Biz is a bizarre programming language based on JoJo's Bizarre Adventure. I followed the guide Write Yourself a Scheme in 48 Hours as a starting point. It's interpreted and written in Haskell.
Do you have a suggestion for a new construct? Do you think something should be changed? Feel free to open an issue.
Build with stack and run like this.
stack run "filename.bz"
stack run
If you don't specify a file, the REPL will be launched. It isn't ready (like the language), but it could be hepful.
Sometimes, it's useful to keep track of important values or giving them a more interensting name. How can we do it? With the kono <name> <value> da expression.
kono diego 4 da means: binds the value 4 to the name diego and give back the value 4. From now on, we can refer to the name diego instead of using directly the value 4. We can update the value bond to the name diego in the same way: kono diego 6 da.
Consider the following code
kono a 1 da
kono b a da
kono b 2 da
When we use the kono...da expression, we make a copy of the value. Consequently, a is still 1, while b is updated to 2. The type of the value isn't important. We can update the value bond to a name for different types:
kono iggy 1 da
kono iggy "coffee" da
This means: bind the value 1 to the name iggy and update it with the value "coffee". From now on, we can use the name iggy instead of using the value "coffee" directly. It isn't important if we update the value bound to the name iggy with a value of a different type.
A name can be reliable, that is, its value can't be updated. Trying to update its value will give you an error
kono myVar yesyesyes da
kono reliable myVar da
kono myVar 4 da speedwagon error
The purpose of comments is to add notes about your code or to avoid executing the beautiful code you have just written. Everything in the comments is ignored. A comment begins with the word speedwagon and ends with a newline
speedwagon He's Immortal! Unkillable! Unmatched!
kono Kars "ultimate lifeform" da
Why having multi-line comments when we can have multiple single-line comments?
speedwagon This is the first comment line
speedwagon and this is the second one
Some programming languages have things called boolean or the concept of "truthiness" for things that are true or false, black or white, 0 or 1. Biz has two expressions that accomplish this purpose: yes and no. They can be repeated more than one time: yesyesyes, nono, yesyesyesyesyes are valid expressions.
kono bool yes da
speedwagon bool holds the yes value
kono bool nonono da
speedwagon bool holds the no value
kono bool boingo yesyes and no
speedwagon bool hols no, the result of yesyes ∧ no
| Action | Result |
|---|---|
and |
yes if both values are yes, no otherwise |
or |
yes if at least one value is yes, no otherwise |
xand |
yes if both values are the same, no otherwise |
xor |
yes if only one value is yes, no otherwise |
equal |
yes if the values are the same, no otherwise |
There is only one action that takes only one Both value. It's opposite and it gives yes if the value is no, no otherwise.
Numbers are cool and they let us make amazing things. In Biz we can express numbers in two ways: with a point (pointless) or without a point (pointplus). Examples of pointless numbers are 0, 1, -1, 4. On the other hand, pointplus numbers could be the following: 0.1, -4.4, 123.444. You can manipulate pointless numbers and pointplus numbers with the following primordial binary actions (you can't mix pointless and pointplus numbers):
| Action | What it gives |
|---|---|
+ |
the sum |
- |
the difference |
* |
the product |
/ |
the quotient |
= |
yes if the numbers are equal, no otherwise |
/= |
yes if the numbers are not equal, no otherwise |
> |
yes if the first number is greater than the second one, no otherwise |
< |
yes if the first number is less than the second one, no otherwise |
>= |
yes if the first number is greater or equal than the second one, no otherwise |
<= |
yes if the first number is less or equal than the second one, no otherwise |
\ |
the remainder (only for pointless numbers) |
You can store text by enclosing it with the symbol ". The character \ is used to insert characters hard to type: \n, \t, \r, \\ , \". Emoji are supported. "I am Yoshikage Kira...", "a", "", "\\\r\\t", "🗿", are valid Text values.
| Action | What it gives |
|---|---|
++ |
adds to the end |
-- |
adds to the start |
It's possible to chain multiple actions by enclosing them between { and } and separating them with a newline. The sequence expression is useful when you want to evaluate multiple expresssions (e.g. the body of an action)
{
yes
123
no
}
The result of the evaluation of a sequence expression is the last expression in the list. The previous code evaluates to no. The empty sequence expression ({}) gives the value none
This expression let you do something based on a condition
will i hit you with my right fist or my left <condition>
right <yes_expression>
left <no_expression>
both <always_expression>
<condition> is the condition to be evaluated. If it is evaluated to yes, <yes_expression> will be evaluated. Otherwise, <no_expression> will be evaluated. <always_expression> will be always evaluated. left, right and both are optional. If none of them is provided, the whole expression will be evaluated to none. It is possible to use which fist instead of will i hit you with my right fist or my left.
which fist yes
is a valid expression.
Actions are blocks of code that can take some input values (parameters) and can give a result. The action in the example below is called multiply, it takes two parameters (that should be numbers) and it multipies them, giving us the product:
oingo multiply x y :
boingo x * y
oingo is used to create an action, while boingo is used to call an action.
