Embedding Ring in Ring¶

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

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 environment
                ring_state_runcode(pState,"
                        new qWidget {
                                pObject = x
                                setwindowtitle('Message from the Sub Ring Environment')
                        }
                ")
        ring_state_delete(pState)

ring_state_new() and ring_state_mainfile()¶

Using ring_state_new() and ring_state_mainfile() we can run Ring programs from Ring programs

But unlike ring_state_main(), Here we can control when to delete the Ring state!

This is important when we run GUI programs from GUI programs

Because they will share the GUI Library (RingQt), And In this case the caller will call

qApp.Exec()

So the sub program, will not stop and will return to the Main program

Here deleting the State of the sub programs will lead to a problem when we run the sub program events

So keeping the state is important for sub GUI programs hosted in GUI programs.

Example:

load "guilib.ring"

func main
        new qApp {
                win = new qWidget() {
                        setWindowTitle("Test ring_state_mainfile()")
                        resize(400,400) move(100,100)
                        btn = new qPushButton(Win) {
                                settext("test")
                                setclickevent("mytest()")
                        }
                        show()
                }
                exec()
        }

func mytest
        pState = ring_state_new()
        ring_state_mainfile(pState,"runprogram.ring")
        # Here we don't delete the state if we will run GUI application
        # So we can run the GUI application events
                // ring_state_delete(pState)

If you will use this feature, remember to update the previous example based on your application needs

So you can call ring_state_delete() at some point to avoid the memory leak!

Runtime Errors when Embedding Ring in Ring¶

Starting from Ring 1.8

When embedding Ring in Ring, the error in the hosted environment will not close the host

Example:

? "Start the test!"

pState = ring_state_init()

ring_state_runcode(pState," ? 'Let us try having an error' ? x")

ring_state_delete(pState)

? ""
? "End of test!"

Output:

Start the test!
Let us try having an error

Line 1 Error (R24) : Using uninitialized variable : x
in file Ring_EmbeddedCode
End of test!

ring_state_filetokens() function¶

Starting from Ring 1.12 we have the ring_state_filetokens() function

Using this function we can get all the tokens in the ring source code file.

C_FILENAME      = "test_tokens.ring"
C_WIDTH         = 12

# write the file
        write(C_FILENAME,'
                        see "Hello, World!"
                        ? 3*2+3
                        Name = "Ring"
                        ? Name
')

# Token Type
        C_KEYWORD       = 0
        C_OPERATOR      = 1
        C_LITERAL       = 2
        C_NUMBER        = 3
        C_IDENTIFIER    = 4
        C_ENDLINE       = 5

# Keywords List
aKEYWORDS = ["IF","TO","OR","AND","NOT","FOR","NEW","FUNC",
"FROM","NEXT","LOAD","ELSE","SEE","WHILE","OK","CLASS","RETURN","BUT",
"END","GIVE","BYE","EXIT","TRY","CATCH","DONE","SWITCH","ON","OTHER","OFF",
"IN","LOOP","PACKAGE","IMPORT","PRIVATE","STEP","DO","AGAIN","CALL","ELSEIF",
"PUT","GET","CASE","DEF","ENDFUNC","ENDCLASS","ENDPACKAGE",
"CHANGERINGKEYWORD","CHANGERINGOPERATOR","LOADSYNTAX"]

pState = ring_state_new()
aList = ring_state_filetokens(pState,C_FILENAME)
PrintTokens(aList)
ring_state_delete(pState)

func PrintTokens aList
        for aToken in aList
                switch aToken[1]
                on C_KEYWORD
                        ? Width("Keyword",C_WIDTH) + ": "  + aKeywords[0+aToken[2]]
                on C_OPERATOR
                        ? Width("Operator",C_WIDTH)  + ": " + aToken[2]
                on C_LITERAL
                        ? Width("Literal",C_WIDTH)  + ": " + aToken[2]
                on C_NUMBER
                        ? Width("Number",C_WIDTH)  + ": " + aToken[2]
                on C_IDENTIFIER
                        ? Width("Identifier",C_WIDTH)  + ": " + aToken[2]
                on C_ENDLINE
                        ? "EndLine"
                off
        next

func Width cText,nWidth
        return cText+copy(" ",nWidth-len(cText))

Output:

EndLine
Keyword     : SEE
Literal     : Hello, World!
EndLine
Operator    : ?
Number      : 3
Operator    : *
Number      : 2
Operator    : +
Number      : 3
EndLine
Identifier  : name
Operator    : =
Literal     : Ring
EndLine
Operator    : ?
Identifier  : name
EndLine

Embedding Ring in Ring¶