The Ring programming language version 1.3 book - Part 18 of 88
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The document provides information about Ring programming language functions for working with ODBC databases. It describes functions for initializing an ODBC connection, listing available drivers and data sources, connecting to and disconnecting from a database, executing queries, fetching and retrieving result sets, and managing transactions. Functions covered include odbc_init(), odbc_drivers(), odbc_datasources(), odbc_close(), odbc_connect(), odbc_disconnect(), odbc_execute(), odbc_colcount(), odbc_fetch(), odbc_getdata(), odbc_tables(), odbc_columns(), odbc_autocommit(), odbc_commit(), and odbc_rollback().
![Ring Documentation, Release 1.3
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28.14 Get Active Source File Name
We can get the active source file name (*.ring) using the filename() function
Syntax:
filename() ---> String contains the active source file name.
Example:
see "Active Source File Name : " + filename() + nl
Output:
Active Source File Name : testsfilename.ring
Example:
if sysargv[2] = filename()
see "I'm the main program file!" + nl
# we can run tests here!
else
see "I'm a sub file in a program" + nl
ok
28.15 PrevFileName() Function
Using the PrevFileName() function we can get the previous active source file name.
The previous file would be the file of the caller function, Or the file of the function that we called before calling
PrevFileName().
Syntax:
prevfilename() ---> String contains the previous source file name.
Example:
The next function in stdlib.ring uses the PrevFileName() to know if the file of the caller function is the main source
file of the program or not.
Func IsMainSourceFile
if PrevFileName() = sysargv[2]
return true
ok
return false
28.14. Get Active Source File Name 148](https://image.slidesharecdn.com/171ringring-170612194227/85/The-Ring-programming-language-version-1-3-book-Part-18-of-88-1-320.jpg)
![Ring Documentation, Release 1.3
30.2 Main Menu
Example:
# Demo Program
while true
see "
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
" give nMenu see nl
# we can use Switch-ON-Other-OFF instead of IF-BUT-ELSE-OK
Switch nMenu
On 1 sayhello()
On 2 Sum()
On 3 Stars()
On 4
see "Enter Number : " give x
see "Output : "
Try
see Fact(number(x))
Catch
see "Error in parameters!" + nl
Done
On "5" return
Other see "bad option" + nl
Off
end
func sayhello
see "Enter your name ? " give fname
see "Hello " + fname + nl
func sum
see "number 1 : " give num1 see "number 2 : " give num2
see "Sum : " see 0 + num1 + num2
func stars
for x = 1 to 10
see space(8)
for y = 1 to x see "*" next see nl
next
func fact x if x = 1 return 1 else return x * fact(x-1) ok
30.2. Main Menu 154](https://image.slidesharecdn.com/171ringring-170612194227/85/The-Ring-programming-language-version-1-3-book-Part-18-of-88-7-320.jpg)
![Ring Documentation, Release 1.3
func space x y = "" for t=1 to x y += " " next return y
Output:
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
1
Enter your name ? Mahmoud Fayed
Hello Mahmoud Fayed
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
2
number 1 : 3
number 2 : 4
Sum : 7
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
3
*
**
***
****
*****
******
*******
********
*********
**********
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
30.2. Main Menu 155](https://image.slidesharecdn.com/171ringring-170612194227/85/The-Ring-programming-language-version-1-3-book-Part-18-of-88-8-320.jpg)
![Ring Documentation, Release 1.3
[3] Stars
[4] Fact
[5] Exit
4
Enter Number : 5
Output : 120
Main Menu
===========
[1] Say Hello
[2] Sum two numbers
[3] Stars
[4] Fact
[5] Exit
5
30.2. Main Menu 156](https://image.slidesharecdn.com/171ringring-170612194227/85/The-Ring-programming-language-version-1-3-book-Part-18-of-88-9-320.jpg)
The Ring programming language version 1.3 book - Part 18 of 88
- 1. Ring Documentation, Release 1.3 1 2 3 4 5 6 7 8 9 10 28.14 Get Active Source File Name We can get the active source file name (*.ring) using the filename() function Syntax: filename() ---> String contains the active source file name. Example: see "Active Source File Name : " + filename() + nl Output: Active Source File Name : testsfilename.ring Example: if sysargv[2] = filename() see "I'm the main program file!" + nl # we can run tests here! else see "I'm a sub file in a program" + nl ok 28.15 PrevFileName() Function Using the PrevFileName() function we can get the previous active source file name. The previous file would be the file of the caller function, Or the file of the function that we called before calling PrevFileName(). Syntax: prevfilename() ---> String contains the previous source file name. Example: The next function in stdlib.ring uses the PrevFileName() to know if the file of the caller function is the main source file of the program or not. Func IsMainSourceFile if PrevFileName() = sysargv[2] return true ok return false 28.14. Get Active Source File Name 148
