nomix

package
v0.11.0 Latest Latest
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 Go to latest Published: Jun 7, 2026 License: MIT Imports: 11 Imported by: 0

Documentation

Overview

Package nomix provides a set of types and functions for handling tags and metadata in a generic way.

Index

Examples

Constants

View Source 
const (
	KindBool = 0b00000001_00000000 | KindInt64
	KindInt  = 0b00000010_00000000 | KindInt64
)

Derived Tag kinds. Derived kinds are types that are derived from base kinds.

View Source 
const (
	KindByteSlice    = 0b00000000_00000001 | KindSlice
	KindStringSlice  = KindString | KindSlice
	KindInt64Slice   = KindInt64 | KindSlice
	KindFloat64Slice = KindFloat64 | KindSlice
	KindTimeSlice    = KindTime | KindSlice
	KindUUIDSlice    = KindUUID | KindSlice
	KindBoolSlice    = KindBool | KindSlice
	KindIntSlice     = KindInt | KindSlice
)

Multi value (slice) Tag kinds.

View Source 
const KindSpecName = "kind-spec"

KindSpecName identifies KindSpec in a spec.Spec.

Variables

View Source 
var (
	// ErrInvType represents an invalid element type.
	ErrInvType = errors.New("invalid element type")

	// ErrInvFormat represents an invalid element format.
	ErrInvFormat = errors.New("invalid element format")

	// ErrMissing represents a missing set element.
	ErrMissing = errors.New("missing element")

	// ErrInvValue represents an invalid element value.
	ErrInvValue = errors.New("invalid element value")

	// ErrNoCreator represents a missing tag creator for a type.
	ErrNoCreator = errors.New("creator not found")

	// ErrNoSpec represents a missing tag spec for a type.
	ErrNoSpec = errors.New("spec not found")

	// ErrNotImpl represents a missing method implementation or
	// functionality for a type.
	ErrNotImpl = errors.New("not implemented")
)

Metadata parsing and casting errors.

Functions

func CreateFloat64 added in v0.2.0 

func CreateFloat64(val any) (float64, error)

CreateFloat64 casts the value to float64. Returns the float64 and nil error if the value is a byte, int, int8, int16, int32, int64, float32, or float64. Returns 0.0 and ErrInvType if the value's type is not a supported numeric type. Returns 0.0 and ErrInvValue if an int or int64 value falls outside the ±2^53 range where float64 cannot represent integers exactly.

func CreateFloat64Slice added in v0.2.0 

func CreateFloat64Slice(val any) ([]float64, error)

CreateFloat64Slice casts the value to []float64. Returns the slice and nil error if the value is a []int, []int8, []int16, []int32, []int64, []float32, or []float64. Returns nil and ErrInvType if the value's type is not a supported numeric slice type.

NOTE: For values outside ±2^53 range, the function will return an error.

func CreateInt64 added in v0.2.0 

func CreateInt64(val any) (int64, error)

CreateInt64 casts the value to int64. Returns the int64 and nil error if the value is a byte, int, int8, int16, int32, or int64. Returns 0 and ErrInvType if the value is not a supported integer type.

func CreateInt64Slice added in v0.2.0 

func CreateInt64Slice(val any) ([]int64, error)

CreateInt64Slice casts the value to []int64. Returns the []int64 and nil error if the value is a []int, []int8, []int16, []int32, or []int64. Returns nil and ErrInvType if the value's type is not a supported numeric slice type.

func CreateTime added in v0.2.0 

func CreateTime(val any, opts Options) (time.Time, error)

CreateTime casts the value to time.Time or when the value is a string parses it in the given location but only when the format is provided. Returns the time and nil error on success. Returns zero value time and error if the value's type is not a supported type or the value is not a valid time representation.

func CreateTimeSlice added in v0.2.0 

func CreateTimeSlice(val any, opts Options) ([]time.Time, error)

CreateTimeSlice casts the value to []time.Time, or when the value is a []string, it parses its elements in the given location but only when the format is provided. With the "zvt" argument you may provide a list of strings representing zero value time. Returns the []time.Time and nil error on success. Returns nil and error if the value's type is not a supported type or the value is not a valid time representation.

func GetMetaValue added in v0.5.0 

func GetMetaValue[T any](set MetaSet, name string) (T, error)

