Documentation
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Overview ¶
Package tomlbind decodes one TOML document into a struct through generated code, and imports nothing of configbind.
configbind answers "load my service's settings": it layers a TOML file, environment variables and command-line options onto one struct, and links the parsers for all three to do it. This package is the TOML layer on its own, for a program that reads a file and wants nothing else.
settings, err := tomlbind.DecodeTOML[Settings](file)
Calling an entry point is the ask. The generator reads the call, emits the decoder, and puts the DecodeTOMLFrom method on the type, so the second build compiles and every build after that is an ordinary method call. A type with no generated method does not satisfy the constraint, and the call site fails to build rather than failing at the first read.
Declaring a decoder ¶
Generation is per package, and the method lands on the type, so a type that is decoded from another package declares its decoder beside itself:
var _ = tomlbind.GenerateDecoder[Settings]()
What a document may hold ¶
The parser is minitoml, which reads the configuration subset configbind reads: tables, dotted bare keys, string, bool, integer and float scalars, arrays of scalars, and arrays of tables. Quoted keys, inline tables and nested arrays are refused. The struct's key and default tags are the ones configbind reads, so one struct serves both.
This package imports io and nothing else ¶
The interface below is spelled in bytes, so minitoml is named only by the generated code that calls it.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func DecodeTOML ¶
DecodeTOML reads r to its end and decodes the document into a T. PT is inferred from T, so a call site writes one type argument:
settings, err := tomlbind.DecodeTOML[Settings](file)
A document is read once at startup, so it is read whole rather than streamed; a size limit is the caller's io.LimitReader.
Types ¶
type Declaration ¶
type Declaration struct{}
Declaration is what GenerateDecoder returns. It carries nothing: the value exists only so the annotation can be written as a package-level declaration, which is where generation reads it.
func GenerateDecoder ¶
func GenerateDecoder[T any]() Declaration
GenerateDecoder asks for T's decoder without a call site to derive it from. Write it at package level, beside the type:
var _ = tomlbind.GenerateDecoder[Settings]()
The call runs at init and does nothing. The declaration is the point.
Source Files