The document provides a summary of errors that can occur in the Ring programming language. It lists 26 compilation errors, 35 runtime errors, 4 environment errors, and outlines the language grammar and virtual machine instructions. The errors are grouped into categories like syntax errors, runtime errors, and environment errors. Each error is given a short code and description.

1. Ring Documentation, Release 1.5.4
• Error (C7) : Error in list items
• Error (C8) : Parentheses ‘)’ is missing
• Error (C9) : Brackets ‘]’ is missing
• Error (C10) : Error in parent class name
• Error (C11) : Error in expression operator
• Error (C12) : No class definition
• Error (C13) : Error in variable name
• Error (C14) : Try/Catch miss the Catch keyword!
• Error (C15) : Try/Catch miss the Done keyword!
• Error (C16) : Error in Switch statement expression!
• Error (C17) : Switch statement without OFF
• Error (C18) : Missing closing brace for the block opened!
• Error (C19) : Numeric Overflow!
• Error (C20) : Error in package name
• Error (C21) : Unclosed control strucutre, ‘again’ is missing
• Error (C22) : Function redefinition, function is already defined!
• Error (C23) : Using ‘(‘ after number!
• Error (C24) : The parent class name is identical to the subclass name
• Error (C25) : Trying to access the self reference after the object name”
• Error (C26) : Class redefinition, class is already defined!
97.4 Runtime Errors
• Error (R1) : Cann’t divide by zero !
• Error (R2) : Array Access (Index out of range) !
• Error (R3) : Calling Function without definition !
• Error (R4) : Stack Overflow !
• Error (R5) : Can’t access the list item, Object is not list !
• Error (R6) : Variable is required
• Error (R7) : Can’t assign to a string letter more than one character
• Error (R8) : Variable is not a string
• Error (R9) : Using exit command outside loops
• Error (R10) : Using exit command with number outside the range
• Error (R11) : error in class name, class not found!
• Error (R12) : error in property name, property not found!
• Error (R13) : Object is required
97.4. Runtime Errors 1775

2. Ring Documentation, Release 1.5.4
• Error (R14) : Calling Method without definition !
• Error (R15) : error in parent class name, class not found!
• Error (R16) : Using braces to access unknown object !
• Error (R17) : error, using ‘Super’ without parent class!
• Error (R18) : Numeric Overflow!
• Error (R19) : Calling function with less number of parameters!
• Error (R20) : Calling function with extra number of parameters!
• Error (R21) : Using operator with values of incorrect type
• Error (R22) : Using loop command outside loops
• Error (R23) : Using loop command with number outside the range
• Error (R24) : Using uninitialized variable
• Error (R25) : Error in package name, Package not found!
• Error (R26) : Calling private method from outside the class
• Error (R27) : Using private attribute from outside the class
• Error (R28) : Using bad data type as step value
• Error (R29) : Using bad data type in for loop
• Error (R30) : parent class name is identical to child class name
• Error (R31) : Trying to destory the object using the self reference
• Error (R32) : The CALL command expect a variable contains string!
• Error (R33) : Bad decimals number (correct range >= 0 and <=14) !
• Error (R34) : Variable is required for the assignment operation
• Error (R35) : Can’t create/open the file!
• Error (R36) : The column number is not correct! It’s greater than the number of columns in the list
• Error (R37) : Sorry, The command is not supported in this context
• Error (R38) : Runtime Error in loading the dynamic library!
97.5 Environment Errors
• Error (E1) : Caught SegFault
• Error (E2) : Out of Memory
• Error (E3) : Deleting scope while no scope!
• Error (E4) : Long VM Instruction!
97.5. Environment Errors 1776

