eval

package

v0.0.0-...-5b51d85 Latest Latest Go to latest Published: Mar 7, 2024 License: MIT Imports: 6 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

gitlab.com/luyang93/The-Go-Programming-Language

Links

Open Source Insights

README ¶

Exercise 7.14 (P205)

Define a new concrete type that satisfies the Expr interface and provides a new operation such as computing the minimum value of its operands. Since the Parse function does not create instances of this new type, to use it you will need to construct a syntax tree directly (or extend the parser).

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
	// String returns a human readable string of the Expr
	String() string
}

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) 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