schemioscript

SchemioScript Language Skill

Overview

SchemioScript is a JavaScript-like scripting language designed for Schemio diagrams. It enables dynamic behavior, item manipulation, and complex interactions within diagram items.

Key Characteristics:

• JavaScript-like syntax with simplifications
• Dynamically typed
• Expression-oriented (last statement is return value)
• No explicit variable declaration keywords (except let for local scoping)
• Designed for diagram item scripting and templating

---

Basic Syntax

Variable Declaration

No const, let, or var keywords required. Simply assign a value:

name = "John"
age = 19
x = 4 + 5 * 4 + y

Multiple Statements

Separated by semicolon ; or newline:

x = 1; y = 2; z = x + y

// Or over multiple lines
a = 4 +
5 * 4 + y
% 3

Expression Return Value

Only the last statement in an expression is considered the return value:

// This returns 30
x = (a = 1; b = 2; a + b); x*10

---

Data Types

Primitives

• Number: 42, 3.14, -10
• String: 'hello', "world"
• Boolean: true, false
• Null: null

Complex Types

• Vector: 2D vector with x and y properties
• List: Ordered collection (similar to arrays)
• Map: Key-value pairs (hash table)
• Set: Collection of unique values
• Struct: Custom complex objects

---

Operators

Arithmetic

Comparison

Logical

Bitwise

Assignment

Increment/Decrement

Note: Pre-increment (++x) and post-increment (x++) are supported.

---

Control Structures

If Statements

If statements can be used as expressions and return the last executed statement:

x = 5
y = 3
result = 1

if (z == 0) {
    result = x + y
} else if (z == 1) {
    result = x * y
} else {
    result = x - y
}

As an expression:

x = getPosX()
x = if (x < 100) {
    step = 4
    x + step
} else { 0 }

While Loops

i = 0
sum = 0
while (i < 10) {
    sum += i
    i += 1
}

For Loops

C-like for loops:

for (i = 0; i < 5; i++) {
    log(i)
}

Multiple initializations:

for (i = 0, j = 10; i < j; i++, j--) {
    log(i, j)
}

---

Templated Strings

Use backticks to embed expressions in strings:

setTextColor('body', `rgba(${r + 10}, ${g}, 20, 0.5)`)

---

Item Referencing

Reference other diagram items using the @ symbol:

// Reference by name
pos = @Rect.getWorldPos()
@Rect.setWorldPos(pos.x + 20, pos.y - 10)

// Reference with special characters (use quotes)
pos = @"Rect 2".getWorldPos()
@"Rect 2".setWorldPos(pos.x + 20, pos.y - 10)

// Dynamic item referencing with templated strings
for (i = 1; i < 10; i++) {
    pos = @`Rect ${i}`.getWorldPos()
    @`Rect ${i}`.setWorldPos(pos.x + 20, pos.y - 10)
}

---

Vector Type

2D vector for geometric calculations:

Creating Vectors

v1 = Vector(3, 4)
v2 = Vector(1, -2)

Vector Properties

• x: X coordinate
• y: Y coordinate

Vector Operations

dx = v1.x - v2.x
dv = v1 - v2         // Vector subtraction
v3 = v1 + v2         // Vector addition
v4 = v1 * 10        // Scalar multiplication
v5 = v1 / 2         // Scalar division
v6 = 5 * v1         // Scalar on left side

Vector Functions

Examples

v = Vector(3, 5)
d = v.length()
normal = v.normalized()

v1 = Vector(1, 3)
v2 = Vector(4, 1)
p = v1.projection(v2)  // Scalar projection

v = Vector(2, 7)
v2 = v.rotate(PI() / 2)  // Rotate by 90 degrees

v = Vector(2, 7)
v_inv = v.inverse()  // Returns Vector(-2, -7)

---

List Type

Ordered collection similar to arrays:

Creating Lists

items = List(4, 5, 2)
emptyList = List()

List Functions

Examples

items = List('a', 'b', 'c')
items.add('d')
items.remove(1)  // Removes 'b'
item1 = items.get(0)  // 'a'

// Iteration
items.forEach((item, index) => {
    log(index, item)
})

// Mapping
numbers = List(1, 2, 3)
doubled = numbers.map((value, index) => { value * 2 })

// Filtering
filtered = numbers.filter((value) => { value > 1 })

// Find index
idx = items.findIndex((item) => { item == 'b' })

---

Map Type

Hash table for key-value pairs:

Creating Maps

m = Map('name', 'John', 'age', 30)
emptyMap = Map()

Map Functions

Examples

m = Map('name', 'John', 'age', 30)
log('Name:', m.get('name'))
m.set('age', 31)
m.has('name')  // true
m.delete('age')

m.forEach((value, key) => {
    log(key, value)
})

---

Set Type

Collection of unique values:

Creating Sets

s = Set('a', 'b', 'c', 'a')  // Duplicate 'a' is ignored
emptySet = Set()

Set Functions

Examples

s = Set('a', 'b', 'c')
s.add('d')
s.has('a')  // true
s.delete('b')

s.forEach((value) => {
    log(value)
})

