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Field

Field represents a class field (constructor parameter) in the IR. Combine a name with a type reference, optionally adding default values and modifiers.

Use Cases​

  • Defining constructor parameters for case classes
  • Specifying fields in abstract classes
  • Modeling data structure fields with optional defaults

Construction​

Build a field with a name and type:

import zio.blocks.codegen.ir._

val id = Field("id", TypeRef.Long)
val name = Field("name", TypeRef.String)
val email = Field("email", TypeRef.optional(TypeRef.String))

With default value:

import zio.blocks.codegen.ir._

val timeout = Field("timeout", TypeRef.Long, defaultValue = Some("5000L"))
val retries = Field("retries", TypeRef.Int, defaultValue = Some("3"))

With annotations:

import zio.blocks.codegen.ir._

val annotated = Field(
  "id",
  TypeRef.Long,
  annotations = List(Annotation("id"))
)

Key Operations​

All Field instances support these operations:

Accessing Components​

Extract parts of a field:

import zio.blocks.codegen.ir._

val field = Field("age", TypeRef.Int, defaultValue = Some("0"))

View field properties:

import zio.blocks.codegen.ir._

field.name           // "age"
// res4: String = "age"
field.typeRef        // TypeRef.Int
// res5: TypeRef = TypeRef(name = "Int", typeArgs = List())
field.defaultValue   // Some("0")
// res6: Option[String] = Some("0")
field.annotations    // List[Annotation]
// res7: List[Annotation] = List()

Building with Copy​

Modify a field using copy:

import zio.blocks.codegen.ir._

val field = Field("age", TypeRef.Int, defaultValue = Some("0"))

Apply modifications:

import zio.blocks.codegen.ir._

val updated = field.copy(
  defaultValue = Some("18"),
  annotations = List(Annotation("min"))
)
// updated: Field = Field(
//   name = "age",
//   typeRef = TypeRef(name = "Int", typeArgs = List()),
//   defaultValue = Some("18"),
//   annotations = List(Annotation(name = "min", args = List())),
//   doc = None
// )

Examples​

These examples show practical usage patterns for Field:

Example 1: Simple Fields​

Create fields for a case class:

import zio.blocks.codegen.ir._
import zio.blocks.codegen.emit._

val order = CaseClass(
  name = "Order",
  fields = List(
    Field("id", TypeRef.Long),
    Field("customerId", TypeRef.String),
    Field("total", TypeRef("BigDecimal")),
    Field("status", TypeRef.String)
  )
)

val file = ScalaFile(
  packageDecl = PackageDecl("com.shop"),
  types = List(order)
)

Emits:

import zio.blocks.codegen.emit._

ScalaEmitter.emit(file, EmitterConfig())
// res10: String = """package com.shop
// 
// case class Order(
//   id: Long,
//   customerId: String,
//   total: BigDecimal,
//   status: String,
// )
// """

Example 2: Fields with Defaults​

Case class fields with default values:

import zio.blocks.codegen.ir._
import zio.blocks.codegen.emit._

val config = CaseClass(
  name = "DatabaseConfig",
  fields = List(
    Field("host", TypeRef.String, defaultValue = Some("\"localhost\"")),
    Field("port", TypeRef.Int, defaultValue = Some("5432")),
    Field("timeout", TypeRef.Long, defaultValue = Some("30000L"))
  )
)

val file = ScalaFile(
  packageDecl = PackageDecl("com.example"),
  types = List(config)
)

Emits:

import zio.blocks.codegen.emit._

ScalaEmitter.emit(file, EmitterConfig())
// res12: String = """package com.example
// 
// case class DatabaseConfig(
//   host: String = "localhost",
//   port: Int = 5432,
//   timeout: Long = 30000L,
// )
// """

Example 3: Optional and Collection Fields​

Fields with generic types:

import zio.blocks.codegen.ir._
import zio.blocks.codegen.emit._

val article = CaseClass(
  name = "Article",
  fields = List(
    Field("title", TypeRef.String),
    Field("content", TypeRef.String),
    Field("author", TypeRef.optional(TypeRef.String)),
    Field("tags", TypeRef.list(TypeRef.String)),
    Field("metadata", TypeRef.map(TypeRef.String, TypeRef.String))
  )
)

val file = ScalaFile(
  packageDecl = PackageDecl("com.example"),
  types = List(article)
)

Emits:

import zio.blocks.codegen.emit._

ScalaEmitter.emit(file, EmitterConfig())
// res14: String = """package com.example
// 
// case class Article(
//   title: String,
//   content: String,
//   author: Option[String],
//   tags: List[String],
//   metadata: Map[String, String],
// )
// """

Example 4: Nested Generic Types​

Complex field types:

import zio.blocks.codegen.ir._
import zio.blocks.codegen.emit._

val response = CaseClass(
  name = "Response",
  fields = List(
    Field(
      "data",
      TypeRef("Option", List(
        TypeRef("List", List(TypeRef.String))
      ))
    ),
    Field(
      "errors",
      TypeRef("List", List(
        TypeRef("Map", List(TypeRef.String, TypeRef.String))
      ))
    )
  )
)

val file = ScalaFile(
  packageDecl = PackageDecl("com.example"),
  types = List(response)
)

Emits:

import zio.blocks.codegen.emit._

ScalaEmitter.emit(file, EmitterConfig())
// res16: String = """package com.example
// 
// case class Response(
//   data: Option[List[String]],
//   errors: List[Map[String, String]],
// )
// """

Example 5: Fields with Type Parameters​

Fields using generic type variables:

import zio.blocks.codegen.ir._
import zio.blocks.codegen.emit._

val page = CaseClass(
  name = "Page",
  fields = List(
    Field("items", TypeRef("List", List(TypeRef("T")))),
    Field("total", TypeRef.Long),
    Field("pageSize", TypeRef.Int)
  ),
  typeParams = List(TypeParam("T"))
)

val file = ScalaFile(
  packageDecl = PackageDecl("com.example"),
  types = List(page)
)

Emits:

import zio.blocks.codegen.emit._

ScalaEmitter.emit(file, EmitterConfig())
// res18: String = """package com.example
// 
// case class Page[T](
//   items: List[T],
//   total: Long,
//   pageSize: Int,
// )
// """