This document provides an overview of command line options available in the Ring programming language. Some key options include: - -tokens, which prints a list of tokens in the source code file. - -rules, which prints grammar rules applied to the tokens. - -ic and -icfinal, which print the intermediate and final bytecode before and after execution. - -cgi, which prints HTTP response headers before error messages. - -norun, which compiles but does not run the program. - -ins, which prints instruction operation codes before execution. - -performance, which prints clock times before and after program execution. - -go, which generates an object file.

1. Ring Documentation, Release 1.8
Hello
How are you?
Welcome to Ring
one
two
three
67.6 Using $ and @ in the start of the variable name
You can use any unicode character in the variable name also we can use $ and @ in the name.
This feature may help, for example we can start global variables with $ and the object attributes with @.
In other languages like Ruby this is the rule, In the Ring language this is just an option without any force from the
Compiler.
example:
$global_variable = 5
new test { hello() }
class test
@instance_variable = 10
func hello
local_variable = 15
see "Global : " + $global_variable + nl +
"Instance : " + @instance_variable + nl +
"Local : " + local_variable + nl
Output:
Global : 5
Instance : 10
Local : 15
67.7 Using the ‘elseif’ keyword as ‘but’ in if statement
if you don’t like the ‘but’ keyword in if statement Then you can use the ‘elseif’ keyword.
Example:
give x
if x = 1 see "one"
elseif x=2 see "two"
elseif x=3 see "three"
elseif x=4 see "four"
else see "other"
ok
see nl
67.6. Using $ and @ in the start of the variable name 781

2. Ring Documentation, Release 1.8
67.8 Using the ‘else’ keyword as ‘other’ in switch statement
if you don’t like the ‘other’ keyword in switch statement Then you can use the ‘else’ keyword.
Also you can replace ‘else’ with ‘other’ in if statement.
i.e. ‘other’ keyword is the same as ‘else’ keyword.
Example:
x = 1
switch x
on 10
see "10" + nl
else
see "not 10" + nl
end
Output:
not 10
67.9 Using the ‘end’ keyword in different control structures
We can use the ‘end’ keyword to close different control structures
• If statement
• For loop
• Switch
• While
• Try-Catch
Example:
see "if statement.." + nl
x = 1
if x = 1
see "one" + nl
elseif x=2
see "two" + nl
elseif x=3
see "three" + nl
end
see "for loop.." + nl
for t = 1 to 10
see t
end
see nl
see "switch..." + nl
x = 1
switch x
on 1 see "one" + nl
on 2 see "two" + nl
end
67.8. Using the ‘else’ keyword as ‘other’ in switch statement 782

3. Ring Documentation, Release 1.8
see "try catch..." + nl
try
x = 1 / 0
catch
see "catching error" + nl
end
Output:
if statement..
one
for loop..
12345678910
switch...
one
try catch...
catching error
67.10 Using braces to start and end different control structures
We can use braces { } to start and end different control structures
• If statement
• For loop
• Switch
• While
• Try-Catch
Example:
see "if statement.." + nl
x = 1
if x = 1 {
see "one" + nl
elseif x=2
see "two" + nl
elseif x=3
see "three" + nl
}
see "for loop.." + nl
for t = 1 to 10 {
see t
}
see nl
see "switch..." + nl
x = 1
switch x {
on 1 see "one" + nl
on 2 see "two" + nl
}
see "try catch..." + nl
try {
67.10. Using braces to start and end different control structures 783

4. Ring Documentation, Release 1.8
x = 1 / 0
catch
see "catching error" + nl
}
Output:
if statement..
one
for loop..
12345678910
switch...
one
try catch...
catching error
67.11 Using ‘put’ and ‘get’ as ‘see’ and ‘give’
We can replace the ‘see’ keyword with the ‘put’ keyword.
Also we can replacew the ‘give’ keyword with the ‘get’ keyword.
Example:
put "Hello World" + nl
put "Enter Your Name ? " Get Name
Put "Hello " + Name
67.12 Using ‘case’ as ‘on’ in switch statements
We can replace the ‘on’ keyword with ‘case’ keyword in the switch statement.
Example (1) :
for x=1 to 10
switch x
case 1 put "one" + nl
case 2 put "two" + nl
case 3 put "thre" + nl
else put "else" + nl
end
end
Example (2) :
for x=1 to 10 {
switch x {
case 1 put "one" + nl
case 2 put "two" + nl
case 3 put "thre" + nl
else put "else" + nl
}
}
67.11. Using ‘put’ and ‘get’ as ‘see’ and ‘give’ 784