If you want to summon an action, the expression boingo <action> (<params>). <action> is the name of the action we want to call (e.g. +, and, etc.), <params> is a comma separated list of parameters you want to feed to the action.
oingo + 1 2 :
oingo and yes no
In case of a binary action (an action that takes exactly two parameters), we can call it with the syntax boingo <param1> <action> <param2>.
oingo 1 + 2
oingo yes and no
We can't update the value bond to a name outside the action within the action. Consider the following example:
kono name "value" da
boingo action : : kono name "new value" da
speedwagon error
In order to be able to update it, we must add the attribute no dignity (or nodignity) to the name.
kono no dignity name "value" da
boingo action : kono name "new value" da
speedwagon "new value" is bound to name
It is possible creating an action and immediately calling it
oingo boingo greet name : oingo echoes name : "hol horse" :
Let's split it:
boingo greet name : oingo echoes name :creates and gives an action calledgreetthat takes one parameter calledname. Its body consists of calling the actionechoeswith thenameas its argument.oingo ... "hol horse" :calls the action just created with `"hol horse" as its argument.
If we don't want to create the action but just using it one time, we can replace the action name with combo
oingo boingo combo name : oingo echoes name jo "hol horse" jo
An handy construct for storing values is the doppio one. It is possible to store any amount of values of any type.
speedwagon the empty doppio
doppio
speedwagon a doppio with three elements
dop 1 "bossu" nonono pio
The dururu construct let us take the ruth element from the start. In other words, with duru we take the first item, with dururu the second one, and so on. rurudu works in the same way, but it takes the ruth element from the end.
speedwagon takes the 4th element from the start (the second "a")
dururururu dop "a" "b" "b" "a" "c" "c" "h" "i" "o" pio
speedwagon takes the 4th element from the end (the second "c")
rurururudu dop "a" "b" "b" "a" "c" "c" "h" "i" "o" pio
Another important construct is moshimoshi. Used with dururu or rurudu, updates that particular element with a new value. It doesn't affect the original doppio.
kono gio dop "g" "i" "o" "v" "a" "n" "n" "a" pio da
dururururururururu moshimoshi "i" gio
speedwagon gio is dop "g" "i" "o" "v" "a" "n" "n" "i" pio
As our programs become bigger and complicated, we need to evaluate multiple expressions. This is the purpose of the sequence construct. Check the following example:
{}
This is the empty sequence and it's evaluated to none, a special value that can't be used. Let's see a more useless example:
{
kono unluckyNumber 4 da
oingo unluckyNumber * unluckyNumber
}
First, we introduce a name for the value 4, then, we multiply it for itself. The result of the expression is 16, the result of the last expression in the sequence. In more complex sequences, you often don't want to evaluate every single expression. Consider this snippet:
boingo fact number : {
will i hit you with my right fist or my left oingo = number 0 jo
right 1
left oingo * number oingo fact oingo - number 1 jojojo
}
This is the Biz rapresentation of the well-know factorial function. Everything works well for positive numbers, but what happens with negative numbers? The recursion doesn't have a base case and we get stuck. We can exit immediatly if the number provided is negative in order to the make the action a little more safe.
boingo aLittleMoreSafeFact number : {
which fist oingo < number 0 :
right arrivederci -1
will i hit you with my right fist or my left oingo = number 0 jo
right 1
left oingo * number oingo fact oingo - number 1 jojojo
}
The action aLittleMoreSafeFact works like fact, but we get the value -1 when we call it with a negative number. When we encounter arrivederci, its expression is evaluated and its result is the result of the whole sequence.Consequently, the expressions after arrivederci aren't evaluated.
There is another way to write the arrivederci expression:
[ari]*arri <expression> vederci
Any amount of ari, followed by arri, the expression and vederci
boingo goodbye name :
ariariariariarri oingo ++ "Arrivederci " name : vederci
speedwagon "Arrivederci Pesci"
One of the most common things in programming is doing the same thing over and over. Do you know how Gold Experience Requiem works? There are 3 kinds of loops.
The infinite loop doesn't have an exit condition and it's written in the form goldexperiencerequiem <expression> (or justger <expression>).
`goldexperiencerequiem` oingo echoes "wha-" jo
This line of code keeps printing the text "wha-" indefinitely. what if we want to exit the loop after just one iteration?
ger {
oingo echoes "wha-" jo
arrivederci
}
speedwagon prints "wha-"
In other words, we have a sequence of expressions (delimited by the characters { and }) which contains an action call and the arrivederci expression.
The range loop has the form gold <localName> <startingValue> experience <increment> requiem <condition> <body>. Check the following example:
gold sexPistol 1 experience 1 requiem oingo < sexPistol 8 jo
oingo echoes oingo ++ "Sex Pistol number " sexPistol jojo
speedwagon prints "Sex Pistol number 1"...
The starting value is 1 and it can be retrieved with the sexPistolName;1 is the increment, that is, the value it will be added to the starting value; oingo < sexPistol 8 jo is the keep-looping codition: if it's yes we keep looping, if not, we exit the loop; finally we have the body which prints a line. Going back to our example, Sex Pistol number 4 doesn't exist, so we can avoid printing it:
gold sexPistol 1 experience 1 requiem oingo < sexPistol 8 jo {
which fist oingo = sexPistol 4 jo
right king crimson
oingo echoes oingo ++ "Sex Pistol number " sexPistol jojo
}
king crimson (or emperor crimson) skips the current loop iteration, forcing the evaluation to the next one.