GetMetaValue retrieves the value of type T from the set. Returns the value if found, or the zero value for T and error.

func GetTag added in v0.5.0 

func GetTag[T any](set TagSet, name string) (T, error)

GetTag retrieves the Tag of type T from the set. Returns the Tag if found, or the zero value for T and error.

func GetTagValue added in v0.5.0 

func GetTagValue[T any](set TagSet, name string) (T, error)

GetTagValue retrieves the value of the Tag of type T from the set. Returns the value if found, or the zero value for T and error.

func IsInternalError added in v0.6.0 

func IsInternalError(err error) bool

IsInternalError reports whether the error is non-nil InternalError.

func IsNomixError added in v0.9.0 

func IsNomixError(err error) bool

IsNomixError reports whether the error is non-nil Error, FieldErrors or InternalError.

func IsValidationError added in v0.6.0 

func IsValidationError(err error) bool

IsValidationError reports whether the error is non-nil Error or FieldErrors.

func NewError added in v0.6.0 

func NewError(msg string, args ...any) error

NewError creates a new Error with the given message. The args may contain an optional string error code and any number of xrr.Option values in any order.

Examples: 

NewError("message")
NewError("message", "ECode")
NewError("message", "ECode", xrr.Option())

When xrr.WithCause is provided:

  • If msg is empty, Error() returns the cause's message directly.
  • If msg is non-empty, Error() returns "msg: cause message".
  • If no code is given and xrr.WithCode is not provided, the cause's code is inherited via xrr.GetCode. Pass a code string or xrr.WithCode to override it.

For wrapping without a new message, prefer xrr.Wrap, which makes the intent clearer.

func NewErrorf added in v0.8.1 

func NewErrorf(format string, args ...any) error

NewErrorf creates a new Error using a format string. It is the format-style counterpart of NewError: non-xrr.Option args are passed to the format string, while xrr.Option values are applied to the error. Unlike NewError, a bare string argument is treated as a format argument, not an error code — pass xrr.WithCode to set the code.

When the format string contains %w, the error is created via fmt.Errorf and stored as the cause; xrr.GenericError.Error delegates to it. Without %w, the message is set to fmt.Sprintf(format, args...).

Examples: 

NewErrorf("user %d not found", userID)
NewErrorf("user %d not found", userID, xrr.WithCode("ECode"))
NewErrorf("connect failed: %w", err)
NewErrorf("connect failed: %w", err, xrr.WithCode("ECode"))

func NewInternalError added in v0.6.0 

func NewInternalError(msg string, args ...any) error

NewInternalError creates a new InternalError with the given message. The args may contain an optional string error code and any number of xrr.Option values in any order.

Examples: 

NewInternalError("message")
NewInternalError("message", "ECode")
NewInternalError("message", "ECode", xrr.Option())

When xrr.WithCause is provided:

  • If msg is empty, Error() returns the cause's message directly.
  • If msg is non-empty, Error() returns "msg: cause message".
  • If no code is given and xrr.WithCode is not provided, the cause's code is inherited via xrr.GetCode. Pass a code string or xrr.WithCode to override it.

For wrapping without a new message, prefer xrr.Wrap, which makes the intent clearer.

func NewInternalErrorf added in v0.8.1 

func NewInternalErrorf(format string, args ...any) error

NewInternalErrorf creates a new InternalError using a format string. It is the format-style counterpart of NewInternalError: non-xrr.Option args are passed to the format string, while xrr.Option values are applied to the error. Unlike NewInternalError, a bare string argument is treated as a format argument, not an error code — pass xrr.WithCode to set the code.

When the format string contains %w, the error is created via fmt.Errorf and stored as the cause; xrr.GenericError.Error delegates to it. Without %w, the message is set to fmt.Sprintf(format, args...).

Examples: 

NewInternalErrorf("user %d not found", userID)
NewInternalErrorf("user %d not found", userID, xrr.WithCode("ECode"))
NewInternalErrorf("connect failed: %w", err)
NewInternalErrorf("connect failed: %w", err, xrr.WithCode("ECode"))

func ParseTime 

func ParseTime(val string, opts Options) (time.Time, error)

ParseTime parses a string representation of time.Time. Returns the time and nil error if the value is a valid time representation. Returns zero value time and ErrInvFormat if the value is not a valid time representation.

func WithLocString 

func WithLocString(opts *Options)

WithLocString is the MetaSet option allowing string timezone names.

func WithRadixHEX added in v0.5.0 

func WithRadixHEX(opts *Options)

WithRadixHEX sets base to hexadecimal when parsing integers.