3. Ring Documentation, Release 1.5.4
97.6 Language Grammar
Program —> {statement}
Statement —> ‘package’ <Identifier> { ‘.’ <Identifier> } [’{‘ {statement} ‘}’] [’end’|’endpackage’]
Statement —> ‘class’ <Identifier> [ ‘from’|’:’|’<’ <Identifier> ] [’{‘ {statement} ‘}’][’end’|’endclass’]
Statement —> ‘func’|’def’ <Identifier> [ParaList] [’{‘ {statement} ‘}’][’end’|’endfunc’]
Statement —> ‘import’ <Identifier> { ‘.’ <Identifier> }
Statement —> ‘private’
Statement —> ‘load’ <Literal>
Statement —> ‘loadsyntax’ <Literal>
Statement —> ‘changeringkeyword’ <OldKeyword> <NewKeyword>
Statement —> ‘changeringoperator’ <OldOperator> <NewOperator>
Statement —> ‘see’|’put’ <Expr>
Statement —> ‘give’|’get’ <Identifier>
Statement —> ‘if’ <Expr> [’{‘] {statement} [ {‘but’|’elseif’ <Expr> {Statement} } ] [’else’ {Statement} ]
‘ok’|’end’|’}’
Statement —> ‘Switch’ <Expr> [’{‘] { ‘on’|’case’ <Expr> {statement} } [’other’ {Statement} ] ‘off’|’end’|’}’
Statement —> ‘for’ <Identifier> ‘=’ <Expr> ‘to’ <Expr> [ ‘step’ <Expr> ] [’{‘] {Statement} ‘next’|’end’|’}’
Statement —> ‘for’ <Identifier> ‘in’ <Expr> [ ‘step’ <Expr> ] [’{‘] {statement} ‘next’|’end’|’}’
Statement —> ‘while’ <Expr> [’{‘] {statement} ‘end’|’}’
Statement —> ‘do’ {statement} ‘again’ <Expr>
Statement —> ‘try’ {statement} [’{‘] ‘catch’ {statement} ‘done’|’end’|’}’
Statement —> ‘return’ <Expr>
Statement —> ‘bye’
Statement —> ‘exit’
Statement —> ‘loop’
Statement —> <Expr>
Statement —> epslion
ParaList —> epslion
ParaList —> [’(‘] <Identifier> [{ ‘,’ <Identifier> }] [’)’]
Expr —> <LogicNot> [{ ‘and’|’or’ <LogicNot> }]
LogicNot –> [’not’] <EqualOrNot>
EqualOrNot –> [ ‘=’|’!=’ ] <Compare>
Compare —> <BitOrXor> [ { ‘<’ | ‘>’ | ‘<=’ | ‘>=’ <BitOrXor> } ]
BitOrXor —> <BitAnd> [ { ‘|’ | ‘^’ <BitAnd> } ]
BitAnd —> <BitShift> [ { ‘&’ <BitShift> } ]
BitShift —> <Arithmetic> [ { ‘<<’ | ‘>>’ <Arithmetic> } ]
97.6. Language Grammar 1777

4. Ring Documentation, Release 1.5.4
Arithmetic —> <Term> [ { ‘+’ | ‘-‘ <Term> } ]
Term —> <Range> [ { ‘*’ | ‘/’ | ‘%’ <Range> } ]
Range —> <Factor> [ ‘:’ <Factor> ]
Factor —> <Identifier> [ {Mixer} ] [ ‘=’ <Expr> ]
Factor —> <Number>
Factor —> <Literal>
Factor —> ‘:’ <Identifier>
Factor —> ‘-‘ <Expr>
Factor —> ‘(‘ <Expr> ‘)’
Factor —> <List>
Factor —> ‘new’ <Identifier>
Factor —> <AnonymousFunction>
Factor —> ‘call’ <identifier> { ‘.’ <Identifier> } ‘(‘ <Parameters> ‘)’
List —> ‘[’ [ <Expr> { ‘,’ <Expr> } ] ‘]’
Mixer —> { ‘.’ <Identifier> }
Mixer —> ‘[’ <Expr> ‘]’
Mixer —> ‘(‘ [ <Expr> [ { ‘,’ <Expr> }] ] ‘)’
Mixer —> ‘{‘ {Statement} ‘}’
AnonymousFunction —> ‘func’|’def’| [<ParaList>] ‘{‘ {Statement} ‘}’
97.7 Virtual Machine (VM) Instructions
Definitions :-
• VM : Virtual Machine
• Stack : VM Stack
• IR : Instruction Register
• PC : Program Counter
• VP : Variable Pointer
• Stack[nSize] : Last Item in the Stack (Last In - First Out)
• VV : Variable Value (We have a Pointer to a variable, And we access this variable value)
(Stack and Variables)
97.7. Virtual Machine (VM) Instructions 1778

