gofunc

_GOFUNC calls Go function from BASIC code

_GOFUNC() is a BASIC keyword introduced by the 'basgo' compiler in order to call a Go function from BASIC code.

Usage

BASIC code calling Go code:

10 result = _GOFUNC("func_name", arg1, arg2, ..., argN)
20 print result

Go code called from BASIC:

func func_name(arg1, arg2, ..., argN float64) float64
    return some_float64_value
}

Hints

• Append a '$' to _GOFUNC func_name in order to call a string-returning function.

BASIC:

10 result$ = _GOFUNC("func_name$", arg1, arg2, ..., argN)

Go:

func func_name(arg1, arg2, ..., argN float64) string
    return "some_string_value"
}

• Use _GOPROC() to call a Go function with no return value.

Example:

The Go functions:

$ more gofunc.go
package main

import (
        "fmt"
)

func sum(a, b float64) float64 {
        return a + b
}

func concat(a, b string) string {
        return a + b
}

func printString(s string) {
        fmt.Print(s)
}
$

BASIC code using _GOFUNC and _GOPROC to call Go functions:

$ more gofunc.bas
10 print _gofunc("sum", sqr(4+5), 20-10)
20 print _gofunc("concat$", "a", "b")
30 _goproc("printString", "c"): print
$

Compile the BASIC code to Go (a.go) then build it along with the Go functions:

$ basgo-build < gofunc.bas > a.go
$ go run a.go gofunc.go
13
ab
c
$

Defining Go code within BASIC code with _GOIMPORT and _GODECL

_GOFUNC and _GOPROC can call Go function from BASIC. However, how can that Go function be defined? Naturally, the Go function can be defined using a full-Go source file, as depicted in the gofunc.go example above. Another option is to embed the Go code within BASIC code, using _GOIMPORT and _GODECL. In the example rad.bas below, _GOIMPORT includes the Go "math" package, and _GODECL is used to define the Go "degToRad" function. Then, _GOFUNC can be used to call that Go function from BASIC. The _GOIMPORT/_GODECL option is cumbersome for large Go code, but it can be useful for defining small Go functions directly within BASIC code.

$ more gofunc/rad.bas 
110 rem Using _GOIMPORT and _GODECL to embed Go code within BASIC code
120 rem
130 _goimport("math")
140 _godecl("func degToRad(d float64) float64 {")
150 _godecl("    return d*math.Pi/180")
160 _godecl("}")
170 rem
180 rem Now using _GOFUNC to call that Go function from BASIC code
190 rem
200 d = 180
210 r = _gofunc("degToRad", d)
220 print d;"degrees in radians is";r

Running the example:

$ basgo-build < gofunc/rad.bas > a.go && go run a.go
 180 degrees in radians is 3.141592653589793 
$