buffer — a mutable text buffer (StringBuilder)

github.com/go-composites/buffer (Go package Buffer, imported from the src/ sub-directory) is the org's mutable text-buffer composite — a StringBuilder over Go's stdlib strings.Builder. It is the mutable counterpart to the immutable string value composite: where string's value-producing operations each return a new boxed value, a Buffer accumulates text in place. Append, AppendRune and Reset mutate the receiver and return it, so calls chain. It never goes nil: Null() yields a Null-Object Buffer that honours the full Interface.

API

import Buffer "github.com/go-composites/buffer/src"

type Interface interface {
    Append(s string) Interface
    AppendRune(r rune) Interface
    ToGoString() string
    Len() int
    IsEmpty() bool
    Reset() Interface
    IsNull() bool
}

func New() Interface
func From(s string) Interface
func Null() Interface

• New() builds a new, empty Buffer.
• From(s) builds a new Buffer seeded with the initial text s.
• Null() returns the Null-Object buffer (see below).

Member	Behaviour
Append(s)	Writes s to the end of the buffer, mutating it in place, and returns the receiver, so calls chain.
AppendRune(r)	Writes a single rune to the end of the buffer, mutating it in place, and returns the receiver, so calls chain.
ToGoString()	Returns the accumulated text as a Go string.
Len()	Returns the length of the accumulated text in bytes.
IsEmpty()	Returns true when the buffer holds no text.
Reset()	Clears the buffer, mutating it in place, and returns the receiver, so calls chain.
IsNull()	Returns false for a real buffer, true for the Null() one.

Usage

b := Buffer.New().
    Append("Hello").
    Append(", ").
    Append("World").
    AppendRune('!')

fmt.Println(b.ToGoString()) // Hello, World!
fmt.Println(b.Len())        // 13
fmt.Println(b.IsEmpty())    // false

b.Reset() // mutates b in place — now empty
fmt.Println(b.IsEmpty())    // true

// From seeds initial text:
c := Buffer.From("seed")
fmt.Println(c.ToGoString()) // seed

The Null-Object variant

Buffer.Null() honours the full Interface without ever being nil: it holds no text, so its mutators (Append, AppendRune, Reset) are no-ops returning the null buffer, ToGoString() is "", Len() is 0, IsEmpty() is true, and IsNull() returns true.

Dependencies

buffer is self-contained — it wraps the stdlib strings.Builder and has no intra-org dependencies.