Struct ConstraintTypeDef 

pub struct ConstraintTypeDef {
    pub type_id: &'static str,
    pub short_name: &'static str,
    pub icon: &'static str,
    pub long_name: &'static str,
    pub label: &'static str,
    pub min_elements: usize,
    pub max_elements: usize,
    pub duplicate_family: bool,
    pub applicable: fn(&SelectionProbe) -> bool,
}

One constraint type’s static definition.

Fields

type_id: &'static str

Canonical type string (lowercase snake — the persisted key).

short_name: &'static str

Id-mint prefix (CONC → CONC3).

icon: &'static str

The type’s ONE icon — a single catalogued glyph character (the app’s assets/glyphs catalog, where Coincident shares ≡ with the sketch solver’s coincident). Every surface that stands for the type by picture alone — the workbench toolbar button, the viewport chip, the tree row’s glyph column — reads THIS field; nothing derives it from long_name.

long_name: &'static str

Display label: "{icon} {label}" (the context bar draws the leading glyph as artwork). Pinned to the other two by a test below.

label: &'static str

Plain label for messages (“Duplicate … conflicts with Distance constraint DIST4.”).

min_elements: usize

The accepted elements count range, inclusive: fixed takes exactly 1, the pairing types exactly 2, center 3 or 4 (two width faces plus a one- or two-element tab). The lifecycle marks a count outside the range incomplete; the schema’s minSelections/maxSelections mirror it.

max_elements: usize

duplicate_family: bool

Member of the duplicate-detection family (overlapping selection pairs conflict across these types — requirements §4.3).

applicable: fn(&SelectionProbe) -> bool

Selection-context applicability (the feature context_applicable pattern, [crate::feature_pipeline::context_offer]): does the current selection make creating this constraint meaningful? Every element must be component geometry ([super::mapping]’s resolve_element rejects everything else), and the counted kinds are the ones the app’s element seeder can actually produce (faces/edges, solids as COMPONENT refs — never vertices, whose @-refs only the modal picker builds).