The Ring programming language version 1.7 book - Part 83 of 196
0 likes20 views
The document describes several low-level functions in Ring that provide access to the virtual machine and runtime environment. These include functions to call the garbage collector, get and set pointers, allocate memory, compare pointers, and get lists of functions, classes, packages, memory scopes, call stacks, and loaded files.
![Ring Documentation, Release 1.7
70.1 callgc() function
Use this function to force calling the garbage collector during function execution when you use a loop that create temp.
variables that you don’t free using the assignment operation.
It’s very rare to need this function but it’s useful when you create something like event-loop for your game engine and
start creating lists on the fly when you call functions.
Example
While True
# process events
# call functions using temp. lists like myfunc(["temp list"])
# call the garbage collector
callgc()
End
Tip: In Ring the garbage collector works automatically in the end of function execution or when you use the assign-
ment statement.
70.2 varptr() function
Use the varptr() function when you need to pass a pointer to a C/C++ function.
Syntax:
varptr(cVariableName,cPointerType) —> Low Level Object (C Pointer)
example:
r = 10
z = 20
see r + nl
see varptr("r","int")
see varptr("z","int")
Output:
10
00E3C740
int
2
00E3BEC0
int
2
Note: the low level object is a list contains three items (The Pointer, The Type, The Status)
70.3 space() function
Use the space function to allocate a specific number of bytes in Memory.
70.1. callgc() function 793](https://image.slidesharecdn.com/821pdfsamfayedringdoc1-180722102939/85/The-Ring-programming-language-version-1-7-book-Part-83-of-196-2-320.jpg)
![Ring Documentation, Release 1.7
• Nested Lists Pointer
• State List
Syntax:
RingVM_CallList() ---> List
Example:
hello()
func hello
test()
func test
mylist = ringvm_calllist()
for t in mylist see t[2] + nl next
Output:
function hello() in file B:/ring/tests/scripts/calllist.ring
called from line 1
function test() in file B:/ring/tests/scripts/calllist.ring
called from line 3
ringvm_calllist
70.14 ringvm_fileslist() function
Function return a list of the Ring Files.
Syntax:
RingVM_FilesList() ---> List
Example:
load "stdlib.ring"
see ringvm_fileslist()
Output:
B:/ring/tests/scripts/fileslist.ring
B:ringbinstdlib.ring
eval
stdlib.ring
stdlib.rh
stdclasses.ring
stdfunctions.ring
stdbase.ring
stdstring.ring
stdlist.ring
stdstack.ring
stdqueue.ring
stdmath.ring
stddatetime.ring
stdfile.ring
stdsystem.ring
stddebug.ring
stddatatype.ring
70.14. ringvm_fileslist() function 801](https://image.slidesharecdn.com/821pdfsamfayedringdoc1-180722102939/85/The-Ring-programming-language-version-1-7-book-Part-83-of-196-10-320.jpg)
More Related Content
What's hot (20)
Similar to The Ring programming language version 1.7 book - Part 83 of 196 (20)
More from Mahmoud Samir Fayed (20)
Recently uploaded (20)
The Ring programming language version 1.7 book - Part 83 of 196
- 1. CHAPTER SEVENTY LOW LEVEL FUNCTIONS In this chapter we will learn about the low level functions provided by Ring • callgc() • varptr() • space() • nullpointer() • object2pointer() • pointer2object() • ptrcmp() • ringvm_cfunctionslist() • ringvm_functionslist() • ringvm_classeslist() • ringvm_packageslist() • ringvm_memorylist() • ringvm_calllist() • ringvm_fileslist() • ringvm_settrace() • ringvm_tracedata() • ringvm_traceevent() • ringvm_tracefunc() • ringvm_scopescount() • ringvm_evalinscope() • ringvm_passerror() • ringvm_hideerrorMsg() • ringvm_callfunc() • ringvm_see() • ringvm_give() 792