---

Function Declaration

Named Functions (func keyword)

func minValues(a, b) {
    if (a < b) {
        a
    } else {
        b
    }
}
log(minValues(4, 1))  // 1

Arrow Functions

myFunc = () => {
    log('This is my function')
}

myMin = (a, b) => {
    if (a < b) {
        a
    } else {
        b
    }
}
log(myMin(4, 1))  // 1

Functions as Return Values

myMin = (a) => {
    (b) => {
        if (a < b) {a} else {b}
    }
}
log(myMin(4)(3))  // 3

Function Invocation

result = myFunc(arg1, arg2)

---

Local Variables

Use let keyword to create variables with function/loop/if scope:

name = 'John'

func someFunc() {
    let name  // Declares local variable
    name = 'Sara'
    log(name)  // 'Sara'
}

someFunc()
log(name)  // 'John' - outer variable unchanged

Shorthand declaration and assignment:

func someFunc() {
    let name = 'Sara'
    // ...
}

---

Structs

Custom complex object types:

Defining Structs

struct TreeNode {
    id: ''
    value: null
    parent: null
    childNodes: List()

    addNode(node) {
        this.childNodes.add(node)
        node.parent = this
    }
}

Simple field declarations (no defaults):

struct Point {x, y}

Creating Struct Instances

root = TreeNode('root')
child1 = TreeNode('child 1', 'custom value')
root.addNode(child1)

p1 = Point(0, 1)
p2 = Point(-3, 2)

Struct Features

• Fields are initialized with default values if not provided
• Methods can access struct instance via this keyword
• Constructor accepts arguments in order of field declarations

---

Built-in Functions

Math Functions

Examples

y = abs(-5)  // 5
x = pow(3, 2)  // 9
angle = PI() / 4  // 45 degrees in radians
random = rnd() * 10  // Random 0-10
value = round(3.78)  // 4

String & Text Functions

Color Functions

Color Object Methods:

• encode(): Encodes color to string
• gradient(anotherColor, t): Mix with another color (t = 0-1)

Examples

color = Color(255, 145, 140, 1.0)
encoded = color.encode()  // "rgba(255,145,140,1)"
color2 = Color(100, 0, 10, 1.0)
color3 = color.gradient(color2, 0.7)

color = decodeColor("rgba(255,240,200,1.0)")
log(color.r, color.g, color.b, color.a)

Utility Functions

Examples

id = uid()
result = ifcond(x > 10, -1, 1)  // -1 if x > 10, else 1

eventName = getEventName()
arg0 = getEventArg(0)

Type Conversion

---

Item Functions

Functions available in the context of diagram items. These functions operate on the current item unless specified otherwise.

Identification

Position & Transformation

Coordinate Conversion

Visibility

Mounting

Text Functions

Custom Variables

Examples

// Store and retrieve custom variables
setVar('srcX', getPosX())
setVar('dstX', -467*(slide - 1))

// Use in another function
setPosX(getVar('srcX') * (1 - t) + getVar('dstX') * t)

// Get with default
srcX = getVar('srcX', 0)
dstX = getVar('dstX')  // No default

Events

Finding Items

Item Manipulation

Examples

// Find and manipulate other items
it = findItemByName('ellipse')
dstX = it.getVar('dstX')
it.setPosX(dstX)
it.setTextSize('body', 30)

// Send custom events
sendEvent('my-custom-move', 'up', 10)

// Handle custom events
d = ifcond(getEventArg(0) == 'up', -1, ifcond(getEventArg(0) == 'down', 1, 0))
speed = getEventArg(1)
setPosY(getPosY() + speed * d)

// Duplicate items
newItem = duplicate('new_name')
newItem.setWorldPos(100, 0)

// Remove items
item = @Rect
item.remove()

// Add tags
rectItem = @Rect
rectItem.tag('new-tag')

---

Connector Functions

Additional functions for connector items:

Examples

connector = findItemByName('Connector 1')
n = connector.totalPoints()
p = connector.getPointWorldPos(1)
connector.setPointWorldPos(1, 45, -4)
pointIdx = connector.addWorldPoint(6, 1)
connector.removePoint(2)
length = connector.getLength()
p = connector.getWorldPosAtLength(56)

---

Path Functions

Functions for path items (similar to connectors but with multiple sub-paths):

Examples

pathItem = findItemByName('Path 1')
n = pathItem.totalPaths()
pointsNum = pathItem.totalPathPoints(0)
pathItem.closePath(0)
p = pathItem.getPathPointWorldPos(0, 4)
pathItem.setPathPointWorldPos(0, 4, 100, -54)
pathIdx = pathItem.addPath()
pathItem.addPoint(0, 5, 8)
pathItem.addBezierPoint(0, 5, 8, 2, 3, -1, -3)

---

Table Functions

Functions for table items:

---

Math Block Functions

Functions for math block items:

Note: Escape backslashes in TeX expressions:

mathBlock = findItemByName('Math 1')
mathBlock.setExpression('c = \\pm\\sqrt{a^{23} + b^{-12}}')

---

Value Functions

Functions available for modifying the "value" of the item, typically used by "textfield" shapes but could be used on any item.