Types

type AllGetter added in v0.5.0 

type AllGetter interface {
	// TagGetAll returns all tags in the set as a map. May return nil. The
	// returned map should be treated as read-only.
	TagGetAll() map[string]Tag
}

AllGetter is an interface for retrieving all tags in the set.

type Comparer added in v0.5.0 

type Comparer interface {
	// TagSame returns true if both tags have the same name, kind and value.
	TagSame(other Tag) bool
}

Comparer is an interface for comparing tags.

type CreateFunc added in v0.2.0 

type CreateFunc func(name string, val any, opts ...Option) (Tag, error)

CreateFunc function signature for creating Tag instances.

Example 
package main

import (
	"database/sql/driver"
	"fmt"
	"strconv"

	"github.com/ctx42/nomix/pkg/nomix"
)

func main() {
	type Int = nomix.Single[int]

	// CreateInt is a function creating a new [Int] instance by casting
	// argument "val" to int.
	var CreateInt = func(name string, val any, opts ...nomix.Option) (*Int, error) {
		if v, ok := val.(int); ok {
			sqlValue := func(val int) (driver.Value, error) {
				return int64(val), nil
			}
			return nomix.NewSingle(name, v, nomix.KindInt, strconv.Itoa, sqlValue), nil
		}
		return nil, nomix.ErrInvType
	}

	var tcf nomix.CreateFunc
	tcf = nomix.TagCreateFunc(CreateInt)

	tag, err := tcf("A", 42)
	format := "name: %s; kind: %s; value: %v; err: %v\n"
	fmt.Printf(format, tag.TagName(), tag.TagKind(), tag.TagValue(), err)
}

Output:
name: A; kind: KindInt; value: 42; err: <nil>

func TagCreateFunc added in v0.2.0 

func TagCreateFunc[T Tag](fn func(name string, val any, opts ...Option) (T, error)) CreateFunc

TagCreateFunc creates a CreateFunc from a function that creates concrete tag instances.

Examples: 

TagCreateFunc(func(name string, val any, opts ...Option) (MyTag, error))

type Creator added in v0.5.0 

type Creator interface {
	// TagCreate creates the appropriate [Tag] instance based on the value's
	// type. It returns the [ErrNoCreator] error if the value's type is not
	// supported. The name must be set by the implementer.
	TagCreate(value any, opts ...Option) (Tag, error)
}

Creator is an interface for creating Tag instances.

type Definition added in v0.2.0 

type Definition struct {
	// contains filtered or unexported fields
}

Definition represents a named tag definition. In other words, it wraps a KindSpec and a tag name.

func Define added in v0.2.0 

func Define(name string, spec KindSpec, rules ...verax.Rule) *Definition

Define defines named Tag.

Example 
package main

import (
	"fmt"

	"github.com/ctx42/verax/pkg/verax"

	"github.com/ctx42/nomix/pkg/nomix"
	"github.com/ctx42/nomix/pkg/xtag"
)

func main() {
	def := nomix.Define("name", xtag.IntSpec(), verax.Max(42))

	tag, err := def.TagCreate(42)
	fmt.Printf("- success: %s err: %v\n", tag, err)

	tag, err = def.TagCreate(44)
	fmt.Printf("- failure: %v err: %v\n", tag, err)

}

Output:
- success: 42 err: <nil>
- failure: <nil> err: name: must be less or equal to 42

func (*Definition) TagCreate added in v0.2.0 

func (def *Definition) TagCreate(val any, opts ...Option) (Tag, error)

TagCreate creates a new Tag matching the definition. It validates the value when a rule is set.

func (*Definition) TagKind added in v0.2.0 

func (def *Definition) TagKind() Kind

TagKind returns the tag definition kind.

func (*Definition) TagName added in v0.2.0 

func (def *Definition) TagName() string

TagName returns the tag name definition is for.

func (*Definition) TagParse added in v0.2.0 

func (def *Definition) TagParse(val string, opts ...Option) (Tag, error)

TagParse creates a new Tag from its string representation. It validates the parsed value when a rule is set.

func (*Definition) TagRule added in v0.8.0 

func (def *Definition) TagRule() verax.Rule

TagRule returns the validation rule associated with the definition, or nil if none was provided.

func (*Definition) Validate added in v0.3.0 

func (def *Definition) Validate(val any) error

Validate validates the given value against the definition.

