eval

package

v0.0.0-...-83015c9 Latest Latest Go to latest Published: Jul 19, 2021 License: GPL-3.0 Imports: 8 Imported by: 0

Details

Valid go.mod file

The Go module system was introduced in Go 1.11 and is the official dependency management solution for Go.
Redistributable license

Redistributable licenses place minimal restrictions on how software can be used, modified, and redistributed.
Tagged version

Modules with tagged versions give importers more predictable builds.
Stable version

When a project reaches major version v1 it is considered stable.
Learn more about best practices

Repository

github.com/jmhal/goprogramming

Documentation ¶

Overview ¶

Package eval provides an expression evaluator.

Index ¶

func Format(e Expr) string
type Env
type Expr
- func Parse(input string) (_ Expr, err error)
type Var

Constants ¶

This section is empty.

Variables ¶

This section is empty.

Functions ¶

func Format ¶

func Format(e Expr) string

Format formats an expression as a string. It does not attempt to remove unnecessary parens.

Types ¶

type Env ¶

type Env map[Var]float64

type Expr ¶

type Expr interface {
	// Eval returns the value of this Expr in the environment env.
	Eval(env Env) float64
	// Check reports errors in this Expr and adds its Vars to the set.
	Check(vars map[Var]bool) error
	// Pretty pink the syntax tree
	String() string
	// Set up Environment
	Environment(env Env) Env
}

An Expr is an arithmetic expression.

func Parse ¶

func Parse(input string) (_ Expr, err error)

Parse parses the input string as an arithmetic expression.

expr = num                         a literal number, e.g., 3.14159
     | id                          a variable name, e.g., x
     | id '(' expr ',' ... ')'     a function call
     | '-' expr                    a unary operator (+-)
     | expr '+' expr               a binary operator (+-*/)

type Var ¶

type Var string

A Var identifies a variable, e.g., x.

func (Var) Check ¶

func (v Var) Check(vars map[Var]bool) error

func (Var) Environment ¶

func (v Var) Environment(env Env) Env

func (Var) Eval ¶

func (v Var) Eval(env Env) float64

func (Var) String ¶

func (v Var) String() string

Source Files ¶

View all Source files

?	: This menu
/	: Search site
f or F	: Jump to
y or Y	: Canonical URL