- 2. Ring Documentation, Release 1.7 70.1 callgc() function Use this function to force calling the garbage collector during function execution when you use a loop that create temp. variables that you don’t free using the assignment operation. It’s very rare to need this function but it’s useful when you create something like event-loop for your game engine and start creating lists on the fly when you call functions. Example While True # process events # call functions using temp. lists like myfunc(["temp list"]) # call the garbage collector callgc() End Tip: In Ring the garbage collector works automatically in the end of function execution or when you use the assign- ment statement. 70.2 varptr() function Use the varptr() function when you need to pass a pointer to a C/C++ function. Syntax: varptr(cVariableName,cPointerType) —> Low Level Object (C Pointer) example: r = 10 z = 20 see r + nl see varptr("r","int") see varptr("z","int") Output: 10 00E3C740 int 2 00E3BEC0 int 2 Note: the low level object is a list contains three items (The Pointer, The Type, The Status) 70.3 space() function Use the space function to allocate a specific number of bytes in Memory. 70.1. callgc() function 793
- 3. Ring Documentation, Release 1.7 Syntax: Space(nBytesCount) ---> String Example: mystring = space(200) See "String Size : " + len(mystring) + nl See "String : " + mystring + nl See "String Pointer : " See varptr("mystring","char *") Output: String Size : 200 String : String Pointer : 00FF8FE8 char * 2 Note: You may need the space() and VarPtr() functions to pass buffers to C functions. 70.4 nullpointer() function You may need to pass the NULL pointer to a C function that may expect a pointer as parameter and accept NULL pointers for optional parameters. Example: The next example uses the SDL_BlitSurface() function from the LibSDL Library through RingSDL The function accept SDL_Rect pointers in the second and the last parameter. Also the function accept NULL pointers, so we can pass them using the NULLPointer() Function. SDL_BlitSurface(text, nullpointer(), surface, nullpointer()) Note: The previous code doesn’t work alone, you need to learn how to use RingSDL first. Tip: We can pass NULL as parameter instead of using NULLPointer() 70.5 object2pointer() function Use this function to get a C pointer for Ring lists and objects Syntax: object2pointer(List|Object) --> Low Level Object ( C Pointer ) 70.6 pointer2object() function Use this function to get the Ring list and/or object from the low level object (C Pointer) 70.4. nullpointer() function 794
- 4. Ring Documentation, Release 1.7 Syntax: pointer2object(Low Level Object) ---> List|Object Example: # Create the list mylist = 1:5 # Create pointer to the list x = object2pointer(mylist) see x see nl # Add items to the list mylist + "welcome" # print the list items y = pointer2object(x) see y Output: 0069A5D8 OBJECTPOINTER 0 1 2 3 4 5 welcome Note: In Ring the assignment operator copy lists and objects by value, to copy by reference Just use the ob- ject2pointer() and pointer2object() functions. Tip: The object2pointer() and pointer2object() are used in the stdlib - Tree Class implementation to create a reference for the parent node (object) in the child node (another object). 70.7 ptrcmp() function We can compare between two pointers (C Objects) using the ptrcmp() function. Syntax: ptrcmp(oObject1,oObject2) ---> value = 1 if oObject1 = oObject2 value = 0 if oObject1 != oObject2 Example: fp = fopen("ptrcmp.ring","r") fp2 = fp fp3 = fopen("ptrcmp.ring","r") 70.7. ptrcmp() function 795