NOTE: The Creator is first used to create a Tag instance with the provided value; hence all types supported by Creator are supported.

type Error added in v0.6.0 

type Error = xrr.GenericError[edError]

Error represents an error in the package's error domain.

type FieldErrors added in v0.6.0 

type FieldErrors = xrr.GenericFields[edError]

FieldErrors represents a field error in the package's error domain.

func NewFieldError added in v0.6.0 

func NewFieldError(field string, err error) *FieldErrors

NewFieldError returns a new field error in the package's error domain.

func NewFieldErrors added in v0.6.0 

func NewFieldErrors(fields map[string]error) *FieldErrors

NewFieldErrors creates a new FieldErrors from the given map. The map is stored directly without copying.

type InternalError added in v0.6.0 

type InternalError = xrr.GenericError[edInternal]

InternalError represents an internal error (library misuse) in the package's error domain.

type Kind added in v0.5.0 

type Kind int16

Kind describes the type of Tag value. 

const (
	KindString  Kind = 0b00000000_00000010
	KindInt64   Kind = 0b00000000_00000100
	KindFloat64 Kind = 0b00000000_00001000
	KindTime    Kind = 0b00000000_00010000
	KindJSON    Kind = 0b00000000_00100000
	KindUUID    Kind = 0b00000000_01000000
)

Base Tag kinds. 

const KindSlice Kind = 0b00000000_10000000

KindSlice is a Kind type modifier indicating it is a slice.

func (Kind) String added in v0.5.0 

func (tk Kind) String() string

String implements fmt.Stringer.

nolint: cyclop

type KindSpec added in v0.2.0 

type KindSpec struct {
	// contains filtered or unexported fields
}

KindSpec is a specification for a tag kind.

func KindSpecFromSpec added in v0.6.0 

func KindSpecFromSpec(reg *Registry, spc *spec.Spec) (KindSpec, error)

KindSpecFromSpec creates a KindSpec from a spec.Spec. The Kind encoded in the spec must be registered in the global Registry at the time this function is called.

func NewKindSpec added in v0.2.0 

func NewKindSpec(knd Kind, tcr CreateFunc, tpr ParseFunc) KindSpec

NewKindSpec creates a new KindSpec instance.

Example 
package main

import (
	"fmt"

	"github.com/ctx42/nomix/pkg/nomix"
	"github.com/ctx42/nomix/pkg/xtag"
)

func main() {
	spec := nomix.NewKindSpec(
		nomix.KindInt,
		nomix.TagCreateFunc(xtag.CreateInt),
		nomix.TagParseFunc(xtag.ParseInt),
	)

	tagA, errA := spec.TagCreate("A", 42)
	tagB, errB := spec.TagParse("B", "42")

	fmt.Printf("- A: %v err: %v\n", tagA.TagValue(), errA)
	fmt.Printf("- B: %v err: %v\n", tagB.TagValue(), errB)
}

Output:
- A: 42 err: <nil>
- B: 42 err: <nil>

func (KindSpec) IsZero added in v0.2.0 

func (ks KindSpec) IsZero() bool

IsZero reports whether the spec is a zero value (no kind, creator, or parser assigned).

func (KindSpec) Spec added in v0.6.0 

func (ks KindSpec) Spec() (*spec.Spec, error)

func (KindSpec) TagCreate added in v0.2.0 

func (ks KindSpec) TagCreate(
	name string,
	value any,
	opts ...Option,
) (Tag, error)

TagCreate creates a new Tag matching the Kind in the spec.

func (KindSpec) TagKind added in v0.6.0 

func (ks KindSpec) TagKind() Kind

TagKind returns the Kind the spec is for.

func (KindSpec) TagParse added in v0.2.0 

func (ks KindSpec) TagParse(name, val string, opts ...Option) (Tag, error)

