The Go+ language for engineering, STEM education, and data science
Summary about Go+
What are mainly impressions about Go+?
- A static typed language.
- Fully compatible with the Go language.
- Script-like style, and more readable code for data science than Go.
For example, the following is legal Go+ source code:
a := [1, 2, 3.4]
println(a)
How do we do this in the Go language?
package main
import "fmt"
func main() {
a := []float64{1, 2, 3.4}
fmt.Println(a)
}
Of course, we don't only do less-typing things.
For example, we support list comprehension, which makes data processing easier.
a := [1, 3, 5, 7, 11]
b := [x*x for x <- a, x > 3]
println(b) // output: [25 49 121]
mapData := {"Hi": 1, "Hello": 2, "Go+": 3}
reversedMap := {v: k for k, v <- mapData}
println(reversedMap) // output: map[1:Hi 2:Hello 3:Go+]
We will keep Go+ simple. This is why we call it Go+, not Go++.
Less is exponentially more.
It's for Go, and it's also for Go+.
Compatibility with Go
All Go features will be supported (including partially support cgo, see below).
All Go packages (even these packages use cgo) can be imported by Go+.
import (
"fmt"
"strings"
)
x := strings.NewReplacer("?", "!").Replace("hello, world???")
fmt.Println("x:", x)
And all Go+ packages can also be imported in Go programs. What you need to do is just using gop command instead of go.
First, let's make a directory named tutorial/14-Using-goplus-in-Go.
Then write a Go+ package named foo in it:
package foo
func ReverseMap(m map[string]int) map[int]string {
return {v: k for k, v <- m}
}
Then use it in a Go package (14-Using-goplus-in-Go/gomain):
package main
import (
"fmt"
"github.com/goplus/gop/tutorial/14-Using-goplus-in-Go/foo"
)
func main() {
rmap := foo.ReverseMap(map[string]int{"Hi": 1, "Hello": 2})
fmt.Println(rmap)
}
How to build this example? You can use:
gop install -v ./...
or:
gop run tutorial/14-Using-goplus-in-Go/gomain
Go tutorial/14-Using-goplus-in-Go to get the source code.
Playground
Go+ Playground based on Docker:
Go+ Playground based on GopherJS (currently only available in v0.7.x):
Go+ Jupyter kernel:
Tutorials
See https://github.com/goplus/gop/tree/main/tutorial
How to build
git clone [email protected]:goplus/gop.git
cd gop
./all.bash
Bytecode vs. Go code
Go+ supports bytecode backend and Go code generation.
When we use gop command, it generates Go code to covert Go+ package into Go packages.
gop run # Run a Go+ program
gop install # Build Go+ files and install target to GOBIN
gop build # Build Go+ files
gop test # Test Go+ packages
gop fmt # Format Go+ packages
gop clean # Clean all Go+ auto generated files
gop go # Convert Go+ packages into Go packages
When we use igop command, it generates bytecode to execute.
igop # Run a Go+ program
In bytecode mode, Go+ doesn't support cgo. However, in Go-code-generation mode, Go+ fully supports cgo.
Go+ features
Rational number: bigint, bigrat, bigfloat
We introduce the rational number as native Go+ types. We use suffix r to denote rational literals. For example, (1r << 200) means a big int whose value is equal to 2200. And 4/5r means the rational constant 4/5.
var a bigint = 1r << 65 // bigint, large than int64
var b bigrat = 4/5r // bigrat
c := b - 1/3r + 3 * 1/2r // bigrat
println(a, b, c)
var x *big.Int = 1r << 65 // (1r << 65) is untyped bigint, and can be assigned to *big.Int
var y *big.Rat = 4/5r
println(x, y)
Map literal
x := {"Hello": 1, "xsw": 3.4} // map[string]float64
y := {"Hello": 1, "xsw": "Go+"} // map[string]interface{}
z := {"Hello": 1, "xsw": 3} // map[string]int
empty := {} // map[string]interface{}
Slice literal
x := [1, 3.4] // []float64
y := [1] // []int
z := [1+2i, "xsw"] // []interface{}
a := [1, 3.4, 3+4i] // []complex128
b := [5+6i] // []complex128
c := ["xsw", 3] // []interface{}
empty := [] // []interface{}
Deduce struct type
type Config struct {
Dir string
Level int
}
func foo(conf *Config) {
// ...
