libero/walker

Types

DiscoveredType

A custom type discovered by the walker, grouping all its variants.

pub type DiscoveredType {
  DiscoveredType(
    module_path: String,
    type_name: String,
    type_params: List(String),
    variants: List(DiscoveredVariant),
  )
}

Constructors

DiscoveredType(
  module_path: String,
  type_name: String,
  type_params: List(String),
  variants: List(DiscoveredVariant),
)

DiscoveredVariant

</>

A single discovered variant, used in typed decoder codegen.

pub type DiscoveredVariant {
  DiscoveredVariant(
    module_path: String,
    variant_name: String,
    atom_name: String,
    float_field_indices: List(Int),
    field_labels: List(option.Option(String)),
    fields: List(field_type.FieldType),
  )
}

Constructors

```
DiscoveredVariant(
  module_path: String,
  variant_name: String,
  atom_name: String,
  float_field_indices: List(Int),
  field_labels: List(option.Option(String)),
  fields: List(field_type.FieldType),
)
```
Arguments

module_path

Gleam module path, e.g. “shared/discount”.

variant_name

PascalCase constructor name, e.g. “AdminData”.

atom_name

snake_case atom name, e.g. “admin_data”.

float_field_indices

0-based indices of fields whose Gleam type is Float. Used by the JS ETF encoder to distinguish Int from Float (JS erases this distinction at runtime).

field_labels

Labels for each field. None for unlabelled, Some("label") for labelled. Carried alongside fields for JSON codegen; ignored by ETF codegen.

fields

Structured types of each field, in declaration order.

Values

qualified_atom_name

</>

pub fn qualified_atom_name(
  module_path module_path: String,
  variant_name variant_name: String,
) -> String

Build a module-qualified atom name from a module path and variant name. “shared/discount” + “Discount” → “shared_discount__discount”. Two modules with the same variant name produce distinct atoms, so the atom→decoder reverse mapping cannot collide.

to_snake_case

</>

pub fn to_snake_case(name: String) -> String

Convert a PascalCase variant name to snake_case for the wire atom. “AdminData” → “admin_data”, “One” → “one”, “TwoOrMore” → “two_or_more”. Handles consecutive uppercase: “XMLParser” → “xml_parser”. Must stay aligned with snakeCase() in etf/wire_ffi.mjs.

walk

</>

pub fn walk(
  seeds seeds: List(#(String, String)),
  file_paths file_paths: List(String),
) -> Result(List(DiscoveredType), List(gen_error.GenError))

Walk the type graph starting from seeds, discovering all reachable custom types. Seeds come from scanner output (param/return types of endpoints). file_paths are the .gleam files to search for type definitions. BFS traversal order affects discovery order but not correctness: all reachable types are found regardless of queue order.

Constructors

Constructors

Arguments