TagParse creates a Tag based on its string representation.

type MetaAllGetter 

type MetaAllGetter interface {
	// MetaGetAll returns all tags in the set as a map. May return nil. The
	// returned map should be treated as read-only.
	MetaGetAll() map[string]any
}

MetaAllGetter is an interface wrapping MetaGetAll method.

type MetaAllSetter 

type MetaAllSetter interface {
	// MetaSetAll sets metadata on the implementor. If the value with the given
	// name already exists in the set, it will be overwritten. The nil values
	// must be ignored.
	MetaSetAll(map[string]any)
}

MetaAllSetter is an interface wrapping MetaSetAll method.

type MetaAppender 

type MetaAppender interface {
	// MetaAppend appends all implementor metadata to the passed map.
	MetaAppend(map[string]any)
}

MetaAppender is an interface wrapping MetaAppend method.

type MetaFromGetter 

type MetaFromGetter interface {
	// MetaSetFrom sets metadata on the implementor from the [MetaAllGetter].
	MetaSetFrom(src MetaAllGetter)
}

MetaFromGetter is an interface wrapping MetaFromGetter method.

type MetaSet 

type MetaSet struct {
	// contains filtered or unexported fields
}

MetaSet represents a set of metadata key-values.

Example 
package main

import (
	"fmt"

	"github.com/ctx42/nomix/pkg/nomix"
)

func main() {
	set := nomix.NewMetaSet()

	set.MetaSet("A", 42)
	set.MetaSet("B", true)
	set.MetaSet("C", "foo")

	fmt.Printf("There are %d entries in the set:\n", set.MetaCount())
	fmt.Printf("- A: %v\n", set.MetaGet("A"))
	fmt.Printf("- B: %v\n", set.MetaGet("B"))
	fmt.Printf("- C: %v\n", set.MetaGet("C"))
	fmt.Printf("- D: %v\n", set.MetaGet("D"))

}

Output:
There are 3 entries in the set:
- A: 42
- B: true
- C: foo
- D: <nil>

func NewMetaSet 

func NewMetaSet(opts ...Option) MetaSet

NewMetaSet returns a new MetaSet instance. By default, no initial capacity is reserved.

func (MetaSet) MetaCount 

func (set MetaSet) MetaCount() int

MetaCount returns the number of entries in the metadata set.

func (MetaSet) MetaDelete 

func (set MetaSet) MetaDelete(key string)

func (MetaSet) MetaDeleteAll 

func (set MetaSet) MetaDeleteAll()

MetaDeleteAll deletes all metadata from the set.

func (MetaSet) MetaGet 

func (set MetaSet) MetaGet(key string) any

func (MetaSet) MetaGetAll 

func (set MetaSet) MetaGetAll() map[string]any

func (MetaSet) MetaSet 

func (set MetaSet) MetaSet(key string, value any)

type Metadata 

type Metadata interface {
	// MetaGet retrieves from the set a metadata value by its name. If the name
	// does not exist in the set, it returns nil.
	MetaGet(name string) any

	// MetaSet adds a named value to the set. If the value with the given name
	// already exists in the set, it will be overwritten. Setting a nil value
	// must be implemented as a no-op.
	MetaSet(name string, value any)

	// MetaDelete removes from the set the metadata value by name. If the name
	// does not exist, the method has no effect.
	MetaDelete(name string)
}

Metadata is an interface for managing a collection of distinctly named metadata values. The implementations must not allow for nil values to be stored in the set.

type NamedCreator added in v0.5.0 

type NamedCreator interface {
	// TagCreate creates the appropriate [Tag] instance based on the value's
	// type. It returns the [ErrNoCreator] error if the value's type is not
	// supported.
	TagCreate(name string, value any, opts ...Option) (Tag, error)
}

NamedCreator is an interface for creating named Tag instances.

type NamedParser added in v0.5.0 

type NamedParser interface {
	TagParse(val string, opts ...Option) (Tag, error)
}

NamedParser is an interface for creating named Tag instances from their string representation. The name must be set by the implementer.

type Option 

type Option func(*Options)

Option represents an option function.

func WithLen 

func WithLen(n int) Option

WithLen is an option to set the default length for the map.

func WithMeta 

func WithMeta(m map[string]any) Option

WithMeta is an option to set the initial map for the MetaSet.

