Embedding Ring in Ring

In this chapter we will learn about embedding Ring in Ring programs and applications.

Embedding Ring in Ring without sharing the State

From Ring 1.0 we already have functions for embedding Ring in the C language. Also we can execute Ring code inside Ring programs using the eval() function. In this release we provide functions for embedding Ring in Ring programs without sharing the state.

Advantages:

1. Quick integration for Ring programs and applications together without conflicts.
2. Execute and run Ring code in safe environments that we can trace.

Example:

pState = ring_state_init()
ring_state_runcode(pState,"See 'Hello, World!'+nl")
ring_state_runcode(pState,"x = 10")

pState2 = ring_state_init()
ring_state_runcode(pState2,"See 'Hello, World!'+nl")
ring_state_runcode(pState2,"x = 20")

ring_state_runcode(pState,"see x +nl")
ring_state_runcode(pState2,"see x +nl")

v1 = ring_state_findvar(pState,"x")
v2 = ring_state_findvar(pState2,"x")

see v1[3] + nl
see V2[3] + nl

ring_state_delete(pState)
ring_state_delete(pState2)

Output:

Hello, World!
Hello, World!
10
20
10
20

Serial Execution of Programs

We can execute application after another application using ring_state_main()

Example:

chdir(exefolder()+"/../applications/formdesigner")
ring_state_main('formdesigner.ring')
chdir(exefolder()+"/../applications/cards")
ring_state_main('cards.ring')

ring_state_setvar()

Using ring_state_setvar() we can set variables value

The value could be (String, Number, List or C Pointer)

We need this function to quickly pass lists and C pointers to the Sub Ring Environment

Syntax:

ring_state_setvar(oState,cVariableName,Value)

Example:

load "guilib.ring"

myapp   = null
win     = null

func main
        myapp = new qApp {
                win = new qWidget() {
                        setWindowTitle("Advanced Example on using ring_state_setvar()")
                        move(100,100)
                        resize(600,400)
                        new qPushButton(win) {
                                setText("Test")
                                setClickEvent("Test()")
                        }
                        # We need this because using load 'guilib.ring' in the sub environment
                        # Will create timers by Qt and closing the window will not be enough
                        # To close the application
                        oFilter = new qAllEvents(win)
                        oFilter.setCloseEvent("myapp.quit()")
                        win.installeventfilter(oFilter)
                        show()
                }
                exec()
        }

func test
        pState = ring_state_init()
        ring_state_runcode(pstate,"load 'guilib.ring'")
        ring_state_runcode(pState,"x = NULL")
        # Pass String
                ring_state_setvar(pState,"x","hello")
                ring_state_runcode(pState,"? x")
        # Pass Number
                ring_state_setvar(pState,"x",100)
                ring_state_runcode(pState,"? x")
        # Pass List
                ring_state_setvar(pState,"x",["one","two","three"])
                ring_state_runcode(pState,"? x")
        # Pass Object
        # We can't pass the Ring Object (win)
        # Because Objects store pointers to the Class Information
        # And the class is related to the Parent Ring Environment
        # And the sub Ring environment can't access it
        # But we can pass C pointers like win.pObject
                ring_state_setvar(pState,"x",win.pObject)
        # Now we create the object again but using the same C pointer
        # So we have access to the Same window in the parent Ring enviroment
                ring_state_runcode(pState,"
                        new qWidget {
                                pObject = x
                                setwindowtitle('Message from the Sub Ring Environment')
                        }
                ")
        ring_state_delete(pState)