5. Ring Documentation, Release 1.5.4
Operation Description
• ICO_PUSHC
Add string from the IR to the stack
• ICO_PUSHN
Add number from the IR to the stack
• ICO_PUSHV
Replace VP in the stack[nSize] with the variable value
• ICO_LOADADDRESS
Read variable name from the IR, push VP to the stack
• ICO_ASSIGNMENT
Stack[nSize-1] VV = Stack[nSize] VV , POP
Stack[nSize]
• ICO_INC
Increment Number in Stack[nSize] by 1
• ICO_LOADAPUSHV
The same as ICO_LOADADDRESS then ICO_PUSHV
• ICO_NEWLINE
Store new line number (debug info)
• ICO_FREESTACK
Remove all items from the stack , nSize = 0
• ICO_FILENAME
Store the source code file name (debug info)
• ICO_FREELOADASCOPE
Free the Scope List of the current Expression
(Jump)
Operation Description
• ICO_JUMP
Set PC to new value from the IR
• ICO_JUMPZERO
If Stack[nSize] is a number = 0 then Set PC to new value
from the IR
• ICO_JUMPFOR
End of for loop
• ICO_JUMPONE
If Stack[nSize] is a number = 1 then Set PC to new value
from the IR
• ICO_JUMPZERO2
As ICO_JUMPZERO but add 1 to the stack (required
for many ‘AND’ conditions)
• ICO_JUMPONE2
As ICO_JUMPONE but add 1 to the stack (required for
many ‘OR’ conditions)
(Compare)
97.7. Virtual Machine (VM) Instructions 1779

6. Ring Documentation, Release 1.5.4
Operation Description
• ICO_LESSEQUAL
If stack[nSize-1] <= stack[nSize] , POP stack[nSize], set
Stack[nSize-1] = 1 else set Stack[nSize-1] = 0
• ICO_EQUAL
If stack[nSize-1] = stack[nSize] , POP stack[nSize], set
Stack[nSize-1] = 1 else set Stack[nSize-1] = 0
• ICO_LESS
If stack[nSize-1] < stack[nSize] , POP stack[nSize], set
Stack[nSize-1] = 1 else set Stack[nSize-1] = 0
• ICO_GREATER
If stack[nSize-1] > stack[nSize] , POP stack[nSize], set
Stack[nSize-1] = 1 else set Stack[nSize-1] = 0
• ICO_GREATEREQUAL
If stack[nSize-1] >= stack[nSize] , POP stack[nSize], set
Stack[nSize-1] = 1 else set Stack[nSize-1] = 0
• ICO_NOTEQUAL
If stack[nSize-1] != stack[nSize] , POP stack[nSize], set
Stack[nSize-1] = 1 else set Stack[nSize-1] = 0
(Math)
Operation Description
• ICO_SUM
Stack[nSize-1] = Stack[nSize-1] + Stack[nSize] , POP
stack[nSize]
• ICO_SUB
Stack[nSize-1] = Stack[nSize-1] - Stack[nSize] , POP
stack[nSize]
• ICO_MUL
Stack[nSize-1] = Stack[nSize-1] * Stack[nSize] , POP
stack[nSize]
• ICO_DIV
Stack[nSize-1] = Stack[nSize-1] / Stack[nSize] , POP
stack[nSize]
• ICO_MOD
Stack[nSize-1] = Stack[nSize-1] % Stack[nSize] , POP
stack[nSize]
• ICO_NEG
Stack[nSize] = - Stack[nSize-1]
• ICO_PLUSPLUS
Stack[nSize] = Stack[nSize] + 1
• ICO_MINUSMINUS
Stack[nSize] = Stack[nSize] - 1
(Logic)
Operation Description
• ICO_AND
Stack[nSize-1] = Stack[nSize-1] && Stack[nSize] ,
POP stack[nSize]
• ICO_OR
Stack[nSize-1] = Stack[nSize-1] || Stack[nSize] , POP
stack[nSize]
• ICO_NOT
Stack[nSize] = ! Stack[nSize]
(Lists)
97.7. Virtual Machine (VM) Instructions 1780

7. Ring Documentation, Release 1.5.4
Operation Description
• ICO_LISTSTART
Start New List in Temp. Memory
• ICO_LISTITEM
Add List Item
• ICO_LISTEND
End List
• ICO_LOADINDEXADDRESS
Stack[nSize-1] = Stack[nSize-1] VV [ Stack[nSize] ] ,
POP stack[nSize]
(Functions)
Operation Description
• ICO_LOADFUNC
Find function
• ICO_CALL
Call function
• ICO_RETURN
Return from function
• ICO_RETNULL
Return NULl from function
• ICO_RETFROMEVAL
Return after eval()
• ICO_RETITEMREF
Return the list item reference - not the value
• ICO_NEWFUNC
Start new function
• ICO_BLOCKFLAG
Flag to determine where to jump later (after
ICO_RETURN)
• ICO_FUNCEXE
Start executing function
• ICO_ENDFUNCEXE
End function execution
• ICO_ANONYMOUS
Anonymous function
(User Interface)
Operation Description
• ICO_PRINT
Print value to the standard output
• ICO_GIVE
Get input from the keyboard
(End Program/Loop)
97.7. Virtual Machine (VM) Instructions 1781

