context

README

tinywasm/context

Minimalist context library for TinyGo.

Features

• No Maps: Uses a fixed array of structs to avoid dynamic allocations.
• Mutable: Supports in-place modification via Set(key, value).
• Minimal Footprint: Designed to keep binary size at a minimum.
• TinyGo Compatible: Fully compatible with TinyGo and WASM environments.
• Fixed Capacity: Maximum of 16 key-value pairs (prioritizes latest values).

Installation

go get github.com/tinywasm/context

Usage

import "github.com/tinywasm/context"

// Create background context
ctx := context.Background()

// Add values (Keys and Values must be strings)
// In-place mutation (simpler for state machines):
_ = ctx.Set("user_id", "123")

// Nested creation (traditional style):
ctx, _ = context.WithValue(ctx, "role", "admin")

// Retrieve values
user := ctx.Value("user_id") // returns "123"
role := ctx.Value("role")    // returns "admin"
missing := ctx.Value("none") // returns ""

// Inspect keys
keys := ctx.Keys()           // returns []string{"user_id", "role"}

Constraints

• Keys and Values are restricted to string type for performance and simplicity.
• Maximum capacity of 16 key-value pairs. Exceeding this will return an error (see fmt error pattern).

Documentation

Index

• type Context
  • func Background() *Context
  • func WithValue(parent *Context, key, value string) (*Context, error)
  • func (c *Context) Keys() []string
  • func (c *Context) Set(key, value string) error
  • func (c *Context) Value(key string) string

Types

type Context

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

Context is a minimalist context compatible with TinyGo. No maps, no channels, uses a fixed array of 16 key-value pairs.

func Background

func Background() *Context

Background returns an empty Context (equivalent to context.Background).

func WithValue

func WithValue(parent *Context, key, value string) (*Context, error)

WithValue creates a new Context with the additional key-value pair. Returns errCapacityExceeded if the capacity of 16 pairs is exceeded.

func (*Context) Keys

func (c *Context) Keys() []string

Keys returns a slice containing all keys in the context. Later values with duplicate keys are not deduplicated - all keys are returned.

func (*Context) Set

func (c *Context) Set(key, value string) error

Set adds or updates a key-value pair in-place. Returns an error if the capacity of 16 pairs is exceeded.

func (*Context) Value

func (c *Context) Value(key string) string

Value searches for the value associated with key (reverse search to prioritize latest values).