor).
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To create a new Touch Develop script:
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1. Go to the micro:bit website and click **Create Code** (along the top).
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2. Under the Touch Develop editor heading, click **New project**.
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3. Type a name for your script and click **create**.
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An empty script with a [function](/js/function) called `main` is created.
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## The Editor Menu Bar
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The Touch Develop editor has a bar of options above the code area:
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* `my scripts` takes you back to a list of your scripts (My Scripts). The open script is automatically saved (in the cloud) when you leave the editor.
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* `run` executes your script, showing you the results on the on-screen micro:bit device. See [run scripts in the browser](/js/simulator) for more about this.
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* `compile` sends your script to an ARM compiler, which creates a file that you can run on your micro:bit. See [run scripts on your micro:bit](/device/usb) for more info.
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* `undo` undoes changes that you made to your script.
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* `search code...` search for functions in libraries such as the micro:bit library.
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* `script` opens script options, where you can do things like publish and preview. See **script options** below.
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Many of the above buttons aren't much use until you've written some code, so let's move on to the Code Keyboard.
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## Code Keyboard
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The Code Keyboard makes it easy to write code on a touch screen device or by using your mouse. You can also type code using your computer keyboard if you know what function or statement you want (see [Touch Develop documentation](/js/contents) for a complete list).
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To open the Code Keyboard, click on a line of code:
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An on-screen keyboard appears, with buttons that vary depending on what's selected.
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### Statements
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The first row of the Code Keyboard has Touch Develop [statements](/js/statements) that you can insert into your code. These buttons are blue and include things like [var](/reference/variables/var), [if](/reference/logic/if), [for](/reference/loops/for) , and [while](/js/while). Click `more` to see additional statements.
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### The BBC micro:bit, math, and code buttons
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* `micro:bit`: click to see all the [micro:bit functions](/js/contents); click `more` to scroll left to right. The micro:bit functions are also grouped together behind the following category buttons: `basic`, `control`, `input`, `image`, `led`, and`pins`
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* `code`: click to access functions you've written (see [call a function](/js/call) for more info)
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* `math`: click to see [math functions](/js/math); such as `abs` and `round`
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* `bits`: click to see functions for bit-level manipulation of integers
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### Editing code: add, copy, paste, and cut
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In the coding area...
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* **add**: to add a new line, click on a line and then click a **+** to add a new line above or below the current line
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* **copy, paste, cut**: click on a line then click **copy** or **cut**. Then click on a new line, and click **paste**.
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### Block editing
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To copy, cut, or comment out a block of code (more than one line):
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1. Click on a line of code.
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2. Press and hold the `Shift` key, and then press the `Up arrow` or `Down arrow` key on your keyboard (this selects multiple lines).
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3. Choose a block editing option like copy, cut, or [comment out](/js/comment).
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### Script options
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Click `script` (in the upper-right corner) to open the script options:
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Here you'll find options like...
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* `script properties`: the script name, description, and whether or not the script is a library (more info below)
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* `publish`: share a script with other users by [publishing](/js/publishing) it
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* `share`: share a link to a published script (see [publish as script](/js/publishing) for more info)
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* `preview`: preview a documentation script
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* `+` `add new`: add a new [function](/js/function), [global variable](/js/data), picture, or library to a script
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* *code*: the functions in your script; click a function to open it in the editor
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* *global vars*: the [global variables](/js/data) in your script; click a variable to go to that variable
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* *libraries*: the libraries added to your script
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* *art*: picture and video resources added to your script
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### Script properties
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To edit a script's properties, click `script` (in the upper-right corner), and then click the script name or script properties.
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* `name`: the script's name (60 character limit)
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* `description`: a description of what your script does along with #hashtags for search (for example, #game or #maker). Hashtags are especially important if you publish your script (200 character limit).
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* `this script is a library`: click this check box to turn a script into a library
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### Comments
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Comments are notes within your scripts. To learn how to insert comments into your scripts, see [Comments](/js/comment). You can format your comments using [markdown syntax](/js/markdown).
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### Share your scripts
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Share your scripts with other people by publishing them. See [publish a script](/js/publishing) for more info.
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### See also
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[publish a script](/js/publishing), [Touch Develop documentation](/js/contents)
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@ -9,8 +9,6 @@ Repeat code a fixed number of times.
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### Block Editor
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The Block Editor *for* loop is different than the Touch Develop *for* loop in an important way. The above for loop will iterate *five* times, with the loop variable *i* taking on values 0, 1, 2, 3, and 4. The Touch Develop for loop shown below will iterate four times:
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```
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@ -9,8 +9,6 @@ Conditionally run code depending on whether a [Boolean](/reference/types/boolean
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### Block Editor
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In the Block Editor, click on the dark blue gear icon (see above) to add an *else* or *if* to the current block.
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### Touch Develop
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@ -8,7 +8,6 @@ While you're writing and testing your scripts, you'll mostly be running scripts
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When you click `run main` in the Touch Develop editor, your code executes and the results are simulated on-screen, using an image of the BBC micro:bit device, like this:
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In the picture above, [plot image](/reference/led/plot-image) create a heart image that appears on the BBC micro:bit simulator.
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@ -17,7 +17,6 @@ let condition = false
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### Block Editor
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### Touch Develop
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Reference in New Issue
Block a user