}
foo({Dir: "/foo/bar", Level: 1})
Here foo({Dir: "/foo/bar", Level: 1}) is equivalent to foo(&Config{Dir: "/foo/bar", Level: 1}). However, you can't replace foo(&Config{"/foo/bar", 1}) with foo({"/foo/bar", 1}), because it is confusing to consider {"/foo/bar", 1} as a struct literal.
You also can omit struct types in a return statement. For example:
type Result struct {
Text string
}
func foo() *Result {
return {Text: "Hi, Go+"} // return &Result{Text: "Hi, Go+"}
}
List comprehension
a := [x*x for x <- [1, 3, 5, 7, 11]]
b := [x*x for x <- [1, 3, 5, 7, 11], x > 3]
c := [i+v for i, v <- [1, 3, 5, 7, 11], i%2 == 1]
d := [k+","+s for k, s <- {"Hello": "xsw", "Hi": "Go+"}]
arr := [1, 2, 3, 4, 5, 6]
e := [[a, b] for a <- arr, a < b for b <- arr, b > 2]
x := {x: i for i, x <- [1, 3, 5, 7, 11]}
y := {x: i for i, x <- [1, 3, 5, 7, 11], i%2 == 1}
z := {v: k for k, v <- {1: "Hello", 3: "Hi", 5: "xsw", 7: "Go+"}, k > 3}
Select data from a collection
type student struct {
name string
score int
}
students := [student{"Ken", 90}, student{"Jason", 80}, student{"Lily", 85}]
unknownScore, ok := {x.score for x <- students, x.name == "Unknown"}
jasonScore := {x.score for x <- students, x.name == "Jason"}
println(unknownScore, ok) // output: 0 false
println(jasonScore) // output: 80
Check if data exists in a collection
type student struct {
name string
score int
}
students := [student{"Ken", 90}, student{"Jason", 80}, student{"Lily", 85}]
hasJason := {for x <- students, x.name == "Jason"} // is any student named Jason?
hasFailed := {for x <- students, x.score < 60} // is any student failed?
For loop
sum := 0
for x <- [1, 3, 5, 7, 11, 13, 17], x > 3 {
sum += x
}
For range of UDT
type Foo struct {
}
// Gop_Enum(proc func(val ValType)) or:
// Gop_Enum(proc func(key KeyType, val ValType))
func (p *Foo) Gop_Enum(proc func(key int, val string)) {
// ...
}
foo := &Foo{}
for k, v := range foo {
println(k, v)
}
for k, v <- foo {
println(k, v)
}
println({v: k for k, v <- foo})
Note: you can't use break/continue or return statements in for range of udt.Gop_Enum(callback).
For range of UDT2
type FooIter struct {
}
// (Iterator) Next() (val ValType, ok bool) or:
// (Iterator) Next() (key KeyType, val ValType, ok bool)
func (p *FooIter) Next() (key int, val string, ok bool) {
// ...
}
type Foo struct {
}
// Gop_Enum() Iterator
func (p *Foo) Gop_Enum() *FooIter {
// ...
}
foo := &Foo{}
for k, v := range foo {
println(k, v)
}
for k, v <- foo {
println(k, v)
}
println({v: k for k, v <- foo})
Lambda expression
func plot(fn func(x float64) float64) {
// ...
}
func plot2(fn func(x float64) (float64, float64)) {
// ...