- 2. Ring Documentation, Release 1.3 28.16 CurrentDir() Function Return the path of the current directory Syntax: CurrenDir() ---> String contains the path of the currect directory 28.17 ExeFileName() Function Return the Ring executable file name Syntax: exefilename() ---> String contains the Ring executable file name 28.18 ChDir() Function Change the current directory Syntax: ChDir(cNewPath) 28.19 ExeFolder() Function Return the Ring executable file path Syntax: exefolder() ---> String contains the Ring executable path 28.20 Version() Function Return the Ring version Syntax: version() ---> String contains the Ring version Output: 1.3 28.16. CurrentDir() Function 149
- 3. CHAPTER TWENTYNINE EVAL() AND DEBUGGING In this chapter we are going to learn about • Error Handling using Try/Catch/Done • Eval() function • Raise() function • Assert() function 29.1 Try/Catch/Done Syntax: Try Statements... Catch Statements... Done The statements in the Try block will be executed, if any error happens then the statements in the catch block will be executed. Inside the catch block we can use the variable cCatchError to get the error message Example: Try see 5/0 Catch see "Catch!" + nl + cCatchError Done Output: Catch! Error (R1) : Cann't divide by zero ! 29.2 Eval() Function We can execute code during the runtime from string using the Eval() function Syntax: 150
- 4. Ring Documentation, Release 1.3 Eval(cCode) Example: Eval("nOutput = 5+2*5 " ) See "5+2*5 = " + nOutput + nl Eval("for x = 1 to 10 see x + nl next") Eval("func test see 'message from test!' ") test() Output: 5+2*5 = 15 1 2 3 4 5 6 7 8 9 10 message from test! 29.3 Raise() Function We can raise an exception using the Raise() function Syntax: Raise(cErrorMessage) The function will display the error message then end the execution of the program. We can use Try/Catch/Done to avoid exceptions generated by raise() function. Example: nMode = 10 if nMode < 0 or nMode > 5 raise("Error : nMode not in the range 1:4") ok Output: Line 4 Error : nMode not in the range 1:4 In raise in file testsraise.ring Example: try testmode(6) catch see "avoid raise!" done testmode(-1) 29.3. Raise() Function 151
- 5. Ring Documentation, Release 1.3 func testmode nMode if nMode < 0 or nMode > 5 raise("Error : nMode not in the range 1:4") ok Output: avoid raise! Line 12 Error : nMode not in the range 1:4 In raise In function testmode() in file testsraise2.ring called from line 7 in file testsraise2.ring 29.4 Assert() Function We can use the Assert() function to test conditions before executing the code If the test fail the program will be terminated with an error message contains the assert condition. Syntax: Assert( condition ) Example: x = 10 assert( x = 10) assert( x = 100 ) Output: Line 3 Assertion Failed! In assert in file testsassert.ring 29.4. Assert() Function 152
- 6. CHAPTER THIRTY DEMO PROGRAMS In this chapter we will see simple demo programs • Language Shell • Main Menu 30.1 Language Shell We can create simple interactive programming environment using the next program while true see nl + "code:> " give cCode try eval(cCode) catch see cCatchError done end Output: code:> see "hello world" hello world code:> for x = 1 to 10 see x + nl next 1 2 3 4 5 6 7 8 9 10 code:> func test see "Hello from test" + nl code:> test() Hello from test code:> bye 153
- 7. Ring Documentation, Release 1.3 30.2 Main Menu Example: # Demo Program while true see " Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit " give nMenu see nl # we can use Switch-ON-Other-OFF instead of IF-BUT-ELSE-OK Switch nMenu On 1 sayhello() On 2 Sum() On 3 Stars() On 4 see "Enter Number : " give x see "Output : " Try see Fact(number(x)) Catch see "Error in parameters!" + nl Done On "5" return Other see "bad option" + nl Off end func sayhello see "Enter your name ? " give fname see "Hello " + fname + nl func sum see "number 1 : " give num1 see "number 2 : " give num2 see "Sum : " see 0 + num1 + num2 func stars for x = 1 to 10 see space(8) for y = 1 to x see "*" next see nl next func fact x if x = 1 return 1 else return x * fact(x-1) ok 30.2. Main Menu 154
- 8. Ring Documentation, Release 1.3 func space x y = "" for t=1 to x y += " " next return y Output: Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 1 Enter your name ? Mahmoud Fayed Hello Mahmoud Fayed Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 2 number 1 : 3 number 2 : 4 Sum : 7 Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 3 * ** *** **** ***** ****** ******* ******** ********* ********** Main Menu =========== [1] Say Hello [2] Sum two numbers 30.2. Main Menu 155
- 9. Ring Documentation, Release 1.3 [3] Stars [4] Fact [5] Exit 4 Enter Number : 5 Output : 120 Main Menu =========== [1] Say Hello [2] Sum two numbers [3] Stars [4] Fact [5] Exit 5 30.2. Main Menu 156
- 10. CHAPTER THIRTYONE ODBC FUNCTIONS This chapter contains the ODBC functions provided by the Ring programming language. • odbc_init() • odbc_drivers() • odbc_datasources() • odbc_close() • odbc_connect() • odbc_disconnect() • odbc_execute() • odbc_colcount() • odbc_fetch() • odbc_getdata() • odbc_tables() • odbc_columns() • odbc_autocommit() • odbc_commit() • odbc_rollback() 31.1 odbc_init() Function We can create ODBC Handle using the odbc_init() function Syntax: odbc_init() ---> ODBC Handle 31.2 odbc_drivers() Function We can get a list of ODBC drivers using the odbc_drivers() function Syntax: 157