package interpolate

import "github.com/mfridman/interpolate"

Index ¶

• func Identifiers(str string) ([]string, error)
• func Interpolate(env Env, str string) (string, error)
• type EmptyValueExpansion
• func (e EmptyValueExpansion) Expand(env Env) (string, error)
• func (e EmptyValueExpansion) Identifiers() []string
• type Env
• func NewMapEnv(env map[string]string) Env
• func NewSliceEnv(env []string) Env
• type Expansion
• type Expression
• func (e Expression) Expand(env Env) (string, error)
• func (e Expression) Identifiers() []string
• type ExpressionItem
• func (i ExpressionItem) String() string
• type Parser
• func NewParser(str string) *Parser
• func (p *Parser) Parse() (Expression, error)
• type RequiredExpansion
• func (e RequiredExpansion) Expand(env Env) (string, error)
• func (e RequiredExpansion) Identifiers() []string
• type SubstringExpansion
• func (e SubstringExpansion) Expand(env Env) (string, error)
• func (e SubstringExpansion) Identifiers() []string
• type UnsetValueExpansion
• func (e UnsetValueExpansion) Expand(env Env) (string, error)
• func (e UnsetValueExpansion) Identifiers() []string
• type VariableExpansion
• func (e VariableExpansion) Expand(env Env) (string, error)
• func (e VariableExpansion) Identifiers() []string

Examples ¶

• Interpolate

Functions ¶

func Identifiers ¶

func Identifiers(str string) ([]string, error)

Indentifiers parses the identifiers from any expansions in the provided string

func Interpolate ¶

func Interpolate(env Env, str string) (string, error)

Interpolate takes a set of environment and interpolates it into the provided string using shell script expansions

package main

import (
	"fmt"
	"log"

	"github.com/mfridman/interpolate"
)

func main() {
	env := interpolate.NewSliceEnv([]string{
		"NAME=James",
	})

	output, err := interpolate.Interpolate(env, "Hello... ${NAME} welcome to the ${ANOTHER_VAR:-🏖}")
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(output)

}

Hello... James welcome to the 🏖

Types ¶

type EmptyValueExpansion ¶

type EmptyValueExpansion struct {
	Identifier string
	Content    Expression
}

EmptyValueExpansion returns either the value of an env, or a default value if it's unset or null

func (EmptyValueExpansion) Expand ¶

func (e EmptyValueExpansion) Expand(env Env) (string, error)

func (EmptyValueExpansion) Identifiers ¶

func (e EmptyValueExpansion) Identifiers() []string

type Env ¶

type Env interface {
	Get(key string) (string, bool)
}

Env is an interface for getting environment variables by name and returning a boolean indicating whether the variable was found.

func NewMapEnv ¶

func NewMapEnv(env map[string]string) Env

NewMapEnv creates an Env from a map of environment variables.

func NewSliceEnv ¶

func NewSliceEnv(env []string) Env

NewSliceEnv creates an Env from a slice of environment variables in the form "key=value".

This can be used with os.Environ to create an Env.

type Expansion ¶

type Expansion interface {
	Expand(env Env) (string, error)
	Identifiers() []string
}

An expansion is something that takes in ENV and returns a string or an error

type Expression ¶

type Expression []ExpressionItem

Expression is a collection of either Text or Expansions

func (Expression) Expand ¶

func (e Expression) Expand(env Env) (string, error)

func (Expression) Identifiers ¶

func (e Expression) Identifiers() []string

type ExpressionItem ¶

type ExpressionItem struct {
	Text string
	// -- or --
	Expansion Expansion
}

ExpressionItem models either an Expansion or Text. Either/Or, never both.

func (ExpressionItem) String ¶

func (i ExpressionItem) String() string

type Parser ¶

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

Parser takes a string and parses out a tree of structs that represent text and Expansions

func NewParser ¶

func NewParser(str string) *Parser

NewParser returns a new instance of a Parser

func (*Parser) Parse ¶

func (p *Parser) Parse() (Expression, error)

Parse expansions out of the internal text and return them as a tree of Expressions

type RequiredExpansion ¶

type RequiredExpansion struct {
	Identifier string
	Message    Expression
}

RequiredExpansion returns an env value, or an error if it is unset

func (RequiredExpansion) Expand ¶

func (e RequiredExpansion) Expand(env Env) (string, error)

func (RequiredExpansion) Identifiers ¶

func (e RequiredExpansion) Identifiers() []string

type SubstringExpansion ¶

type SubstringExpansion struct {
	Identifier string
	Offset     int
	Length     int
	HasLength  bool
}

SubstringExpansion returns a substring (or slice) of the env

func (SubstringExpansion) Expand ¶

func (e SubstringExpansion) Expand(env Env) (string, error)

func (SubstringExpansion) Identifiers ¶

func (e SubstringExpansion) Identifiers() []string

type UnsetValueExpansion ¶

type UnsetValueExpansion struct {
	Identifier string
	Content    Expression
}

UnsetValueExpansion returns either the value of an env, or a default value if it's unset

func (UnsetValueExpansion) Expand ¶

func (e UnsetValueExpansion) Expand(env Env) (string, error)

func (UnsetValueExpansion) Identifiers ¶

func (e UnsetValueExpansion) Identifiers() []string

type VariableExpansion ¶

type VariableExpansion struct {
	Identifier string
}

VariableExpansion represents either $VAR or ${VAR}, our simplest expansion

func (VariableExpansion) Expand ¶

func (e VariableExpansion) Expand(env Env) (string, error)

func (VariableExpansion) Identifiers ¶

func (e VariableExpansion) Identifiers() []string

Source Files ¶

env.go interpolate.go parser.go