# Cadlang design

## Geometry
We can provide primitive geometries like Points, Lines, Rectangles like this.

Then to build other geometries, definitions of a geometry contains either primitive geometries or other geometry

// Pure geometry implementation

define Rectangle : Geometry {
    a1 : Points 
    a2 : Points
    a3 : Points
    a4 : Points
};

// Self contained constraint
impl Constraint for Rectangle {
   // ...  
}

// Mixed Implementation
define House : Geometry {
    r : Rectangle,
    l1 : Line,
    l2 : Line,
};

impl Constraint for House {

}

Then a usage would be

let rect = Rectangle {
    a1 : (1, 1)
    a2 : (2, 2)
    a3 : (1, 2)
    a4 : (2, 1)
}

Define primitives
Define a set of constraints: Distance, Alignment, Ordering of fields

### Constraints between geometries

We can define constraints via pairs of geometries?!

// Here, the constraint dictates that r1 is the centre.

// Suppose I edit some points of r1, r2 will adjusts automatically
// if i edit some points of r2, then the program logs this as an error

define C1 : MovableConstraint(r1 : Rectangle, r2 : Rectangle) {

};

// Here, no matter whose's element i change, i will get an error
define C2 : PanicConstraint(r1 : Rectangle, r2 : Rectangle) {
    
};

For impl, we can think of some kind of graph???:
For example, if b needs to be 2 units to the right of a, and 1 units up of a

then the constraint graph shows

a -> [{b, (1, 2)}]

> Is all elements tilable?

I think tiling suggests some kind of inferrence on the coordinates of the geometry.

Also what does tiling on a grid means???

// ONGOING WORK
// TODO

## Utilities

Maybe we need some kind of ports
## Vias/layers

Think about layers as some kind of group/scope

Maybe do the cell

Layer layer_1 {
    ...
    
    ...
    
    ...
    #tag(draw_my_fav)
    let rec : Rec = ...
    draw(layer_1, rec)
}

Layer layer_2 {
    ...
    
    ...
    
    ...
}


draw layer_1 layer_2
// or
draw layer_1 
draw layer_2

We need these information for gds format

 // Required fields
    /// Library name.
    pub name: ArcStr,
    /// Gds spec version.
    pub version: i16,
    /// Modification date(s).
    pub dates: GdsDateTimes,
    /// Spatial units.
    pub units: GdsUnits,
    /// Struct definitions.
    pub structs: Vec<GdsStruct>,

    // Unsupported Fields
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub libdirsize: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub srfname: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub libsecur: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub reflibs: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub fonts: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub attrtable: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub generations: Unsupported,
    #[serde(default, skip_serializing)]
    #[builder(default)]
    pub format_type: Unsupported,
}

Minimal is name and version

## Design Doc

### Lexer & Parser

We'll use logos and chumsky for lexing and parsing.