Composable validation for Go with fluent builders, rule tags, struct validation, and optional message translation.

• github.com/aatuh/validate/v3: main API (Validate, builders, FromTag)
• github.com/aatuh/validate/v3/core: generic validation engine (unified, cache-optimized)
• github.com/aatuh/validate/v3/glue: integration layer with builders
• github.com/aatuh/validate/v3/validators: type-specific rules
• github.com/aatuh/validate/v3/errors: error types and codes
• github.com/aatuh/validate/v3/structvalidator: struct validation
• github.com/aatuh/validate/v3/translator: i18n helpers

The package is architecturally separated into:

• Core: Generic validation engine, type-agnostic, with unified caching
• Glue: Integration layer that connects core with type-specific builders
• Validators: Type-specific validation implementations

For examples, see the examples package.

Run examples:

# Run all examples in learning order
go test ./examples -v -count 1

# Run specific examples
go test ./examples -v -count 1 -run Test_structTags

Plugin rules that operate on strings (imported by default):

• uuid: validates canonical UUID string
• ulid: validates ULID string
• email: validates email address string

Note on plugin registration:

• validate.New() already registers these plugin validators via blank imports inside the root package.
• If you use core/glue directly, blank-import the plugins yourself:

import (
    _ "github.com/aatuh/validate/v3/validators/email"
    _ "github.com/aatuh/validate/v3/validators/ulid"
    _ "github.com/aatuh/validate/v3/validators/uuid"
)

Tags can be used in struct field tags or with FromTag.

Notes:

• oneof supports comma or space separated values.
• Regex is made safe (anchors added, input length capped).

Use int64;... to require exactly int64 at validation time; int;... accepts any Go int type (int, int8, int16, int32, int64, and unsigned variants for base type checks).

Example: slice;min=1;foreach=(string;min=2).

Stable constants for programmatic handling (see errors/codes.go):

const (
    // String
    CodeStringMin = "string.min"
    CodeStringMax = "string.max"
    CodeStringNonEmpty = "string.nonempty"
    CodeStringPattern = "string.pattern"
    CodeStringOneOf = "string.oneof"

    // Number (ints/floats)
    CodeNumberMin = "number.min"
    CodeNumberMax = "number.max"

    // Slice
    CodeSliceMin = "slice.min"
    CodeSliceMax = "slice.max"
)