A embeded script language interpreter written by Go. The language (FlowScript) is functional.

Usage

Use:

import (
    parser "https://github.com/zhangzheheng12345/flowscript"
) // parser actually contains the whole flowscript interpreter

and add:

require github.com/zhangzheheng12345/flowscript v0.3
replace github.com/zhangzheheng12345/flowscript v0.3 => github.com/zhangzheheng12345/FlowScript v0.3

in go.mod to import it to your Go project.

( I don't know why there must be a replacement on my machine. Who could give me an answer? )

Use:

parser.Global.RunBlock( <your codes(type string)> )

to run FlowScript code in a independent scope which will not influence the outside context. parser.Global is the global context which provides buildin functions.

Use:

parser.AddGoFunc(
  <function name(type string)>,
  <function(type parser.GoFuncForFS, same as func([]interface{}, *parser.Context) interface{})>,
  <number of arguments(type int)(-n => needs at least n-1 arguments )>,
)

to add native Go functions to global scope. Have a look at buildin_funcs.go to learn more about using native Go functions in FlowScript.

Examples

Hello World

echoln "Hello World!" # output: Hello World!

Fibonacci sequence

def fibonacci a b begin
    add a b >> echoln
    smlr (a+b) 1000 > if - begin
        fibonacci b (a+b)
    end
end
echoln "fibonacci begins ..."
fibonacci 1 1

Sum of a list

Of course better and faster to use reduce:

def sum li begin
    lambda total v begin add total v end >> reduce li
end

#test
list 1 2 3 4 >> sum >> echoln

Here is another old-fashioned, slower and more complex version:

def sum li begin
    len li > equal - 0 > if - begin
        expr 0
    end else begin
        len li >> slice li 1 >> sum > index li 0 >> add
    end
end

# test
list 1 2 3 4 >> sum >> echoln

OOP Mock (yes, in a functional language)

def Student name li begin # This function will be used as a constructor
    echoln "constructor called!"
    lambda total v begin add total v end >>
	    reduce li > # calculate sum
        len li >> div > var avg -
    struct begin
        def getName begin expr name end # Returns the name of the student
        def getScore begin expr li end # Returns a list which contains the student's score
        def addScore score begin
            app li score >> Student name # Add a score to the list and returns a new object (FP)
        end
        def avgScore begin expr avg end
    end
end
list 95 96 97 >> Student "Zhang" > var A -
echo "name: "; A.getName >> echoln
echo "score: " ; A.getScore >> echoln
echo "avg: "; A.avgScore >> echoln
echoln "Now the score is updated."
A.addScore 100 > var B -
echo "score: "; B.getScore >> echoln
echo "avg: "; B.avgScore >> echoln