The caller must not use the passed map after the call to this option. The MetaSet becomes its new owner.

func WithTags 

func WithTags(m map[string]Tag) Option

WithTags is an option to set the initial map for the TagSet.

The caller must not use the passed map after the call to this option. The TagSet becomes its new owner.

func WithTimeFormat 

func WithTimeFormat(format string) Option

WithTimeFormat is the MetaSet option setting string time format.

func WithTimeLoc 

func WithTimeLoc(loc *time.Location) Option

WithTimeLoc is the MetaSet option setting location for parsed time strings.

func WithZeroTime 

func WithZeroTime(zero ...string) Option

WithZeroTime is MetaSet option setting zero time values.

type Options 

type Options struct {
	// Initial map size.
	//
	// Used by [NewTagSet] and [NewMetaSet] to allocate the init map.
	Length int

	// Time format.
	//
	// When set, [MetaSet.MetaGetTime] will allow time to be represented as a
	// string.
	TimeFormat string

	// Location to parse the time format.
	//
	// When set [time.ParseInLocation] instead of [time.Parse] in the
	// [MetaSet.MetaGetTime] to parse strings.
	Location *time.Location

	// When set, allows a timezone to be represented as a string.
	//
	// Example:
	//   Europe/Warsaw
	LocationAsString bool

	// The base for integers when parsing.
	Radix int
	// contains filtered or unexported fields
}

Options represent a set of options used by MetaSet and TagSet.

func NewOptions added in v0.5.0 

func NewOptions(opts ...Option) Options

NewOptions returns a new Options instance with default values.

type ParseFunc added in v0.2.0 

type ParseFunc func(name, val string, opts ...Option) (Tag, error)

ParseFunc function signature for creating Tag instances from their string representation.

func TagParseFunc added in v0.2.0 

func TagParseFunc[T Tag](fn func(name string, val string, opts ...Option) (T, error)) ParseFunc

TagParseFunc creates a ParseFunc from a function that creates concrete tag instances from their string representation.

Examples: 

TagParseFunc(func(name string, val string, opts ...Option) (T, error))

type Parser added in v0.5.0 

type Parser interface {
	TagParse(name string, val string, opts ...Option) (Tag, error)
}

Parser is an interface for creating Tag instances from their string representation.

type Registry added in v0.2.0 

type Registry struct {
	// contains filtered or unexported fields
}

Registry represents a collection of [Spec]s.

Example 
package main

import (
	"fmt"

	"github.com/ctx42/nomix/pkg/nomix"
	"github.com/ctx42/nomix/pkg/xtag"
)

func main() {
	reg := nomix.NewRegistry()

	_ = reg.Register(xtag.IntSpec())       // Register spec.
	_, _ = reg.Associate(0, nomix.KindInt) // Associate the int type with spec.

	spec := reg.SpecForKind(nomix.KindInt) // Get spec for KindInt.
	tag, err := spec.TagCreate("A", 42)
	format := "name: %s; kind: %s; value: %v; err: %v\n"
	fmt.Printf(format, tag.TagName(), tag.TagKind(), tag.TagValue(), err)

	spec = reg.SpecForType(0) // Get spec for int type.
	tag, err = spec.TagCreate("B", 44)
	fmt.Printf(format, tag.TagName(), tag.TagKind(), tag.TagValue(), err)

	// Convenience function to create tags for registered types.
	tag, err = reg.Create("C", 11)
	fmt.Printf(format, tag.TagName(), tag.TagKind(), tag.TagValue(), err)

}

Output:
name: A; kind: KindInt; value: 42; err: <nil>
name: B; kind: KindInt; value: 44; err: <nil>
name: C; kind: KindInt; value: 11; err: <nil>

func GlobalRegistry added in v0.5.0 

func GlobalRegistry() *Registry

GlobalRegistry returns the global, shared Registry instance initialised by the package. All callers share this instance; Registry.Register and Registry.Associate are safe for concurrent use but modify global state. Use NewRegistry when isolation is required.

func NewRegistry added in v0.2.0 

func NewRegistry() *Registry

NewRegistry returns a new Registry instance.