5. Ring Documentation, Release 1.8
67.13 Using ‘def’ as ‘func’ in functions/methods definition
We can use the ‘def’ keyword as the ‘func’ keyword to define functions and methods.
Example:
one() two()
def one put "one" + nl
def two put "two" + nl
67.14 Using braces { } in Packages/Classes/Functions
Example:
load "stdlib.ring"
import mypackage
new myclass {
myfunc()
}
package mypackage
{
class myclass
{
func myfunc
{
print("Hello, World!n")
}
}
}
67.15 Using ‘end’ keyword after Packages/Classes/Functions
Example:
import mypackage
new myclass {
myfunc()
}
package mypackage
class myclass
def myfunc
put "Hello, World!"
end
end
end
67.13. Using ‘def’ as ‘func’ in functions/methods definition 785

6. Ring Documentation, Release 1.8
67.16 Using ‘endpackage’/’endclass’/’endfunc’ keywords after Pack-
ages/Classes/Functions
Example:
import mypackage
new myclass { myfunc() }
package mypackage
class myclass
func myfunc
see "welcome" + nl
endfunc
endclass
endpackage
67.17 Ignore new lines after keywords
Starting from Ring 1.8 the compiler will ignore new lines after keywords that expect tokens after it
Example:
see
"
Hello, World!
"
test()
func
#======================#
Test
#======================#
?
"
Hello from the Test function
"
Output:
Hello, World!
Hello from the Test function
67.16. Using ‘endpackage’/’endclass’/’endfunc’ keywords after Packages/Classes/Functions 786

7. CHAPTER
SIXTYEIGHT
INTRODUCTION TO THE TYPE HINTS LIBRARY
In this chapter we will learn about the Type Hints Library
68.1 Why Type Hints?
Using this library we can add the type information to the source code which will be very useful for tools like
• Code Editors
• Static-Analysis
Note: Ring is a dynamic language, No type checking will be done by the compiler.
68.2 Example
The next example will use the Type Hints library
load "typehints.ring"
see sum(3,4) + nl ;
see sayHello("Mahmoud");
int func sum(int x,int y) {
return x+y ;
}
string func sayHello(string name) {
return "Hello " + name ;
}
68.3 User Types
The Type Hints library is very powerful and will support user types (Classes) automatically
Example:
load "typehints.ring"
import mypackage
787

8. Ring Documentation, Release 1.8
test() { main([:one,:two,:three]) }
myclass func test() {
see "Testing User Types!" + nl
return new myclass
}
package mypackage {
public class myclass {
public static void func main(list args) {
see "welcome" + nl
see args
}
}
}
68.4 Using Types inside Code
Also you can use the types inside the code (not only the function prototype)
Example:
load "typehints.ring"
int sum = sum(3,4)
string msg = sayHello("Mahmoud")
see "Sum = " + sum + nl + msg + nl
int func sum(int x,int y) {
return x+y ;
}
string func sayHello(string name) {
return "Hello " + name ;
}
68.5 Rules
• To use the types in the function prototype you must use ‘(‘ and ‘)’ around parameters
• To use the types in the function code, You must set the variable value (Assignment).
The next types are defined by the library
# Low Level Types
char
unsigned
signed
int
short
long
float
68.4. Using Types inside Code 788

9. Ring Documentation, Release 1.8
double
void
# High Level Types
string
list
number
object
# Other
public
static
abstract
protected
override
68.5. Rules 789

10. CHAPTER
SIXTYNINE
COMMAND LINE OPTIONS
The ring language takes source code file (.ring) or the object file (.ringo) as input to execute, also the language provide
other options like
Option Description
-tokens Print a list of tokens in the source code file
-rules Print grammar rules applied on the tokens
-ic Print the intermediate byte code (before execution)
-icfinal Print the final byte code (after execution)
-cgi Print http response header before error messages
-norun Don’t run the program after compiling
-ins Print instruction operation code before execution
-performance Print clock before and after program execution
-go Generate Object File
-w Display Warnings
69.1 Printing Tokens
Example:
Func Main
See "Hello World" + nl
for x = 1 to 10
see x + nl
next
test()
func test
see "welcome" + nl
o1 = new point { x=10 y=20 z=30 }
see o1
class point x y z
Command:
ring test.ring -tokens -norun
Output:
===================================================
Tokens - Generated by the Scanner
===================================================
790