dropsgen

Overview ¶

dropsgen generates zero-reflection bind / scan helpers for structs tagged as drops entities.

Usage:

go install github.com/bernardoforcillo/drops/cmd/dropsgen@latest

//go:generate dropsgen -file users.go

dropsgen scans the input file for struct types whose doc comment contains a `//drops:entity` directive. For each match it emits `<input>_drops_gen.go` next to the source, containing:

• bind<Type>(*Type) []any — extracts field values in declared column order, ready to pass to an INSERT or UPDATE.
• scan<Type>(drops.Rows, *Type) error — scans the next row into the struct without reflection.
• cols<Type>() []string — the column names in the order bind / scan use.

The directive accepts a "table" key naming the *pg.Table variable the entity is bound to. The generator does not resolve column metadata at parse time — it derives it from struct tags (`drop:`). At runtime the generated code references the table variable so imports and identifiers stay correct.

//drops:entity table=Users
type User struct {
    ID    int64  `drop:"id"`
    Name  string `drop:"name"`
    Email string `drop:"email"`
}

Polymorphism, relations, and validation are intentionally out of scope for the first iteration — the generator focuses on the hot row-binding path that benefits most from skipping reflection.