Documentation
¶
Overview ¶
Package ast contains a simple AST for our scripts.
The intention is that the parser will process a list of rules, and will generate a Program which will be executed.
The program will consist of an arbitrary number of assignments, inclusions, and rules.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var FALSE = &Boolean{Value: false}
FALSE is a global false-value, which simplifies our function returns
var FUNCTIONS map[string]BuiltIn
FUNCTIONS contains our list of built-in functions, as a map.
The key is the name of the function, and the value is the pointer to the function which is used to implement it.
var STDIN *bufio.Reader
STDIN is where we read from in our `prompt` function
var TRUE = &Boolean{Value: true}
TRUE is a global true-value, which simplifies our function returns.
Functions ¶
This section is empty.
Types ¶
type Array ¶ added in v0.18.0
type Array struct {
// Object is our parent object.
Object
// Values hold the literal values we contain.
Values []Object
}
Array is a holder which can contain an arbitrary number of any of our primitive types.
NOTE: Arrays cannot be nested, due to our parser-limitations.
func (Array) Evaluate ¶ added in v0.18.0
func (a Array) Evaluate(env *environment.Environment) (string, error)
Evaluate returns the value of the array object.
The evaluation here consists of the joined output of evaluating all the children we contain.
type Assign ¶
type Assign struct {
// Node is our parent object.
Node
// Key is the name of the variable.
Key string
// Value is the value which will be set.
Value Object
// ConditionType holds "if" or "unless" if this assignment
// action is to be carried out conditionally.
ConditionType string
// Function holds a function to call, if this is a conditional
// action.
Function Funcall
}
Assign represents a variable assignment.
type Backtick ¶ added in v0.17.0
type Backtick struct {
// Object is our parent object.
Object
// Value is the command we're to execute.
Value string
}
Backtick is a value which returns the output of executing a command.
func (Backtick) Evaluate ¶ added in v0.17.0
func (b Backtick) Evaluate(env *environment.Environment) (string, error)
Evaluate returns the value of the Backtick object.
type Boolean ¶ added in v0.17.0
type Boolean struct {
// Object is our parent object.
Object
// Value is the literal value we hold
Value bool
}
Boolean represents a true/false value
func (Boolean) Evaluate ¶ added in v0.17.0
func (b Boolean) Evaluate(env *environment.Environment) (string, error)
Evaluate returns the value of the Boolean object.
type BuiltIn ¶ added in v0.17.0
type BuiltIn func(env *environment.Environment, args []string) (Object, error)
BuiltIn is the signature of a built-in function
type Funcall ¶ added in v0.17.0
type Funcall struct {
// Object is our parent object.
Object
// Name is the name of the function to be invoked.
Name string
// Arguments are the arguments to be passed to the call.
Args []Object
}
Funcall represents a function-call.
func (Funcall) Evaluate ¶ added in v0.17.0
func (f Funcall) Evaluate(env *environment.Environment) (string, error)
Evaluate returns the value of the function call.
type Include ¶
type Include struct {
// Node is our parent object.
Node
// Source holds the location to include.
Source Object
// ConditionType holds "if" or "unless" if this inclusion is to
// be executed conditionally.
ConditionType string
// Function holds a function to call, if this is a conditional
// action.
Function Funcall
}
Include represents a file inclusion.
This is produced by the parser by include statements.
type Node ¶
type Node interface {
// String will convert this Node object to a human-readable form.
String() string
}
Node represents a node that we can process.
type Number ¶ added in v0.17.0
type Number struct {
// Object is our parent object.
Object
// Value is the literal number we're holding.
Value int64
}
Number represents an integer/hexadecimal/octal number.
Note that we support integers only, not floating-point numbers.
func (Number) Evaluate ¶ added in v0.17.0
func (n Number) Evaluate(env *environment.Environment) (string, error)
Evaluate returns the value of the Number object.
type Object ¶ added in v0.17.0
type Object interface {
// String returns the object contents as a string
String() string
// Evaluate returns the value of the literal.
//
// The environment is made available because we want to
// allow variable expansion within strings and backticks.
Evaluate(env *environment.Environment) (string, error)
}
Object is an interface which must be implemented by anything which will be used as a core-primitive value.
A primitive can be output as a string, and also self-evaluate to return a string-value.
type Program ¶
type Program struct {
// Recipe contains the list of rule/assignment/include
// statements we're going to process.
Recipe []Node
}
Program contains a program
type Rule ¶
type Rule struct {
// Node is our parent node.
Node
// Type contains the rule-type.
Type string
// Name contains the name of the rule.
Name string
// Triggered is true if this rule is only triggered by
// another rule notifying it.
//
// Triggered rules are ignored when processing our list.
Triggered bool
// Parameters contains the params supplied by the user.
//
// The keys will be strings, with the values being either
// a single ast Node, or an array of them.
//
Params map[string]interface{}
// ConditionType holds "if" or "unless" if this rule should
// be executed only conditionally.
ConditionType string
// Function holds a function to call, if this is a conditional
// action.
Function Funcall
}
Rule represents a parsed rule.
type String ¶ added in v0.17.0
type String struct {
// Object is our parent object.
Object
// Value is the literal string we've got
Value string
}
String represents a string literal
func (String) Evaluate ¶ added in v0.17.0
func (s String) Evaluate(env *environment.Environment) (string, error)
Evaluate returns the value of the String object.
This means expanding the variables contained within the string.
Source Files