func (*Registry) Associate added in v0.5.0 

func (reg *Registry) Associate(typ any, knd Kind) (Kind, error)

Associate links a Go type to the given Kind, overwriting any existing association. Returns the previous kind association or Kind(0) if none. Returns an error if no KindSpec is registered for the kind.

func (*Registry) Create added in v0.2.0 

func (reg *Registry) Create(name string, val any, opts ...Option) (Tag, error)

Create creates a new Tag for the given value. The value's type must be registered.

func (*Registry) Register added in v0.2.0 

func (reg *Registry) Register(spec KindSpec) error

Register registers a KindSpec for the given Kind. Returns nil if successful, or an error if the kind is already registered. Each kind can have only one spec. Must be called before associating Go types with a KindSpec.

func (*Registry) SpecForKind added in v0.5.0 

func (reg *Registry) SpecForKind(knd Kind) KindSpec

SpecForKind retrieves the KindSpec for the given Kind. Use KindSpec.IsZero to check if a spec exists for the kind.

func (*Registry) SpecForType added in v0.5.0 

func (reg *Registry) SpecForType(typ any) KindSpec

SpecForType retrieves the KindSpec for the given type. Requires prior type association with a KindSpec. Use [Spec.IsZero] to check if a spec is available for the type.

type Single added in v0.5.0 

type Single[T comparable] struct {
	// contains filtered or unexported fields
}

Single is a generic type for single value Tag.

func NewSingle added in v0.5.0 

func NewSingle[T comparable](
	name string,
	val T,
	kind Kind,
	strValuer func(T) string,
	sqlValuer func(T) (driver.Value, error),
) *Single[T]

NewSingle returns a new instance of Single.

func (*Single[T]) Get added in v0.5.0 

func (tag *Single[T]) Get() T

Get returns the typed tag value.

func (*Single[T]) Set added in v0.5.0 

func (tag *Single[T]) Set(v T)

Set replaces the tag value with v.

func (*Single[T]) String added in v0.5.0 

func (tag *Single[T]) String() string

func (*Single[T]) TagEqual added in v0.5.0 

func (tag *Single[T]) TagEqual(other Tag) bool

func (*Single[T]) TagKind added in v0.5.0 

func (tag *Single[T]) TagKind() Kind

func (*Single[T]) TagName added in v0.5.0 

func (tag *Single[T]) TagName() string

func (*Single[T]) TagSame added in v0.5.0 

func (tag *Single[T]) TagSame(other Tag) bool

func (*Single[T]) TagSet added in v0.5.0 

func (tag *Single[T]) TagSet(v any) error

TagSet sets the tag value from an untyped value. Returns ErrInvType if v cannot be asserted to T.

func (*Single[T]) TagValue added in v0.5.0 

func (tag *Single[T]) TagValue() any

func (*Single[T]) ValidateWith added in v0.5.0 

func (tag *Single[T]) ValidateWith(rule verax.Rule) error

ValidateWith validates the tag value against rule, returning a field error keyed by the tag name on failure.

func (*Single[T]) Value added in v0.5.0 

func (tag *Single[T]) Value() (driver.Value, error)

Value implements driver.Valuer interface. When the type has no sqlValuer defined, then it returns the value directly and never returns an error.

type Slice added in v0.5.0 

type Slice[T comparable] struct {
	// contains filtered or unexported fields
}

Slice is a generic type for multi value Tag.

func NewSlice added in v0.5.0 

func NewSlice[T comparable](
	name string,
	val []T,
	kind Kind,
	strValuer func([]T) string,
	sqlValuer func([]T) (driver.Value, error),
) *Slice[T]

NewSlice returns a new instance of Slice.

func (*Slice[T]) Get added in v0.5.0 

func (tag *Slice[T]) Get() []T

Get returns the typed tag value slice.

func (*Slice[T]) Set added in v0.5.0 

func (tag *Slice[T]) Set(v []T)

Set replaces the tag value with v.