}
plot(x => x * x) // plot(func(x float64) float64 { return x * x })
plot2(x => (x * x, x + x)) // plot2(func(x float64) (float64, float64) { return x * x, x + x })
Overload operators
import "math/big"
type MyBigInt struct {
*big.Int
}
func Int(v *big.Int) MyBigInt {
return MyBigInt{v}
}
func (a MyBigInt) + (b MyBigInt) MyBigInt { // binary operator
return MyBigInt{new(big.Int).Add(a.Int, b.Int)}
}
func (a MyBigInt) += (b MyBigInt) {
a.Int.Add(a.Int, b.Int)
}
func -(a MyBigInt) MyBigInt { // unary operator
return MyBigInt{new(big.Int).Neg(a.Int)}
}
a := Int(1r)
a += Int(2r)
println(a + Int(3r))
println(-a)
Error handling
We reinvent the error handling specification in Go+. We call them ErrWrap expressions:
expr! // panic if err
expr? // return if err
expr?:defval // use defval if err
How to use them? Here is an example:
import (
"strconv"
)
func add(x, y string) (int, error) {
return strconv.Atoi(x)? + strconv.Atoi(y)?, nil
}
func addSafe(x, y string) int {
return strconv.Atoi(x)?:0 + strconv.Atoi(y)?:0
}
println(`add("100", "23"):`, add("100", "23")!)
sum, err := add("10", "abc")
println(`add("10", "abc"):`, sum, err)
println(`addSafe("10", "abc"):`, addSafe("10", "abc"))
The output of this example is:
add("100", "23"): 123
add("10", "abc"): 0 strconv.Atoi: parsing "abc": invalid syntax
===> errors stack:
main.add("10", "abc")
/Users/xsw/goplus/tutorial/15-ErrWrap/err_wrap.gop:6 strconv.Atoi(y)?
addSafe("10", "abc"): 10
Compared to corresponding Go code, It is clear and more readable.
And the most interesting thing is, the return error contains the full error stack. When we got an error, it is very easy to position what the root cause is.
How these ErrWrap expressions work? See Error Handling for more information.
Auto property
Let's see an example written in Go+:
import "github.com/goplus/gop/ast/goptest"
doc := goptest.New(`... Go+ code ...`)!
println(doc.Any().FuncDecl().Name())
In many languages, there is a concept named property who has get and set methods.
Suppose we have get property, the above example will be:
import "github.com/goplus/gop/ast/goptest"
doc := goptest.New(`... Go+ code ...`)!
println(doc.any.funcDecl.name)
In Go+, we introduce a concept named auto property. It is a get property, but is implemented automatically. If we have a method named Bar(), then we will have a get property named bar at the same time.
Unix shebang
You can use Go+ programs as shell scripts now. For example:
#!/usr/bin/env -S gop run
println("Hello, Go+")
println(1r << 129)
println(1/3r + 2/7r*2)
arr := [1, 3, 5, 7, 11, 13, 17, 19]
println(arr)
println([x*x for x <- arr, x > 3])
m := {"Hi": 1, "Go+": 2}
println(m)
println({v: k for k, v <- m})
println([k for k, _ <- m])
println([v for v <- m])
Go tutorial/20-Unix-Shebang/shebang to get the source code.
Go features
All Go features (including partially support cgo) will be supported. In bytecode mode, Go+ doesn't support cgo. However, in Go-code-generation mode, Go+ fully supports cgo.
IDE Plugins
Contributing
The Go+ project welcomes all contributors. We appreciate your help!
Here are list of Go+ Contributors. We award an email account ([email protected]) for every contributor. And we suggest you commit code by using this email account:
git config --global user.email [email protected]
If you did this, remember to add your [email protected] email to https://github.com/settings/emails.
What does a contributor to Go+ mean? You must meet one of the following conditions:
- At least one pull request of a full-featured implemention.
- At least three pull requests of feature enhancements.
- At least ten pull requests of any kind issues.
Where can you start?
