Module compiler

`macro`

Macros are Coil functions that run at compile time and return code. A derive receives a TypeDecl, an attribute macro an FnDecl or TypeDecl, and a function-style macro (name!(…)) its arguments as Expr. Each returns Code, usually built with a quote block. See Macros and the macros tutorial.

Written in Coil and shipped inside the compiler.

Import what you use (use path::* is not allowed):

use macro::{Code, Ident};

Types#

Name	Description
`Code`	Generated coil source: declarations, an expression, statements or a type.
`Ident`	A name as written in source.
`Expr`	A function-style macro argument as written: `f(1)`, `a + b`, `"text"`.
`TypeRef`	A type annotation as written (not resolved): `Vec<int>`, `json::Value`.
`AttrArg`	One `key = value` (or positional `value`, with `key == ""`) attribute argument.
`Attr`	`#[name(args)]` on a declaration, field or variant.
`Field`	A class field, or a field of a record enum variant.
`Variant`	One enum variant.
`TypeDecl`	A class or enum declaration handed to a derive or attribute macro.
`Param`	One function parameter.
`FnDecl`	A function or method handed to an attribute macro.
`Reader`	Reads a macro call’s input: length-prefixed fields (`<len>:<bytes>`, lists as a count then their items) in constructor order, written by the compiler (`macros::encode`).

Functions#

Name	Description
`join`	Join fragments with `sep` (the lowering of `$(xs) sep *`).
`lit`	A string literal: `lit("a\"b")` splices as `"a\"b"`.
`lit_int`	An integer literal.
`raw`	Raw source, spliced as is.
`concat`	Combine several generated item lists.
`ident`	A name, for splicing generated identifiers: `${ident("to_" + n)}`.
`decimal`	A decimal integer the compiler wrote (`-` then digits, in range).
`attr_index`	Index of the attribute called `name`, or `-1`.
`attr_value`	`#[attr(key = "value")]` from an attribute list, or `fallback`.