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
func main() {
a := []float64{1, 2, 3.4}
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+.
All Go features (not including cgo
) will be supported.
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)
Be interested in how it works? See Import Go packages in Go+ programs.
Also, all Go+ packages can be converted into Go packages and imported in Go programs.
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:
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 compile this example?
gop go tutorial/ # Convert all Go+ packages in tutorial/ into Go packages
go install ./...
Or:
gop install ./... # Convert Go+ packages and go install ./...
Go tutorial/14-Using-goplus-in-Go to get the source code.
Playground based on Docker:
Playground based on GopherJS:
See https://github.com/goplus/gop/tree/master/tutorial
git clone git@github.com:goplus/gop.git
cd gop
go install -v ./...
Go+ supports bytecode backend and Go code generation.
When we use gop go
or gop install
command, it generates Go code to covert Go+ package into Go packages.
When we use gop run
command, it doesn't call go run
command. It generates bytecode to execute.
gop run # Run a Go+ program
gop repl # Run Go+ in REPL/Console mode
gop go [-test] # Convert Go+ packages into Go packages. If -test specified, it tests related packages.
gop fmt # Format Go+ packages
gop export # Export Go packages for Go+ programs
See https://github.com/goplus/gop/wiki/Commands for details.
Note:
gop go -test <gopSrcDir>
converts Go+ packages into Go packages, and for every package, it callgo run <gopPkgDir>/gop_autogen.go
andgop run -quiet <gopPkgDir>
to compare their outputs. If their outputs aren't equal, the test case fails.
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.
a := 1r << 65 // bigint, large than int64
b := 4/5r // bigrat
c := b - 1/3r + 3 * 1/2r
println(a, b, c)
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{}
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{}
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}
sum := 0
for x <- [1, 3, 5, 7, 11, 13, 17], x > 3 {
sum += x
}
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.
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.
You can use Go+ programs as shell scripts now. For example:
#!/usr/bin/env qrun
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.
All Go features (not including cgo
) will be supported.
The Go+ project welcomes all contributors. We appreciate your help!
Here are list of Go+ Contributors. We award an email account (XXX@goplus.org) for every contributor. And we suggest you commit code by using this email account:
git config --global user.email XXX@goplus.org
If you did this, remember to add your XXX@goplus.org
email to https://github.com/settings/emails.
What does a contributor to Go+
mean? He 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?