- 5. Ring Documentation, Release 1.7 see ptrcmp(fp,fp2) + nl see ptrcmp(fp,fp3) + nl fclose(fp) fclose(fp3) Output: 1 0 70.8 ringvm_cfunctionslist() function The Function return a list of functions written in C. Syntax: RingVM_CFunctionsList() ---> List Example: See RingVM_CFunctionsList() 70.9 ringvm_functionslist() function The Function return a list of functions written in Ring. Each List Member is a list contains the next items • Function Name • Program Counter (PC) - Function Position in Byte Code. • Source Code File Name • Private Flag (For Private Methods in Classes) Syntax: RingVM_FunctionsList() ---> List Example: test() func test see ringvm_functionslist() Output: test 8 B:/ring/tests/scripts/functionslist.ring 0 70.8. ringvm_cfunctionslist() function 796
- 6. Ring Documentation, Release 1.7 70.10 ringvm_classeslist() function The Function return a list of Classes. Each List Member is a list contains the next items • Class Name • Program Counter (PC) - Class Position in Byte Code. • Parent Class Name • Methods List • Flag (Is parent class information collected) • Pointer to the package (or NULL if no package is used) Syntax: RingVM_ClassesList() ---> List Example: see ringvm_classeslist() class class1 func f1 class class2 from class1 class class3 from class1 Output: class1 9 f1 13 B:/ring/tests/scripts/classeslist.ring 0 0 00000000 class2 16 class1 0 00000000 class3 20 class1 0 00000000 70.11 ringvm_packageslist() function The Function return a list of Packages. Each List Member is a list contains the next items • Package Name 70.10. ringvm_classeslist() function 797
- 7. Ring Documentation, Release 1.7 • Classes List Syntax: RingVM_PackagesList() ---> List Example: see ringvm_packageslist() package package1 class class1 package package2 class class1 package package3 class class1 Output: package1 class1 11 0 00FEF838 package2 class1 17 0 00FEF978 package3 class1 23 0 00FEFF68 70.12 ringvm_memorylist() function The Function return a list of Memory Scopes and Variables. Each List Member is a list contains variables in a different scope. Each Item in the scope list is a list contains the next items • Variable Name • Variable Type • Variable Value • Pointer Type (List/Item) if the value is a list • Private Flag (if the variable is an attribute in a Class) Syntax: 70.12. ringvm_memorylist() function 798
- 8. Ring Documentation, Release 1.7 RingVM_MemoryList() ---> List Example: x = 10 test() func test y = 20 see ringvm_memorylist() Output: true 2 1 0 0 false 2 0 0 0 nl 1 0 0 null 1 0 0 ring_gettemp_var 4 00000000 0 0 ccatcherror 1 NULL 0 0 ring_settemp_var 4 00000000 0 0 ring_tempflag_var 2 0 0 0 stdin 3 50512DB8 file 0 0 70.12. ringvm_memorylist() function 799
- 9. Ring Documentation, Release 1.7 0 stdout 3 50512DD8 file 0 0 0 stderr 3 50512DF8 file 0 0 0 this 4 00000000 0 0 sysargv 3 B:ringbin/ring B:/ring/tests/scripts/memorylist.ring 0 0 x 2 10 0 0 y 2 20 0 0 70.13 ringvm_calllist() function The Function return a list of the functions call list. Each List Member is a list contains the next items • Function Type • Function Name • Program Counter (PC) • Stack Pointer (SP) • Temp. Memory List • Method or Function Flag • Caller PC • FuncExec Flag • ListStart Flag 70.13. ringvm_calllist() function 800
- 10. Ring Documentation, Release 1.7 • Nested Lists Pointer • State List Syntax: RingVM_CallList() ---> List Example: hello() func hello test() func test mylist = ringvm_calllist() for t in mylist see t[2] + nl next Output: function hello() in file B:/ring/tests/scripts/calllist.ring called from line 1 function test() in file B:/ring/tests/scripts/calllist.ring called from line 3 ringvm_calllist 70.14 ringvm_fileslist() function Function return a list of the Ring Files. Syntax: RingVM_FilesList() ---> List Example: load "stdlib.ring" see ringvm_fileslist() Output: B:/ring/tests/scripts/fileslist.ring B:ringbinstdlib.ring eval stdlib.ring stdlib.rh stdclasses.ring stdfunctions.ring stdbase.ring stdstring.ring stdlist.ring stdstack.ring stdqueue.ring stdmath.ring stddatetime.ring stdfile.ring stdsystem.ring stddebug.ring stddatatype.ring 70.14. ringvm_fileslist() function 801