Range loop are handy, but not so handy while working with doppio. Let's try to recreate the previous example using doppio to store all the Sex Pistols values:
kono sexPistols dop 1 2 3 5 6 7 pio da
gold sexPistol 1 experience 1 requiem oingo < sexPistol 7 jo {
oingo echoes oingo ++ "Sex Pistol number " duru sexPistols jojo
kono sexPistols oingo beep sexPistols jo da
}
We fetch the first element of sexPistols and we print it. Then, we create an new doppio without the first element (beep action) and we bind it to to sexPistols. Let's see the same code expressed with the doppio loop:
ger sexPistol dop 1 2 3 5 6 7 pio
oingo echoes oingo ++ "Sex Pistol number " sexPistol jojo
doppio is useful when you want to store values in a specific order. Stands are used to store values without any order and with a specifi name. Let's see how everything works:
speedwagon we create a new user called Jotaro
user Jotaro
speedwagon we create a new stand called StarPlatinum
stand StarPlatinum
speedwagon now Jotaro has the StarPlatinum stand
(StarPlatinum -> Jotaro)
speedwagon we create a new stand called TheWorld and we give it two abilities
stand TheWorld : ability stopTime 1; ability mudamuda "oh-oh" :
speedwagon we give TheWorld to Jotaro
(TheWorld -> Jotaro)
speedwagon we give an ability to Jotaro's StarPlatinum
speedwagon StarPlatinum itself isn't updated
((ability starFinger "oraoraora") -> StarPlatinum -> Jotaro)
We create users, we create stands, we give stands some abilities and we give users some stands using the -> (arrow) operator. There is <- (backward arrow) operator: it works in the same way, but in the opposite direction:
(user Okuyasu) <- (stand ZaHando) <- (ability deleteSpace 1)
We can retrieve stands and abilities using the ! (cry) operator:
Okuyasu!!!ZaHando!deleteSpace!!!!!
There is no limit to the amount of !
The power of moodyblues is to repeat things already done. Let's see how it works:
{
oingo echoes "first" jo
oingo echoes "second" jo
oingo echoes "third" jo
moody blues 2
oingo echoes "fourth" jo
}
This code will print:
"first"
"second"
"third"
"second"
"third"
moody blues <number> moves the execution back of <number> expressions and it will get ignored the next time it will be encoutered. Don't worry if <number> is greater then the number of avaible expressions. The execution will wrap around from the end of the sequence
{
oingo echoes "first" jo
oingo echoes "second" jo
oingo echoes "third" jo
moody blues 9
oingo echoes "fourth" jo
}
The output is:
"first"
"second"
"third"
"third"
"fourth"
For a better learning experience, listen to this.
During the execution of a Biz program, we bind many values ​​with as many names. Killer queen introduces a way to have multiple snapshots of the bindings. An example will make it clear.
kono hayato "perv kid" da
killer queen hand
The second line creates a snapshot of all the current bindings, hayato included. Now, if we update hayato with a new value or we introduce new bindings, the bindings in the snapshot aren't updated.
kono another 3 da
bites the dust hand
The first line creates a new binding, but the second line loads the snapshot called hand overrinding all the current bindings, another included. Trying to get value bond to another wil lresult in an error. It is possible having multiple snapshots at the same time:
kono hayato "smart kid" da
killer queen strayCat
kono coolCat "nice song" da
killer queen hotSpace
bites za dusto strayCat
The mista contruct is used to check if an expressions evaluates to something related to the number four
Splitting code in multiple files is the way to go if you want to become a successful Biz programmer. This is accomplished with parts. Every part must be defined in a file with the same name. For example, the part StardustCrusaders is defined in a file named StardustCrusaders.bz. It is possible to put parts in subdirectories. The part Stardust.Crusaders must be in a directory called Stardust which has a file named Crusaders.bz. The first expression of each file must be part <part_name>. For example:
part Narancia
This line says: "from now on, everything belongs to the Narancia part. That is, you can call bindings specifying the part they belong to (it isn't mandatory):
kono firstFactor 16 da
kono secondFactor 55 da
kono product oingo * Narancia.firstFactor Narancia.secondFactor jo da
speedwagon product isn't 28
We can bring other parts to our part. Let's say we have another part called Stardust.Crusaders
part Stardust.Crusaders
kono silverTwist "nice song!" da
kono product 28 da
We can add it to our part like this:
part Narancia
skip part Stardust.Crusaders
oingo echoes silverTwist jo
oingo echoes StardustCrusaders.product jo
speedwagon prints 28
We aren't forced to use the namepart. We can skip the part with a new name:
part Narancia
skip part Stardust.Crusaders as ShitpostCrusaders
oingo echoes silverTwist jo
oingo echoes ShitpostCrusaders.product jo
speedwagon prints 28
- mista
- so it's the same stand as ...
- this is a test
- repl