func (*Slice[T]) String added in v0.5.0 

func (tag *Slice[T]) String() string

func (*Slice[T]) TagEqual added in v0.5.0 

func (tag *Slice[T]) TagEqual(other Tag) bool

func (*Slice[T]) TagKind added in v0.5.0 

func (tag *Slice[T]) TagKind() Kind

func (*Slice[T]) TagName added in v0.5.0 

func (tag *Slice[T]) TagName() string

func (*Slice[T]) TagSame added in v0.5.0 

func (tag *Slice[T]) TagSame(other Tag) bool

func (*Slice[T]) TagSet added in v0.5.0 

func (tag *Slice[T]) TagSet(v any) error

TagSet sets the tag value from an untyped value. Returns ErrInvType if v cannot be asserted to []T.

func (*Slice[T]) TagValue added in v0.5.0 

func (tag *Slice[T]) TagValue() any

func (*Slice[T]) ValidateWith added in v0.5.0 

func (tag *Slice[T]) ValidateWith(rule verax.Rule) error

ValidateWith validates the tag value against rule, returning a field error keyed by the tag name on failure.

func (*Slice[T]) Value added in v0.5.0 

func (tag *Slice[T]) Value() (driver.Value, error)

type Tag 

type Tag interface {
	// TagName returns tag name.
	TagName() string

	// TagKind returns the [Kind] holding the information about the type of
	// the tag value. Use it to interpret the value returned by the
	// [Tag.TagValue] method.
	TagKind() Kind

	// TagValue returns tag value.
	// You may use the value returned by the [Tag.Kind] method
	// to cast it to the proper type.
	TagValue() any
}

Tag is an interface representing a tag.

Tags are named and typed values that can be used to annotate objects.

func TagParserNotImpl added in v0.5.0 

func TagParserNotImpl(name, _ string, _ ...Option) (Tag, error)

TagParserNotImpl returns an error indicating that the tag parser is not implemented.

type TagSet 

type TagSet struct {
	// contains filtered or unexported fields
}

TagSet represents a set of tags.

Example 
package main

import (
	"fmt"

	"github.com/ctx42/nomix/pkg/nomix"
	"github.com/ctx42/nomix/pkg/xtag"
)

func main() {
	set := nomix.NewTagSet()

	set.TagSet(
		xtag.NewInt("A", 42),
		xtag.NewBool("B", true),
		xtag.NewString("C", "foo"),
	)

	fmt.Printf("There are %d tags in the set:\n", set.TagCount())
	fmt.Printf("- A: %v\n", set.TagGet("A").TagValue())
	fmt.Printf("- B: %v\n", set.TagGet("B").TagValue())
	fmt.Printf("- C: %v\n", set.TagGet("C").TagValue())
	fmt.Printf("- D: %v\n", set.TagGet("D"))

}

Output:
There are 3 tags in the set:
- A: 42
- B: true
- C: foo
- D: <nil>

func NewTagSet 

func NewTagSet(opts ...Option) TagSet

NewTagSet returns a new instance of TagSet.

func (TagSet) MetaGetAll 

func (set TagSet) MetaGetAll() map[string]any

func (TagSet) TagCount 

func (set TagSet) TagCount() int

TagCount returns the number of entries in the tag set.

func (TagSet) TagDelete 

func (set TagSet) TagDelete(name string)

func (TagSet) TagDeleteAll 

func (set TagSet) TagDeleteAll()

TagDeleteAll deletes all tags from the set.

func (TagSet) TagGet 

func (set TagSet) TagGet(name string) Tag

func (TagSet) TagGetAll 

func (set TagSet) TagGetAll() map[string]Tag

func (TagSet) TagSet 

func (set TagSet) TagSet(tags ...Tag)

type Tagger 

type Tagger interface {
	// TagGet retrieves from the set a [Tag] by its name. If the name doesn't
	// exist in the set, it returns nil.
	TagGet(name string) Tag

	// TagSet adds instances of [Tag] to the set. If the tag name already
	// exists in the set, it will be overwritten. The nil instances are ignored.
	TagSet(tag ...Tag)

	// TagDelete removes from the set the [Tag] by name. If the name does not
	// exist, the method has no effect.
	TagDelete(name string)
}

Tagger is an interface for managing a collection of distinctly named Tag instances (set). The implementations must not allow for nil values to be stored in the set.

type ValueComparer added in v0.5.0 

type ValueComparer interface {
	// TagEqual returns true if both tags are having the same kind and value.
	TagEqual(other Tag) bool
}

ValueComparer is an interface for comparing tag values.

Source Files

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