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Reserved Keywords

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Operator Precedence

From highest to lowest:

1. ^ (power)
2. /, *, %
3. -, + (binary)
4. <<, >>
5. &
6. |
7. <, >, <=, >=
8. !=, ==
9. &&
10. ||
11. ++, --
12. -=, +=, *=
13. =

---

Implementation Details

Entry Point

• File: src/ui/templater/ast.js
• Function: parseExpression(expression)
• Returns: ASTNode

Tokenization

• File: src/ui/templater/tokenizer.js
• Function: tokenizeExpression(text)
• Token types: TERM, NUMBER, STRING, STRING_TEMPLATE, OPERATOR, RESERVED, etc.

AST Node Types

• ASTNode: Base class for all AST nodes
• ASTValue: Literal values (numbers, booleans, null)
• ASTVarRef: Variable reference
• ASTAssign: Assignment operation
• ASTMultiExpression: Multiple expressions (last is return value)
• ASTIFStatement: If statement
• ASTWhileStatement: While loop
• ASTForLoop: For loop
• ASTFunctionDeclaration: Function definition
• ASTFunctionInvocation: Function call
• ASTExternalObjectLookup: Item reference (@)
• ASTStringTemplate: Templated string
• ASTStructNode: Struct definition
• ASTLocalVariable: Local variable declaration

Execution Context

• Scope: Manages variable bindings and scope chains
• File: src/ui/templater/scope.js
• Supports nested scopes with parent references
• Provides external object lookup for @ references

Built-in Types Implementation

• Vector: src/ui/templater/vector.js
• List: src/ui/templater/list.js
• Color: src/ui/templater/color.js
• Map/Set: JavaScript built-ins wrapped in reservedFunctions

---

Common Patterns

Animation

// Linear interpolation
t = getEventArg(0)  // Assume t is 0-1
srcX = getVar('srcX', getPosX())
dstX = getVar('dstX', 100)
setPosX(srcX * (1 - t) + dstX * t)

Conditional Formatting

if (getValue() > 100) {
    setTextColor('body', 'rgba(255,0,0,1)')
} else {
    setTextColor('body', 'rgba(0,255,0,1)')
}

Looping Through Items

for (i = 1; i <= 10; i++) {
    item = findChildItemByName(`item-${i}`)
    if (item) {
        item.setPosX(i * 50)
    }
}

Using Vectors

pos = getWorldPos()
targetPos = @Target.getWorldPos()
direction = (targetPos - pos).normalized()
distance = pos.distance(targetPos)  // Note: Not built-in, would need custom implementation

Struct with Methods

struct Circle {
    x: 0
    y: 0
    radius: 10

    area() {
        PI() * this.radius * this.radius
    }

    circumference() {
        2 * PI() * this.radius
    }
}

c = Circle(5, 5, 20)
log(c.area())

---

Limitations

1. No native arrays (use List instead)
2. No classes (use structs for similar functionality)
3. No this keyword outside of struct methods
4. No new operator (constructors are just functions)
5. Limited error messages in some cases
6. No switch statements (use if-else chains)
7. No break or continue in loops
8. No try-catch error handling
9. No delete operator for object properties
10. No computed property names

---

Debugging

Logging

log('Value:', x, 'Another:', y)

Item Debugging

debugItem()  // Prints item information to console

Error Handling

The language has limited error handling. Use conditional checks to avoid errors:

if (item) {
    item.setPosX(100)
}

---

Quick Reference Card

┌───────────────────────────────────────────────────────────────┐
│                  SCHEMIO SCRIPT QUICK REFERENCE               │
├───────────────────────────────────────────────────────────────┤
│ VARIABLES: name = value           LOCAL: let name = value     │
│ IF: if (cond) { ... } else { ... }                            │
│ LOOPS: while (cond) { ... }    for (init; cond; step) { ... } │
│ FUNCTIONS: func f(a,b) { ... }    (a,b) => { ... }            │
│ ITEMS: @ItemName    @"Item 2"    @`Item ${i}`                 │
│ VECTOR: Vector(x,y)  v.length()  v.normalized()               │
│ LIST: List(a,b,c)   list.map()   list.filter()                │
│ MAP: Map(k1,v1,k2,v2)  map.get(k)  map.set(k,v)               │
│ SET: Set(a,b,c)  set.has(a)  set.add(b)                       │
│ STRUCT: struct Name { field: default, method() { ... } }      │
│ MATH: abs()  min()  max()  pow()  sqrt()  PI()  rnd()         │
│ COLOR: Color(r,g,b,a)  decodeColor(s)  color.gradient(c,t)    │
│ ITEM: getPosX()  setPos(x,y)  getWidth()  setText(slot, text) │
│ EVENT: sendEvent(name, args)  getEventName()  getEventArg(i)  │
└───────────────────────────────────────────────────────────────┘