8. Ring Documentation, Release 1.5.4
Operation Description
• ICO_BYE
End execution of VM
• ICO_EXITMARK
Place to exit to from a loop
• ICO_POPEXITMARK
Remove exit mark
• ICO_EXIT
Break from one loop or more
• ICO_LOOP
Continue to next loop
(For Better Performance)
Operation Description
• ICO_PUSHP
Push pointer to the stack
• ICO_INCP
Increment variable value using pointer
• ICO_PUSHPV
Push value of variable using variable pointer
• ICO_INCJUMP
Increment then jump
• ICO_INCPJUMP
Increment using pointer then jump
• ICO_JUMPVARLENUM
Jump if variable value is <= numeric value
• ICO_JUMPVARPLENUM
Jump if variable value (using pointer) <= numeric value
• ICO_LOADFUNCP
Push function pointer
• ICO_PUSHPLOCAL
Push pointer to local variable
• ICO_INCLPJUMP
Increment value using pointer to local variable then
jump
• ICO_JUMPVARLPLENUM
Jump if the variable value (using pointer) <= numeric
value
• ICO_INCPJUMPSTEP1
Increment value using variable pointer then jump (for
loop step = 1)
• ICO_JUMPVARPLENUMSTEP1
Increment value using variable pointer then jump (for
loop step = 1)
(Try-Catch-Done)
97.7. Virtual Machine (VM) Instructions 1782

9. Ring Documentation, Release 1.5.4
Operation Description
• ICO_TRY
Start try region
• ICO_DONE
End try region
(Duplicate and Range)
Operation Description
• ICO_DUPLICATE
Duplicate stack value
• ICO_RANGE
Create list from value to value
(OOP)
Operation Description
• ICO_NEWOBJ
Create new object, get class name from the IR, push ob-
ject pointer to the stack.
• ICO_SETSCOPE
Called after creating new object, set the active scope to
be the object scope.
• ICO_LOADSUBADDRESS
Get object attribute, push the pointer to the stack.
• ICO_LOADMETHOD
Find object method
• ICO_AFTERCALLMETHOD
Used after calling a method - normal case
• ICO_AFTERCALLMETHOD2
Used after calling a method - second case
• ICO_NEWCLASS
Start new class region
• ICO_BRACESTART
Open brace
• ICO_BRACEEND
End brace
• ICO_IMPORT
Import package
• ICO_PRIVATE
start private attributes region
• ICO_SETPROPERTY
set attribute value - check for setter.
• ICO_CALLCLASSINIT
call call init() method.
(Other)
97.7. Virtual Machine (VM) Instructions 1783

10. Ring Documentation, Release 1.5.4
Operation Description
• ICO_SETREFERENCE
Copy by reference
• ICO_KILLREFERENCE
Remove reference
• ICO_ASSIGNMENTPOINTER
Determine the left side variable
• ICO_BEFOREEQUAL
Determine operators like += , -= , ... etc
(Bitwise Operators)
Operation Description
• ICO_BITAND
Stack[nSize-1] = Stack[nSize-1] & Stack[nSize] , POP
stack[nSize]
• ICO_BITOR
Stack[nSize-1] = Stack[nSize-1] | Stack[nSize] , POP
stack[nSize]
• ICO_BITXOR
Stack[nSize-1] = Stack[nSize-1] ^ Stack[nSize] , POP
stack[nSize]
• ICO_BITNOT
Stack[nSize] = ! Stack[nSize]
• ICO_BITSHL
Stack[nSize-1] = Stack[nSize-1] << Stack[nSize] , POP
stack[nSize]
• ICO_BITSHR
Stack[nSize-1] = Stack[nSize-1] >> Stack[nSize] , POP
stack[nSize]
(For Step)
Operation Description
• ICO_STEPNUMBER
Determine step number in for loop
• ICO_POPSTEP
POP step number from steps stack
• ICO_LOADAFIRST
Load the first address of variable name
97.7. Virtual Machine (VM) Instructions 1784